WorldWideScience

Sample records for ozone precursor monitoring

  1. Distribution and urban-suburban differences in ground-level ozone and its precursors over Shenyang, China

    Science.gov (United States)

    Liu, Ningwei; Ren, Wanhui; Li, Xiaolan; Ma, Xiaogang; Zhang, Yunhai; Li, Bingkun

    2018-03-01

    Hourly mixing ratio data of ground-level ozone and its main precursors at ambient air quality monitoring sites in Shenyang during 2013-2015 were used to survey spatiotemporal variations in ozone. Then, the transport of ozone and its precursors among urban, suburban, and rural sites was examined. The correlations between ozone and some key meteorological factors were also investigated. Ozone and O x mixing ratios in Shenyang were higher during warm seasons and lower during cold ones, while ozone precursors followed the opposite cycle. Ozone mixing ratios reached maximum and minimum values in the afternoon and morning, respectively, reflecting the significant influence of photochemical production during daytime and depletion via titration during nighttime. Compared to those in downtown Shenyang, ozone mixing ratios were higher and the occurrence of peak values were later in suburban and rural areas downwind of the prevailing wind. The differences were most significant in summer, when the ozone mixing ratios at one suburban downwind site reached a maximum value of 35.6 ppb higher than those at the downtown site. This suggests that photochemical production processes were significant during the transport of ozone precursors, particularly in warm seasons with sufficient sunlight. Temperature, total radiation, and wind speed all displayed positive correlations with ozone concentration, reflecting their important role in accelerating ozone formation. Generally, the correlations between ozone and meteorological factors were slightly stronger at suburban sites than in urban areas, indicating that ozone levels in suburban areas were more sensitive to these meteorological factors.

  2. Seasonal Changes in Tropospheric Ozone Concentrations over South Korea and Its Link to Ozone Precursors

    Science.gov (United States)

    Jung, H. C.; Moon, B. K.; Wie, J.

    2017-12-01

    Concentration of tropospheric ozone over South Korea has steadily been on the rise in the last decades, mainly due to rapid industrializing and urbanizing in the Eastern Asia. To identify the characteristics of tropospheric ozone in South Korea, we fitted a sine function to the surface ozone concentration data from 2005 to 2014. Based on fitted sine curves, we analyzed the shifts in the dates on which ozone concentration reached its peak in the calendar year. Ozone monitoring sites can be classified into type types: where the highest annual ozone concentration kept occurring sooner (Esites) and those that kept occurring later (Lsites). The seasonal analysis shows that the surface ozone had increased more rapidly in Esites than in Lsites in the past decade during springtime and vice-versa during summertime. We tried to find the reason for the different seasonal trends with the relationship between ozone and ozone precursors. As a result, it was found that the changes in the ground-level ozone concentration in the spring and summer times are considerably influenced by changes in nitrogen dioxide concentration, and this is closely linked to the destruction (production) process of ozone by nitrogen dioxide in spring (summer). The link between tropospheric ozone and nitrogen dioxide discussed in this study will have to be thoroughly examined through climate-chemistry modeling in the future. Acknowledgements This research was supported by the Korea Ministry of Environment (MOE) as "Climate Change Correspondence Program."

  3. Increase of ozone concentrations, its temperature sensitivity and the precursor factor in South China

    Directory of Open Access Journals (Sweden)

    Y. C. Lee

    2014-08-01

    Full Text Available Concerns have been raised about the possible connections between the local and regional photochemical problem and global warming. The current study assesses the trend of ozone in Hong Kong and the Pearl River Delta (PRD in South China and investigates the interannual changes of sensitivity of ozone to air temperature, as well as the trends in regional precursors. Results reveal, at the three monitoring sites from the mid-1990s to 2010, an increase in the mean ozone concentrations from 1.0 to 1.6 µg m−3 per year. The increase occurred in all seasons, with the highest rate in autumn. This is consistent with trends and temperature anomalies in the region. The increase in the sensitivity of ozone to temperature is clearly evident from the correlation between ozone (OMI [Ozone Monitoring Instrument] column amount and surface air temperature (from the Atmospheric Infrared Sounder displayed in the correlation maps for the PRD during the prominently high ozone period of July–September. It is observed to have increased from 2005 to 2010, the latter being the hottest year on record globally. To verify this temporal change in sensitivity, the ground-level trends of correlation coefficients/regression slopes are analysed. As expected, results reveal a statistically significant upward trend over a 14-year period (1997–2010. While the correlation revealed in the correlation maps is in agreement with the corresponding OMI ozone maps when juxtaposed, temperature sensitivity of surface ozone also shows an association with ozone concentration, with R=0.5. These characteristics of ozone sensitivity are believed to have adverse implications for the region. As shown by ground measurements and/or satellite analyses, the decrease in nitrogen oxides (NO2 and NOx in Hong Kong is not statistically significant while NO2 of the PRD has only very slightly changed. However, carbon dioxide has remarkably declined in the whole region. While these observations concerning

  4. Study to determine the nature and extent of ozone and ozone precursor transport in selected areas of California. Final report

    International Nuclear Information System (INIS)

    Roberts, P.T.; Musarra, S.; Smith, T.B.; Lurmann, F.W.

    1992-04-01

    The project was designed to assess the contribution of transported pollutants to violations of the state ozone standard within the air basins covered by the report using existing data and advanced data analysis techniques. The objectives of the project were to determine the characteristics of ozone and ozone precursor transport within the California air basins covered by the report and to identify whether the contribution of transported pollutants to ozone violations in each downwind area was inconsequential, significant, or overwhelming, relative to locally-emitted pollutants. The precursor pollutants of interest were nitrogen oxides and reactive organic gases. The project evaluated transport to the following areas: The Broader Sacramento Area and the Upper Sacramento Valley; The North Central Coast Air Basin; The Southeast Desert Air Basin (SEDAB); and the Imperial County portion of the SEDAB

  5. Assessing the effects of oil sands related ozone precursor emissions on ambient ozone levels in the Alberta oil sands region, Canada

    Science.gov (United States)

    Cho, Sunny; Vijayaraghavan, Krish; Spink, David; Cosic, Biljana; Davies, Mervyn; Jung, Jaegun

    2017-11-01

    A study was undertaken to determine whether, and the extent to which, increased ground-level ozone (O3) precursor emissions from oil sands development have impacted ambient air quality in the north-eastern Alberta, Canada, over the period 1998 to 2012. Temporal trends in emissions of O3 precursors (NOx and VOC) and ambient air concentrations of O3 precursors, and O3 were examined using the Theil-Sen statistical analysis method. Statistically significant correlations between NOx emissions and ambient NOx concentrations were found mainly near surface (open-pit) mining areas where mine fleets are a large source of NOx emissions. No statistically significant trends in the 4th highest daily maximum 8-hr average O3 at any of the continuous and passive ambient air monitoring stations were found. A significant long-term decrease in monthly averaged O3 is observed at some ambient monitoring sites in summer. A visual examination of long-term variations in annual NOx and VOC emissions and annual 4th highest daily maximum 8-hr O3 concentrations does not reveal any indication of a correlation between O3 concentrations and O3 precursor emissions or ambient levels in the study area. Despite a significant increase in oil sands NOx emissions (8%/yr), there is no statistically significant increase in long-term O3 concentrations at any of monitoring stations considered. This suggests that there is surplus NOx available in the environment which results in a titration of ambient O3 in the areas that have ambient monitoring. The limited ambient O3 monitoring data distant from NOx emission sources makes it impossible to assess the impact of these increased O3 precursor levels on O3 levels on a regional scale. As a precautionary measure, the increasing oil sands development O3 precursor emissions would require that priority be given to the management of these emissions to prevent possible future O3 ambient air quality issues.

  6. Impacts of Lowered Urban Air Temperatures on Precursor Emission and Ozone Air Quality.

    Science.gov (United States)

    Taha, Haider; Konopacki, Steven; Akbari, Hashem

    1998-09-01

    Meteorological, photochemical, building-energy, and power plant simulations were performed to assess the possible precursor emission and ozone air quality impacts of decreased air temperatures that could result from implementing the "cool communities" concept in California's South Coast Air Basin (SoCAB). Two pathways are considered. In the direct pathway, a reduction in cooling energy use translates into reduced demand for generation capacity and, thus, reduced precursor emissions from electric utility power plants. In the indirect pathway, reduced air temperatures can slow the atmospheric production of ozone as well as precursor emission from anthropogenic and biogenic sources. The simulations suggest small impacts on emissions following implementation of cool communities in the SoCAB. In summer, for example, there can be reductions of up to 3% in NO x emissions from in-basin power plants. The photochemical simulations suggest that the air quality impacts of these direct emission reductions are small. However, the indirect atmospheric effects of cool communities can be significant. For example, ozone peak concentrations can decrease by up to 11% in summer and population-weighted exceedance exposure to ozone above the California and National Ambient Air Quality Standards can decrease by up to 11 and 17%, respectively. The modeling suggests that if these strategies are combined with others, such as mobile-source emission control, the improvements in ozone air quality can be substantial.

  7. The influence of different matrices on the nature and content of haloacetic acids precursors in ozonized water

    Directory of Open Access Journals (Sweden)

    Molnar Jelena J.

    2012-01-01

    Full Text Available This paper investigates the influence of different matrices (groundwater a realistic natural matrix and commercial humic acid solution a synthetic matrix on the nature and content of haloacetic acid (HAA precursors in ozonized water (0.4 to 3.0 mg O3/mg DOC; pH 6. Natural organic matter (NOM characterization of the natural matrix showed it was largely of hydrophobic character (65% fulvic and 14% humic acids, with the hydrophilic fractions HPIA and HPI-NA at 12% and 9%, respectively. At approximately the same dissolved organic carbon (DOC content of the investigated matrices (~10 mg /L, a greater degree of hydrophobicity was seen in the humic acid solution than in the natural matrix, resulting in a higher content of HAA precursors (559 ± 21 μg/L in the synthetic matrix compared to 309 ± 15 μg/L in the natural matrix. By applying different ozone doses (0.4 to 3.0 mg O3/mg DOC, the DOC content of the studied matrices was reduced by 6-22%, with a maximum process efficacy being achieved with 3.0 mg O3/mg DOC. Ozonation also lead to changes in the NOM structure, i.e. complete oxidation of the humic acid fractions in both investigated matrices. After oxidation, hydrophilic structures dominate the natural water matrix (65%, whereas the synthetic matrix has an equal distribution of hydrophobic and hydrophilic fractions (~50%. Changes in the content and structure of NOM during ozonation resulted in the reduction of the total HAA precursors content (63-85%, using 3.0 mg O3/mg DOC. Detailed analysis of the reactivity of the residual HAA precursor materials shows that ozonation using 3.0 mg O3/mg DOC reduced the reactivity of the NOM fractions in comparison to the raw water. By contrast, HAA precursor material present in the commercial HA solution was transformed after ozonation into other reactive compounds, i.e. precursors which originated from the fulvic acid and hydrophilic fractions. The results of the laboratory testing indicate that the

  8. Low modeled ozone production suggests underestimation of precursor emissions (especially NOx) in Europe

    Science.gov (United States)

    Oikonomakis, Emmanouil; Aksoyoglu, Sebnem; Ciarelli, Giancarlo; Baltensperger, Urs; Prévôt, André Stephan Henry

    2018-02-01

    High surface ozone concentrations, which usually occur when photochemical ozone production takes place, pose a great risk to human health and vegetation. Air quality models are often used by policy makers as tools for the development of ozone mitigation strategies. However, the modeled ozone production is often not or not enough evaluated in many ozone modeling studies. The focus of this work is to evaluate the modeled ozone production in Europe indirectly, with the use of the ozone-temperature correlation for the summer of 2010 and to analyze its sensitivity to precursor emissions and meteorology by using the regional air quality model, the Comprehensive Air Quality Model with Extensions (CAMx). The results show that the model significantly underestimates the observed high afternoon surface ozone mixing ratios (≥ 60 ppb) by 10-20 ppb and overestimates the lower ones (degradation of the model performance for the lower ozone mixing ratios. The model performance for ozone-temperature correlation is also better when NOx emissions are doubled. In the Benelux area, however, the third scenario (where both NOx and VOC emissions are increased) leads to a better model performance. Although increasing only the traffic NOx emissions by a factor of 4 gave very similar results to the doubling of all NOx emissions, the first scenario is more consistent with the uncertainties reported by other studies than the latter, suggesting that high uncertainties in NOx emissions might originate mainly from the road-transport sector rather than from other sectors. The impact of meteorology was examined with three sensitivity tests: (i) increased surface temperature by 4 °C, (ii) reduced wind speed by 50 % and (iii) doubled wind speed. The first two scenarios led to a consistent increase in all surface ozone mixing ratios, thus improving the model performance for the high ozone values but significantly degrading it for the low ozone values, while the third scenario had exactly the

  9. Effect of regional precursor emission controls on long-range ozone transport – Part 2: Steady-state changes in ozone air quality and impacts on human mortality

    Directory of Open Access Journals (Sweden)

    J. J. West

    2009-08-01

    Full Text Available Large-scale changes in ozone precursor emissions affect ozone directly in the short term, and also affect methane, which in turn causes long-term changes in ozone that affect surface ozone air quality. Here we assess the effects of changes in ozone precursor emissions on the long-term change in surface ozone via methane, as a function of the emission region, by modeling 10% reductions in anthropogenic nitrogen oxide (NOx emissions from each of nine world regions. Reductions in NOx emissions from all world regions increase methane and long-term surface ozone. While this long-term increase is small compared to the intra-regional short-term ozone decrease, it is comparable to or larger than the short-term inter-continental ozone decrease for some source-receptor pairs. The increase in methane and long-term surface ozone per ton of NOx reduced is greatest in tropical and Southern Hemisphere regions, exceeding that from temperate Northern Hemisphere regions by roughly a factor of ten. We also assess changes in premature ozone-related human mortality associated with regional precursor reductions and long-range transport, showing that for 10% regional NOx reductions, the strongest inter-regional influence is for emissions from Europe affecting mortalities in Africa. Reductions of NOx in North America, Europe, the Former Soviet Union, and Australia are shown to reduce more mortalities outside of the source regions than within. Among world regions, NOx reductions in India cause the greatest number of avoided mortalities per ton, mainly in India itself. Finally, by increasing global methane, NOx reductions in one hemisphere tend to cause long-term increases in ozone concentration and mortalities in the opposite hemisphere. Reducing emissions of methane, and to a lesser extent carbon monoxide and non-methane volatile organic compounds, alongside NOx reductions would

  10. Towards the retrieval of tropospheric ozone with the ozone monitoring instrument (OMI)

    NARCIS (Netherlands)

    Mielonen, T.; De Haan, J.F.; Van Peet, J.C.A.; Eremenko, M.; Veefkind, J.P.

    2015-01-01

    We have assessed the sensitivity of the operational Ozone Monitoring Instrument (OMI) ozone profile retrieval algorithm to a number of a priori and radiative transfer assumptions. We studied the effect of stray light correction, surface albedo assumptions and a priori ozone profiles on the retrieved

  11. Evaluation of Global Ozone Monitoring Experiment (GOME) ozone profiles from nine different algorithms

    NARCIS (Netherlands)

    Meijer, Y.J.; Swart, D.P.J.; Baier, F.; Bhartia, P.K.; Bodeker, G.E.; Casadio, S.; Chance, K.; Frate, Del F.; Erbertseder, T.; Felder, M.D.; Flynn, L.E.; Godin-Beekmann, S.; Hansen, G.; Hasekamp, O.P.; Kaifel, A.; Kelder, H.M.; Kerridge, B.J.; Lambert, J.-C.; Landgraf, J.; Latter, B.G.; Liu, X.; McDermid, I.S.; Pachepsky, Y.; Rozanov, V.; Siddans, R.; Tellmann, S.; A, van der R.J.; Oss, van R.F.; Weber, M.; Zehner, C.

    2006-01-01

    An evaluation is made of ozone profiles retrieved from measurements of the nadir-viewing Global Ozone Monitoring Experiment (GOME) instrument. Currently, four different approaches are used to retrieve ozone profile information from GOME measurements, which differ in the use of external information

  12. Ozone Measurements Monitoring Using Data-Based Approach

    KAUST Repository

    Harrou, Fouzi; Kadri, Farid; Khadraoui, Sofiane; Sun, Ying

    2016-01-01

    The complexity of ozone (O3) formation mechanisms in the troposphere make the fast and accurate modeling of ozone very challenging. In the absence of a process model, principal component analysis (PCA) has been extensively used as a data-based monitoring technique for highly correlated process variables; however conventional PCA-based detection indices often fail to detect small or moderate anomalies. In this work, we propose an innovative method for detecting small anomalies in highly correlated multivariate data. The developed method combine the multivariate exponentially weighted moving average (MEWMA) monitoring scheme with PCA modelling in order to enhance anomaly detection performance. Such a choice is mainly motivated by the greater ability of the MEWMA monitoring scheme to detect small changes in the process mean. The proposed PCA-based MEWMA monitoring scheme is successfully applied to ozone measurements data collected from Upper Normandy region, France, via the network of air quality monitoring stations. The detection results of the proposed method are compared to that declared by Air Normand air monitoring association.

  13. Ozone Measurements Monitoring Using Data-Based Approach

    KAUST Repository

    Harrou, Fouzi

    2016-02-01

    The complexity of ozone (O3) formation mechanisms in the troposphere make the fast and accurate modeling of ozone very challenging. In the absence of a process model, principal component analysis (PCA) has been extensively used as a data-based monitoring technique for highly correlated process variables; however conventional PCA-based detection indices often fail to detect small or moderate anomalies. In this work, we propose an innovative method for detecting small anomalies in highly correlated multivariate data. The developed method combine the multivariate exponentially weighted moving average (MEWMA) monitoring scheme with PCA modelling in order to enhance anomaly detection performance. Such a choice is mainly motivated by the greater ability of the MEWMA monitoring scheme to detect small changes in the process mean. The proposed PCA-based MEWMA monitoring scheme is successfully applied to ozone measurements data collected from Upper Normandy region, France, via the network of air quality monitoring stations. The detection results of the proposed method are compared to that declared by Air Normand air monitoring association.

  14. Low modeled ozone production suggests underestimation of precursor emissions (especially NOx in Europe

    Directory of Open Access Journals (Sweden)

    E. Oikonomakis

    2018-02-01

    Full Text Available High surface ozone concentrations, which usually occur when photochemical ozone production takes place, pose a great risk to human health and vegetation. Air quality models are often used by policy makers as tools for the development of ozone mitigation strategies. However, the modeled ozone production is often not or not enough evaluated in many ozone modeling studies. The focus of this work is to evaluate the modeled ozone production in Europe indirectly, with the use of the ozone–temperature correlation for the summer of 2010 and to analyze its sensitivity to precursor emissions and meteorology by using the regional air quality model, the Comprehensive Air Quality Model with Extensions (CAMx. The results show that the model significantly underestimates the observed high afternoon surface ozone mixing ratios (≥  60 ppb by 10–20 ppb and overestimates the lower ones (<  40 ppb by 5–15 ppb, resulting in a misleading good agreement with the observations for average ozone. The model also underestimates the ozone–temperature regression slope by about a factor of 2 for most of the measurement stations. To investigate the impact of emissions, four scenarios were tested: (i increased volatile organic compound (VOC emissions by a factor of 1.5 and 2 for the anthropogenic and biogenic VOC emissions, respectively, (ii increased nitrogen oxide (NOx emissions by a factor of 2, (iii a combination of the first two scenarios and (iv increased traffic-only NOx emissions by a factor of 4. For southern, eastern, and central (except the Benelux area Europe, doubling NOx emissions seems to be the most efficient scenario to reduce the underestimation of the observed high ozone mixing ratios without significant degradation of the model performance for the lower ozone mixing ratios. The model performance for ozone–temperature correlation is also better when NOx emissions are doubled. In the Benelux area, however, the third scenario

  15. Impacts of increasing ozone on Indian plants

    International Nuclear Information System (INIS)

    Oksanen, E.; Pandey, V.; Pandey, A.K.; Keski-Saari, S.; Kontunen-Soppela, S.; Sharma, C.

    2013-01-01

    Increasing anthropogenic and biogenic emissions of precursor compounds have led to high tropospheric ozone concentrations in India particularly in Indo-Gangetic Plains, which is the most fertile and cultivated area of this rapidly developing country. Current ozone risk models, based on European and North American data, provide inaccurate estimations for crop losses in India. During the past decade, several ozone experiments have been conducted with the most important Indian crop species (e.g. wheat, rice, mustard, mung bean). Experimental work started in natural field conditions around Varanasi area in early 2000's, and the use of open top chambers and EDU (ethylene diurea) applications has now facilitated more advanced studies e.g. for intra-species sensitivity screening and mechanisms of tolerance. In this review, we identify and discuss the most important gaps of knowledge and future needs of action, e.g. more systematic nationwide monitoring for precursor and ozone formation over Indian region. -- Tropospheric ozone is an increasing threat to food production in India

  16. In Brief: Monitoring ozone in Qatar

    Science.gov (United States)

    Showstack, Randy

    2008-12-01

    Qatar is establishing an ozone and pollution monitoring ground station in West Asia, following discussions between the government, the Qatar Foundation, and the United Nations Environment Programme, according to a 19 November announcement. The station will assist in understanding whether the ozone layer is actually recovering after being damaged by ozone-depleting chemicals. Qatar also announced plans to establish a global center of excellence for research and development of ozone and climate-friendly technology, equipment, and appliances. UNEP executive director Achim Steiner said the announcements by Qatar ``will help plug key data gaps relating to information gathering in West Asia and the Gulf to the benefit of the region and the world.''

  17. The ozone monitoring instrument

    NARCIS (Netherlands)

    Levelt, P.F.; Oord, G.H.J. van den; Dobber, M.R.; Mälkki, A.; Visser, H.; Vries, J. de; Stammes, P.; Lundell, J.O.V.; Saari, H.

    2006-01-01

    The Ozone Monitoring Instrument (OMI) flies on the National Aeronautics and Space Adminsitration's Earth Observing System Aura satellite launched in July 2004. OMI is a ultraviolet/visible (UV/VIS) nadir solar backscatter spectrometer, which provides nearly global coverage in one day with a spatial

  18. OZONE CONCENTRATION ATTRIBUTABLE PREMATURE DEATH IN POLAND

    Directory of Open Access Journals (Sweden)

    Krzysztof Skotak

    2010-03-01

    Full Text Available Ozone in the lower part of the atmosphere (troposphere, strong photochemical oxidant, is not directly emitted to the atmosphere but formed through a series of complex reactions. Ozone concentrations depends on ozone precursors air contamination (mainly nitrogen dioxide and non-methane volatile organic compounds and meteorological conditions (temperature and solar radiation. The main sectors emitted ozone precursors are road transport, power and heat generation plants, household (heating, industry, and petrol storage and distribution. Ozone and some of its precursors are also transported long distances in the atmosphere and are therefore considered a transboundary problem. As a result, the ozone concentrations are often low in busy urban areas and higher in suburban and rural areas. Nowadays, instead of particulate matter, ozone is one of the most widespread global air pollution problems. In and around urban areas, relatively large gradients of ozone can be observed. Because of its high reactivity in elevated concentrations ozone causes serious health problems and damage to ecosystems, agricultural crops and materials. Main ill-health endpoints as a results of ozone concentrations can be characterised as an effect of pulmonary and cardiovascular system, time morbidity and mortality series, development of atherosclerosis and asthma and finally reduction in life expectancy. The associations with increased daily mortality due to ozone concentrations are confirmed by many researches and epidemiological studies. Estimation of the level selected ill-health endpoints (mortality in total and due to cardiovascular and respiratory causes as a result of the short-term ozone exposure in Poland was the main aim of the project. Final results have been done based on estimation method elaborated by WHO, ozone measurements from National Air Quality Monitoring System and statistical information such as mortality rate and populations. All analysis have been done in

  19. National Plan for Stratospheric Ozone Monitoring and Early Detection of Change, 1981-1986

    International Nuclear Information System (INIS)

    1982-02-01

    A transition from reliance on a ground-based, geographically-biased ozone observing network operated by cooperating nations to a combined satellite and ground-based monitoring program that will provide global coverage of the vertical distribution of stratospheric ozone, as well as total ozone overburden is discussed. The strategy, instrumentation, and monitoring products to be prepared during this transition period are also discussed. Global atmospheric monitoring for protection of the ultraviolet shielding properties of atmospheric ozone is considered. The operational satellite ozone vertical profile monitoring system to be flown on the NOAA Tiros N operational satellite series to carry on ozone measurements initiated on the NASA R D satellites is also considered

  20. Future heat waves and surface ozone

    Science.gov (United States)

    Meehl, Gerald A.; Tebaldi, Claudia; Tilmes, Simone; Lamarque, Jean-Francois; Bates, Susan; Pendergrass, Angeline; Lombardozzi, Danica

    2018-06-01

    A global Earth system model is used to study the relationship between heat waves and surface ozone levels over land areas around the world that could experience either large decreases or little change in future ozone precursor emissions. The model is driven by emissions of greenhouse gases and ozone precursors from a medium-high emission scenario (Representative Concentration Pathway 6.0–RCP6.0) and is compared to an experiment with anthropogenic ozone precursor emissions fixed at 2005 levels. With ongoing increases in greenhouse gases and corresponding increases in average temperature in both experiments, heat waves are projected to become more intense over most global land areas (greater maximum temperatures during heat waves). However, surface ozone concentrations on future heat wave days decrease proportionately more than on non-heat wave days in areas where ozone precursors are prescribed to decrease in RCP6.0 (e.g. most of North America and Europe), while surface ozone concentrations in heat waves increase in areas where ozone precursors either increase or have little change (e.g. central Asia, the Mideast, northern Africa). In the stabilized ozone precursor experiment, surface ozone concentrations increase on future heat wave days compared to non-heat wave days in most regions except in areas where there is ozone suppression that contributes to decreases in ozone in future heat waves. This is likely associated with effects of changes in isoprene emissions at high temperatures (e.g. west coast and southeastern North America, eastern Europe).

  1. Accuracy and practicality of a portable ozone monitor for personal exposure estimates

    Science.gov (United States)

    Sagona, Jessica A.; Weisel, Clifford P.; Meng, Qingyu

    2018-02-01

    Accurate measurements of personal exposure to atmospheric pollutants such as ozone are important for understanding health risks. We tested a new personal ozone monitor (POM; 2B Technologies) for accuracy, precision, and ease of use. The POM's measurements were compared to simultaneous ozone measurements from a 2B Model 205 monitor and a ThermoScientific 49i monitor, and multiple POMs were placed side-by-side to check precision. Tests were undertaken in a controlled environmental facility, outdoors, and in a private residence. Additionally, ten volunteers wore a POM for five days and answered a questionnaire about its ease of use. The POM measured ozone accurately compared to the 49i ozone monitor, with average relative differences of less than 8%. In the controlled environment tests, the POM's ozone measurements did not change in the presence of additional atmospheric constituents with similar absorption lines to ozone, though there may have been a small decrease in precision and accuracy. Precision between POMs varied by environment (r2 = 0.98 outdoors; r2 = 0.3 to 0.9 in controlled lab conditions). Volunteers reported that the POM was reasonably comfortable to wear, although all reported that they felt that it was too noisy. Overall, the POM is a viable option for personal ozone monitoring.

  2. Medium-range mid-tropospheric transport of ozone and precursors over Africa: two numerical case studies in dry and wet seasons

    Directory of Open Access Journals (Sweden)

    B. Sauvage

    2007-10-01

    Full Text Available A meso-scale model was used to understand and describe the dynamical processes driving high ozone concentrations observed during both dry and monsoon season in monthly climatologies profiles over Lagos (Nigeria, 6.6° N, 3.3° E, obtained with the MOZAIC airborne measurements (ozone and carbon monoxide. This study focuses on ozone enhancements observed in the upper-part of the lower troposphere, around 3000 m. Two individual cases have been selected in the MOZAIC dataset as being representative of the climatological ozone enhancements, to be simulated and analyzed with on-line Lagrangian backtracking of air masses.

    This study points out the role of baroclinic low-level circulations present in the Inter Tropical Front (ITF area. Two low-level thermal cells around a zonal axis and below 2000 m, in mirror symmetry to each other with respect to equator, form near 20° E and around 5° N and 5° S during the (northern hemisphere dry and wet seasons respectively. They are caused by surface gradients – the warm dry surface being located poleward of the ITF and the cooler wet surface equatorward of the ITF.

    A convergence line exists between the poleward low-level branch of each thermal cell and the equatorward low-level branch of the Hadley cell. Our main conclusion is to point out this line as a preferred location for fire products – among them ozone precursors – to be uplifted and injected into the lower free troposphere.

    The free tropospheric transport that occurs then depends on the hemisphere and season. In the NH dry season, the AEJ allows transport of ozone and precursors westward to Lagos. In the NH monsoon (wet season, fire products are transported from the southern hemisphere to Lagos by the southeasterly trade that surmounts the monsoon layer. Additionally ozone precursors uplifted by wet convection in the ITCZ can also mix to the ones uplifted by the baroclinic cell and be advected up to Lagos by the trade

  3. Effect of regional precursor emission controls on long-range ozone transport – Part 1: Short-term changes in ozone air quality

    Directory of Open Access Journals (Sweden)

    J. J. West

    2009-08-01

    Full Text Available Observations and models demonstrate that ozone and its precursors can be transported between continents and across oceans. We model the influences of 10% reductions in anthropogenic nitrogen oxide (NOx emissions from each of nine world regions on surface ozone air quality in that region and all other regions. In doing so, we quantify the relative importance of long-range transport between all source-receptor pairs, for direct short-term ozone changes. We find that for population-weighted concentrations during the three-month "ozone-season", the strongest inter-regional influences are from Europe to the Former Soviet Union, East Asia to Southeast Asia, and Europe to Africa. The largest influences per unit of NOx reduced, however, are seen for source regions in the tropics and Southern Hemisphere, which we attribute mainly to greater sensitivity to changes in NOx in the lower troposphere, and secondarily to increased vertical convection to the free troposphere in tropical regions, allowing pollutants to be transported further. Results show, for example, that NOx reductions in North America are ~20% as effective per unit NOx in reducing ozone in Europe during summer, as NOx reductions from Europe itself. Reducing anthropogenic emissions of non-methane volatile organic compounds (NMVOCs and carbon monoxide (CO by 10% in selected regions, can have as large an impact on long-range ozone transport as NOx reductions, depending on the source region. We find that for many source-receptor pairs, the season of greatest long-range influence does not coincide with the season when ozone is highest in the receptor region. Reducing NOx emissions in most source regions causes a larger decrease in export of ozone from the source region than in ozone production outside of the source region.

  4. Ozone production in summer in the megacities of Tianjin and Shanghai, China: a comparative study

    Directory of Open Access Journals (Sweden)

    L. Ran

    2012-08-01

    Full Text Available Rapid economic growth has given rise to a significant increase in ozone precursor emissions in many regions of China, especially in the densely populated North China Plain (NCP and Yangtze River Delta (YRD. Improved understanding of ozone formation in response to different precursor emissions is imperative to address the highly nonlinear ozone problem and to provide a solid scientific basis for efficient ozone abatement in these regions. A comparative study on ozone photochemical production in summer has thus been carried out in the megacities of Tianjin (NCP and Shanghai (YRD. Two intensive field campaigns were carried out respectively at an urban and a suburban site of Tianjin, in addition to routine monitoring of trace gases in Shanghai, providing data sets of surface ozone and its precursors including nitrogen oxides (NOx and various non-methane hydrocarbons (NMHCs. Ozone pollution in summer was found to be more severe in the Tianjin region than in the Shanghai region, based on either the frequency or the duration of high ozone events. Such differences might be attributed to the large amount of highly reactive NMHCs in Tianjin. Industry related species like light alkenes were of particular importance in both urban and suburban Tianjin, while in Shanghai aromatics dominated. In general, the ozone problem in Shanghai is on an urban scale. Stringent control policies on local emissions would help reduce the occurrence of high ozone concentrations. By contrast, ozone pollution in Tianjin is probably a regional problem. Combined efforts to reduce ozone precursor emissions on a regional scale must be undertaken to bring the ozone problem under control.

  5. Monitoring of the atmospheric ozone layer and natural ultraviolet radiation: Annual report 2011

    Energy Technology Data Exchange (ETDEWEB)

    Svendby, T.M.; Myhre, C.L.; Stebel, K.; Edvardsen, K; Orsolini, Y.; Dahlback, A.

    2012-07-01

    This is an annual report describing the activities and main results of the monitoring programme: Monitoring of the atmospheric ozone layer and natural ultraviolet radiation for 2011. 2011 was a year with generally low ozone values above Norway. A clear decrease in the ozone layer above Norway during the period 1979-1997 stopped after 1998 and the ozone layer above Norway seems now to have stabilized.(Author)

  6. Source attribution of tropospheric ozone

    Science.gov (United States)

    Butler, T. M.

    2015-12-01

    Tropospheric ozone is a harmful pollutant with adverse effects on human health and ecosystems. As well as these effects, tropospheric ozone is also a powerful greenhouse gas, with an anthropogenic radiative forcing one quarter of that of CO2. Along with methane and atmospheric aerosol, tropospheric ozone belongs to the so-called Short Lived Climate forcing Pollutants, or SLCP. Recent work has shown that efforts to reduce concentrations of SLCP in the atmosphere have the potential to slow the rate of near-term climate change, while simultaneously improving public health and reducing crop losses. Unlike many other SLCP, tropospehric ozone is not directly emitted, but is instead influenced by two distinct sources: transport of air from the ozone-rich stratosphere; and photochemical production in the troposphere from the emitted precursors NOx (oxides of nitrogen), CO (Carbon Monoxide), and VOC (volatile organic compounds, including methane). Better understanding of the relationship between ozone production and the emissions of its precursors is essential for the development of targeted emission reduction strategies. Several modeling methods have been employed to relate the production of tropospheric ozone to emissions of its precursors; emissions perturbation, tagging, and adjoint sensitivity methods all deliver complementary information about modelled ozone production. Most studies using tagging methods have focused on attribution of tropospheric ozone production to emissions of NOx, even though perturbation methods have suggested that tropospheric ozone is also sensitive to VOC, particularly methane. In this study we describe the implementation into a global chemistry-climate model of a scheme for tagging emissions of NOx and VOC with an arbitrary number of labels, which are followed through the chemical reactions of tropospheric ozone production in order to perform attribution of tropospehric ozone to its emitted precursors. Attribution is performed to both

  7. Ozone pollution: rising concentrations despite French and EU efforts

    International Nuclear Information System (INIS)

    Ba, M.; Elichegaray, Ch.

    2003-11-01

    Ozone is the main indicator of photochemical pollution which is caused by a complex combination of primary pollutants formed by chemical reactions in the troposphere, in the presence of sunlight. These primary pollutants, otherwise known as precursors of ozone (nitrogen oxides, volatile organic compounds and carbon monoxide), are emitted both by natural sources and human activities. In urban areas, during the summer months, ozone is often the main cause of deterioration in air quality. Directive 2002/3/EC relating to ozone in ambient air entered into force on 9 September 2003, superseding the first ozone Directive (92/72/CE) of 21 September 1992. In the last 10 years, monitoring of ozone pollution has considerably progressed in France (the number of analysers has increased tenfold). Emissions of the ozone precursors fell significantly (-27%) between 1990 and 2000 in France as a result of combined efforts in all sectors of activity. However, between 1994 and 2002, ozone levels remained above the information threshold for the protection of human health and vegetation on average more than 100 days a year in rural areas and over 40 days a year in urban and peri-urban areas. Efforts undertaken both in France and other European countries aim to improve the situation and ensure compliance with the requirements of Directive 2002/3/EC. (author)

  8. Tropospheric ozone column retrieval at northern mid-latitudes from the Ozone Monitoring Instrument by means of a neural network algorithm

    Directory of Open Access Journals (Sweden)

    P. Sellitto

    2011-11-01

    Full Text Available Monitoring tropospheric ozone from space is of critical importance in order to gain more thorough knowledge on phenomena affecting air quality and the greenhouse effect. Deriving information on tropospheric ozone from UV/VIS nadir satellite spectrometers is difficult owing to the weak sensitivity of the measured radiance spectra to variations of ozone in the troposphere. Here we propose an alternative method of analysis to retrieve tropospheric ozone columns from Ozone Monitoring Instrument radiances by means of a neural network algorithm. An extended set of ozone sonde measurements at northern mid-latitudes for the years 2004–2008 has been considered as the training and test data set. The design of the algorithm is extensively discussed. Our retrievals are compared to both tropospheric ozone residuals and optimal estimation retrievals over a similar independent test data set. Results show that our algorithm has comparable accuracy with respect to both correlative methods and its performance is slightly better over a subset containing only European ozone sonde stations. Possible sources of errors are analyzed. Finally, the capabilities of our algorithm to derive information on boundary layer ozone are studied and the results critically discussed.

  9. Monitoring the consequences of decreased ozone protection: The NSF ultraviolet radiation monitoring network

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    The effects of decreased protection from ultraviolet radiation are as troubling as the continuing depletion of stratospheric ozone. Evidence exists to clearly link ozone depletion to changes in the antarctic marine environment. Results of two 1992 papers are summarized here. Enhanced exposure to mid-range UV radiation was found to be affecting marine ecosystems with a recorded 6-12 percent reduction in primary productivity directly related to the ozone layer depletion. In another experiment, a model was developed indicating that the ozone hole could reduce near-surface photosynthesis by as much as 12-15 percent. The NSF UV monitoring system in place for these and other experiments uses a spectroradiometer, making hourly, high-resolution measurements of the distribution of UV surface irradiance

  10. Chemical Evolution of Ozone and Its Precursors in Asian Pacific Rim Outflow During TRACE-P

    Science.gov (United States)

    Hamlin, A.; Crawford, J.; Olson, J.; Pippin, M.; Avery, M.; Sachse, G.; Barrick, J.; Blake, D.; Tan, D.; Sandholm, S.; Kondo, Y.; Singh, H.; Eisele, F.; Zondlo, M.; Flocke, F.; Talbot, R.

    2002-12-01

    During NASA's GTE/TRACE-P (Transport and Chemical Evolution over the Pacific) mission, a widespread stagnant pollution layer was observed between 2 and 4 km over the central Pacific. In this region, high levels of O3 (70~ppbv), CO (210~ppbv), and NOx (130~pptv) were observed. Back trajectories suggest this airmass had been rapidly transported from the Asian coast near the Yellow Sea to the central Pacific where it underwent subsidence. The chemical evolution of ozone and its precursors for this airmass is examined using lagrangian photochemical box model calculations. Simulations are conducted along trajectories which intersect the flight path where predicted mixing ratios are compared to measurements. An analysis of the photochemical processes controlling the cycling of nitrogen oxides and ozone production and destruction during transport will be presented.

  11. Distribution of ozone and its precursors over Bay of Bengal during winter 2009: role of meteorology

    Directory of Open Access Journals (Sweden)

    L. M. David

    2011-09-01

    Full Text Available Measurements of ozone and NO2 were carried out in the marine environment of the Bay of Bengal (BoB during the winter months, December 2008–January 2009, as part of the second Integrated Campaign for Aerosols, gases and Radiation Budget conducted under the Geosphere Biosphere Programme of the Indian Space Research Organization. The ozone mixing ratio was found to be high in the head and the southeast BoB with a mean value of 61 ± 7 ppb and 53 ± 6 ppb, respectively. The mixing ratios of NO2 and CO were also relatively high in these regions. The spatial patterns were examined in the light of airflow patterns, air mass back trajectories and other meteorological conditions and satellite retrieved maps of tropospheric ozone, NO2, CO, and fire count in and around the region. The distribution of these gases was strongly associated with the transport from the adjoining land mass. The anthropogenic activities and forest fires/biomass burning over the Indo Gangetic Plains and other East Asian regions contribute to ozone and its precursors over the BoB. Similarity in the spatial pattern suggests that their source regions could be more or less the same. Most of the diurnal patterns showed decrease of the ozone mixing ratio during noon/afternoon followed by a nighttime increase and a morning high. Over this oceanic region, photochemical production of ozone involving NO2 was not very active. Water vapour played a major role in controlling the variation of ozone. An attempt is made to simulate ozone level over the north and south BoB using the photochemical box model (NCAR-MM. The present observed features were compared with those measured during the earlier cruises conducted in different seasons.

  12. N-nitrosodimethylamine (NDMA) formation from the ozonation of model compounds.

    Science.gov (United States)

    Marti, Erica J; Pisarenko, Aleksey N; Peller, Julie R; Dickenson, Eric R V

    2015-04-01

    Nitrosamines are a class of toxic disinfection byproducts commonly associated with chloramination, of which several were included on the most recent U.S. EPA Contaminant Candidate List. Nitrosamine formation may be a significant barrier to ozonation in water reuse applications, particularly for direct or indirect potable reuse, since recent studies show direct formation during ozonation of natural water and treated wastewaters. Only a few studies have identified precursors which react with ozone to form N-nitrosodimethylamine (NDMA). In this study, several precursor compound solutions, prepared in ultrapure water and treated wastewater, were subjected to a 10 M excess of ozone. In parallel experiments, the precursor solutions in ultrapure water were exposed to gamma radiation to determine NDMA formation as a byproduct of reactions of precursor compounds with hydroxyl radicals. The results show six new NDMA precursor compounds that have not been previously reported in the literature, including compounds with hydrazone and carbamate moieties. Molar yields in deionized water were 61-78% for 3 precursors, 12-23% for 5 precursors and NDMA formation for the other precursors. NDMA formation due to chloramination was minimal compared to formation due to ozonation, suggesting distinct groups of precursor compounds for these two oxidants. Hydroxyl radical reactions with the precursors will produce NDMA, but formation is much greater in the presence of molecular ozone. Also, hydroxyl radical scavenging during ozonation leads to increased NDMA formation. Molar conversion yields were higher for several precursors in wastewater as compared to deionized water, which could be due to catalyzed reactions with constituents found in wastewater or hydroxyl radical scavenging. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Observing Tropospheric Ozone From Space

    Science.gov (United States)

    Fishman, Jack

    2000-01-01

    The importance of tropospheric ozone embraces a spectrum of relevant scientific issues ranging from local environmental concerns, such as damage to the biosphere and human health, to those that impact global change questions, Such is climate warming. From an observational perspective, the challenge is to determine the tropospheric ozone global distribution. Because its lifetime is short compared with other important greenhouse gases that have been monitored over the past several decades, the distribution of tropospheric ozone cannot be inferred from a relatively small set of monitoring stations. Therefore, the best way to obtain a true global picture is from the use of space-based instrumentation where important spatial gradients over vast ocean expanses and other uninhabited areas can be properly characterized. In this paper, the development of the capability to measure tropospheric ozone from space over the past 15 years is summarized. Research in the late 1980s successfully led to the determination of the climatology of tropospheric ozone as a function of season; more recently, the methodology has improved to the extent where regional air pollution episodes can be characterized. The most recent modifications now provide quasi-global (50 N) to 50 S) maps on a daily basis. Such a data set would allow for the study of long-range (intercontinental) transport of air pollution and the quantification of how regional emissions feed into the global tropospheric ozone budget. Future measurement capabilities within this decade promise to offer the ability to provide Concurrent maps of the precursors to the in situ formation of tropospheric ozone from which the scientific community will gain unprecedented insight into the processes that control global tropospheric chemistry

  14. The study of international and interstate transport of ozone in Yuma, Arizona

    Science.gov (United States)

    Li, Y.; Sonenberg, M.; Wood, J. L.; Pearson, C. R.; Colson, H.; Malloy, J. W.; Pace, M.; Mao, F.; Paul, J.; Busby, B. R.; Parkey, B.; Drago, L.; Franquist, T. S.

    2017-12-01

    In October 2015, EPA reduced the National Ambient Air Quality Standards (NAAQS) for ozone from 75 parts per billion (ppb) to 70 ppb. Meeting the new standard may be extremely challenging for some areas, including rural Yuma County in the State of Arizona. Yuma County faces unique air quality challenges, since it borders the Mexican states of Baja California and Sonora, and the State of California. The present study investigates the contribution of international and interstate transport of ozone and ozone precursors to episodes of elevated ozone concentrations in Yuma. The Arizona Department of Environmental Quality (ADEQ) merged HYSPLIT modeling outputs with two years of hourly ground ozone monitor data to investigate the potential area contributions to ozone concentrations in Yuma County. This analysis found that elevated ozone concentrations in Yuma in 2014 and 2015 frequently coincided with back-trajectories over both California and Mexico, typically favoring Mexico during the spring. In May 2017, ADEQ installed a new ozone monitor in San Luis Rio Colorado, Sonora, Mexico (Latitude: 32.4665, Longitude: -114.7688), which is 29 km south of ozone site in Yuma County. We will present the first simultaneous observations of ozone seasons in Sonora, Mexico, eastern California, and Yuma.

  15. Thermoluminescence as a tool for monitoring ozone-stressed plants

    Energy Technology Data Exchange (ETDEWEB)

    Skotnica, J.; Gilbert, M.; Weingart, I.; Wilhelm, C

    2003-05-01

    Thermoluminescence parameters are more sensitive to ozone than fluorescence parameters (F{sub 0}, F{sub M}, F{sub v}/F{sub M}). - The effect of ozone (6 h, various concentrations from 0 to 350 ppb) on barley (Hordeum vulgare L., cv. Bomi) and tomato (Lycopersicon esculentum L., cv. Yellow Cherry) leaves was investigated in parallel by thermoluminescence (TL) and fluorescence (FL) methods. Several significant changes were found in TL glow curves measured after excitation by one single turnover flash at +2 deg. C in the temperature range from 2 to 170 deg. C immediately after ozone exposure. Contrary to TL, ozone induced only negligible changes in FL parameters F{sub 0}, F{sub M} and F{sub v}/F{sub M}. Measurements done 24 h after ozone exposure showed partial recovery of ozone-induced changes. The extent of recovery was not the same in different parts of TL curves. Fluorescence parameters were not significantly changed. The results demonstrate that TL parameters are more sensitive to ozone than conventially used FL parameters F{sub 0}, F{sub M} and F{sub v}/F{sub M}. Moreover, TL measurements seem to give information not only about the PSII electron transport, but also about the extent of oxidative damage and membrane lipid peroxidation. It is concluded, that TL can be a highly informative tool for monitoring the impact of ozone on plants.

  16. Ozone response to emission changes: a modeling study during the MCMA-2006/MILAGRO Campaign

    Directory of Open Access Journals (Sweden)

    J. Song

    2010-04-01

    Full Text Available The sensitivity of ozone production to precursor emissions was investigated under five different meteorological conditions in the Mexico City Metropolitan Area (MCMA during the MCMA-2006/MILAGRO field campaign using the gridded photochemical model CAMx driven by observation-nudged WRF meteorology. Precursor emissions were constrained by the comprehensive data from the field campaign and the routine ambient air quality monitoring network. Simulated plume mixing and transport were examined by comparing with measurements from the G-1 aircraft during the campaign. The observed concentrations of ozone precursors and ozone were reasonably well reproduced by the model. The effects of reducing precursor emissions on urban ozone production were performed for three representative emission control scenarios. A 50% reduction in VOC emissions led to 7 to 22 ppb decrease in daily maximum ozone concentrations, while a 50% reduction in NOx emissions leads to 4 to 21 ppb increase, and 50% reductions in both NOx and VOC emission decrease the daily maximum ozone concentrations up to 10 ppb. These results along with a chemical indicator analysis using the chemical production ratios of H2O2 to HNO3 demonstrate that the MCMA urban core region is VOC-limited for all meteorological episodes, which is consistent with the results from MCMA-2003 field campaign; however the degree of the VOC-sensitivity is higher during MCMA-2006 due to lower VOCs, lower VOC reactivity and moderately higher NOx emissions. Ozone formation in the surrounding mountain/rural area is mostly NOx-limited, but can be VOC-limited, and the range of the NOx-limited or VOC-limited areas depends on meteorology.

  17. Measurements of ozone and its precursors in Beijing in summer

    Science.gov (United States)

    Lee, J. D.; Squires, F. A.; Dunmore, R.; Hamilton, J. F.; Hopkins, J. R.; Rickard, A. R.

    2017-12-01

    Over the past few years there have been substantial reductions in emission of primary pollutants (e.g. PM, NOx) in Beijing. However, levels of ozone (O3), which is produced from VOCs and NOxin the presence of sunlight, frequently break recommended exposure limits in Beijing and other large conurbations in China. In fact, it is suggested that ozone is likely to become the major air pollutant effecting human health in Beijing over the next 5-10 years. For 5 weeks in May and June 2017 O3 was measured, along with NOx, CO and a large range of VOCs (C2 - C13) at the Institute of Atmospheric Physics of the Chinese Academy of Sciences site, close to the 4th ring road in central Beijing. Elevated levels of O3 were regularly observed, with maximum concentrations of 180 ppbv. On 75% of days during this period, O3 breached the recommended WHO 8 hour exposure limit of 60 ppbv. Data will be presented showing the effect of different levels of precursor species and photolysis rates on O3. The peak concentration of O3 on each day seemed to have little correlation with NOx. Typically NO concentrations were elevated during the morning but often decreased to below 35oC meaning biogenic emissions also influenced the chemistry at the site, with several ppbv of isoprene measured during the afternoons. The importance of different VOCs for in-situ O3 formation is investigated using a simple steady state analysis of OH reactivity, along with a more detailed analysis using the Master Chemical Mechanism.

  18. Surface Monitoring Data for PM2.5 and Ozone

    Data.gov (United States)

    Washington University St Louis — AIRNOW is an EPA program in collaboration with the States to gather and distribute hourly near-realtime data from several hundred continuous PM2.5 and ozone monitors.

  19. Contribution of ozone to airborne aldehyde formation in Paris homes.

    Science.gov (United States)

    Rancière, Fanny; Dassonville, Claire; Roda, Célina; Laurent, Anne-Marie; Le Moullec, Yvon; Momas, Isabelle

    2011-09-15

    Indoor aldehydes may result from ozone-initiated chemistry, mainly documented by experimental studies. As part of an environmental investigation included in the PARIS birth cohort, the aim of this study was to examine ozone contribution to airborne aldehyde formation in Paris homes. Formaldehyde, acetaldehyde and hexaldehyde levels, as well as styrene, nitrogen dioxide and nicotine concentrations, comfort parameters and carbon dioxide levels, were measured twice during the first year of life of the babies. Ambient ozone concentrations were collected from the closest background station of the regional air monitoring network. Traffic-related nitrogen oxide concentrations in front of the dwellings were estimated by an air pollution dispersion model. Home characteristics and families' way of life were described by questionnaires. Stepwise multiple linear regression models were used to link aldehyde levels with ambient ozone concentrations and a few aldehyde precursors involved in oxidation reactions, adjusting for other indoor aldehyde sources, comfort parameters and traffic-related nitrogen oxides. A 4 and 11% increase in formaldehyde and hexaldehyde levels was pointed out when 8-hour ozone concentrations increased by 20 μg/m(3). The influence of potential precursors such as indoor styrene level and frequent use of air fresheners, containing unsaturated volatile organic compounds as terpenes, was also found. Thus, our results suggest that ambient ozone can significantly impact indoor air quality, especially with regard to formaldehyde and hexaldehyde levels. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. Ozone and atmospheric pollution at synoptic scale: the monitoring network Paes

    International Nuclear Information System (INIS)

    Gheusi, F.; Chevalier, A.; Delmas, R.; Athier, G.; Bouchou, P.; Cousin, J.M.; Meyerfeld, Y.; Laj, P.; Sellegri, K.; Ancellet, G.

    2007-01-01

    Ozone as an environmental concern extends beyond the questions usually covered by media - stratospheric ozone depletion and urban pollution peaks. Strong expositions to this pollutant are frequent even far from pollution sources, and the background tropospheric content of ozone has been growing fivefold over the last century. In response to this concern at the French national scale, formerly independent monitoring stations have been coordinated since 2004 in a structured network: Paes (French acronym for atmospheric pollution at synoptic scale). The data are put in free access online. (authors)

  1. An ozone episode over the Pearl River Delta in October 2008

    Science.gov (United States)

    Shen, Jin; Zhang, Yuanhang; Wang, Xuesong; Li, Jinfeng; Chen, Hao; Liu, Run; Zhong, Liuju; Jiang, Ming; Yue, Dingli; Chen, Duohong; Lv, Wei

    2015-12-01

    The north and east Pearl River Delta (PRD) is usually a clean, upwind area in autumn. Serious ozone pollution there in mid-late October 2008 was first discovered and then analyzed. Trajectory analysis, process analysis, ozone source apportionment technology, and sensitivity analysis were used to study this episode. Under the influence of a weak south wind, the precursors emitted in Guangzhou and Foshan were transported to the north and northeast PRD and formed ozone there, which resulted in high ozone concentration (>100 ppb). As the wind direction later transited to northerly, the precursors in the northeast PRD that originated from the central and west PRD were transported to the south, and caused severe ozone pollution in the southeast PRD. The ozone contributed by chemical processes reached >20 ppb/h in Jinguowan. More than 40 ppb ozone was contributed by the precursor emission in the central and west PRD during the episode. The ozone concentration was highly sensitive to the precursor emission in the PRD region in the high-ozone situations. This episode showed the complexity of regional pollution in the PRD. When the PRD is controlled by a low air pressure system and then cold air moves from northern China to the south, the risk of ozone pollution in the north and southeast PRD increases.

  2. Effective cloud fractions from the Ozone Monitoring Instrument: theoretical framework and validation

    NARCIS (Netherlands)

    Stammes, P.; Sneep, M.; Haan, de J.F.; Veefkind, J.P.; Wang, P.; Levelt, P.F.

    2008-01-01

    The Dutch-Finnish Ozone Monitoring Instrument (OMI) on board NASA's EOS-Aura satellite is measuring ozone, NO2, and other trace gases with daily global coverage. To correct these trace gas retrievals for the presence of clouds, there are two OMI cloud products, based on different physical processes,

  3. Sampling Ozone Exposure of Canadian Forests at Different Scales: Some Case Studies

    Directory of Open Access Journals (Sweden)

    R.M. Cox

    2001-01-01

    Full Text Available The use of passive samplers in extensive monitoring, such as that used in national forest health monitoring plots, indicates that these devices are able to determine both spatial and temporal differences in ozone exposure of the plots. This allows for categorisation of the plots and the potential for cause-effect analysis of certain forest health responses. Forest exposure along a gradient of air pollution deposition demonstrates large variation in accumulated exposures. The efficacy of using passive samplers for in situ monitoring of forest canopy exposure was also demonstrated. The sampler data produced weak relationships with ozone values from the nearest �continuous� monitor, even though data from colocated samplers showed strong relationships. This spatial variation and the apparent effect of elevation on ozone exposure demonstrate the importance of topography and tree canopy characteristics in plant exposure on a regional scale. In addition, passive sampling may identify the effects of local pollutant gases, such as NO, which may scavenge ozone locally only to increase the production of this secondary pollutant downwind, as atmospheric reactions redress the equilibrium between concentrations of this precursor and those of the generated ozone. The use of passive samplers at the stand level is able to resolve vertical profiles within the stand and edge effects that are important in exposure of understorey and ground flora. Recent case studies using passive samplers to determine forest exposure to ozone indicate a great potential for the development of spatial models on a regional, landscape, and stand level scale.

  4. "OZONE SOURCE APPORTIONMENT IN CMAQ' | Science ...

    Science.gov (United States)

    Ozone source attribution has been used to support various policy purposes including interstate transport (Cross State Air Pollution Rule) by U.S. EPA and ozone nonattainment area designations by State agencies. Common scientific applications include tracking intercontinental transport of ozone and ozone precursors and delineating anthropogenic and non-anthropogenic contribution to ozone in North America. As in the public release due in September 2013, CMAQ’s Integrated Source Apportionment Method (ISAM) attributes PM EC/OC, sulfate, nitrate, ammonium, ozone and its precursors NOx and VOC, to sectors/regions of users’ interest. Although the peroxide-to-nitric acid productions ratio has been the most common indicator to distinguish NOx-limited ozone production from VOC-limited one, other indicators are implemented in addition to allowing for an ensemble decision based on a total of 9 available indicator ratios. Moreover, an alternative approach of ozone attribution based on the idea of chemical sensitivity in a linearized system that has formed the basis of chemical treatment in forward DDM/backward adjoint tools has been implemented in CMAQ. This method does not require categorization into either ozone regime. In this study, ISAM will simulate the 2010 North America ozone using all of the above gas-phase attribution methods. The results are to be compared with zero-out difference out of those sectors in the host model runs. In addition, ozone contribution wil

  5. Distribution ozone concentration in Klang Valley using GIS approaches

    Science.gov (United States)

    Sulaiman, A.; Rahman, A. A. Ab; Maulud, K. N. Abdul; Latif, M. T.; Ahmad, F.; Wahid, M. A. Abdul; Ibrahim, M. A.; Halim, N. D. Abdul

    2017-05-01

    Today, ozone has become one of the main air pollutants in Malaysia. The high ozone precursor concentrations have been encouraging the ozone production. The development of the Klang Valley, Malaysia has many types of physical activities such as urban commercial, industrial area, settlement area and others, which has increased the risk of atmospheric pollution. The purpose of this paper is to determine the spatial distribution between types of land use and ozone concentration that are occurred in the year 2014. The study areas for this paper include Shah Alam, Kajang, Petaling Jaya and Port Klang. Distribution of ozone concentration will be showed via spatial analysis tools in Geographic Information Systems (GIS) approached and the types of land use will be extracted using Remote Sensing technique. The result showed 97 ppb (parts-per-billion, 10-9) and 161 ppb recorded at Port Klang and Shah Alam respectively that are mainly represented by the settlement area. Therefore, the physical land use need to be monitor and controlled by the government in order to make sure the ozone production for daily per hour will not exceed the regulation allowed.

  6. Distribution ozone concentration in Klang Valley using GIS approaches

    International Nuclear Information System (INIS)

    Sulaiman, A; Ab Rahman, A A; Abdul Maulud, K N; Abdul Wahid, M A; Ibrahim, M A; Latif, M T; Abdul Halim, N D; Ahmad, F

    2017-01-01

    Today, ozone has become one of the main air pollutants in Malaysia. The high ozone precursor concentrations have been encouraging the ozone production. The development of the Klang Valley, Malaysia has many types of physical activities such as urban commercial, industrial area, settlement area and others, which has increased the risk of atmospheric pollution. The purpose of this paper is to determine the spatial distribution between types of land use and ozone concentration that are occurred in the year 2014. The study areas for this paper include Shah Alam, Kajang, Petaling Jaya and Port Klang. Distribution of ozone concentration will be showed via spatial analysis tools in Geographic Information Systems (GIS) approached and the types of land use will be extracted using Remote Sensing technique. The result showed 97 ppb (parts-per-billion, 10 -9 ) and 161 ppb recorded at Port Klang and Shah Alam respectively that are mainly represented by the settlement area. Therefore, the physical land use need to be monitor and controlled by the government in order to make sure the ozone production for daily per hour will not exceed the regulation allowed. (paper)

  7. Radiative forcing and climate metrics for ozone precursor emissions: the impact of multi-model averaging

    Directory of Open Access Journals (Sweden)

    C. R. MacIntosh

    2015-04-01

    Full Text Available Multi-model ensembles are frequently used to assess understanding of the response of ozone and methane lifetime to changes in emissions of ozone precursors such as NOx, VOCs (volatile organic compounds and CO. When these ozone changes are used to calculate radiative forcing (RF (and climate metrics such as the global warming potential (GWP and global temperature-change potential (GTP there is a methodological choice, determined partly by the available computing resources, as to whether the mean ozone (and methane concentration changes are input to the radiation code, or whether each model's ozone and methane changes are used as input, with the average RF computed from the individual model RFs. We use data from the Task Force on Hemispheric Transport of Air Pollution source–receptor global chemical transport model ensemble to assess the impact of this choice for emission changes in four regions (East Asia, Europe, North America and South Asia. We conclude that using the multi-model mean ozone and methane responses is accurate for calculating the mean RF, with differences up to 0.6% for CO, 0.7% for VOCs and 2% for NOx. Differences of up to 60% for NOx 7% for VOCs and 3% for CO are introduced into the 20 year GWP. The differences for the 20 year GTP are smaller than for the GWP for NOx, and similar for the other species. However, estimates of the standard deviation calculated from the ensemble-mean input fields (where the standard deviation at each point on the model grid is added to or subtracted from the mean field are almost always substantially larger in RF, GWP and GTP metrics than the true standard deviation, and can be larger than the model range for short-lived ozone RF, and for the 20 and 100 year GWP and 100 year GTP. The order of averaging has most impact on the metrics for NOx, as the net values for these quantities is the residual of the sum of terms of opposing signs. For example, the standard deviation for the 20 year GWP is 2–3

  8. Meteorologically-adjusted trend analysis of surface observed ozone at three monitoring sites in Delhi, India: 2007-2011

    Science.gov (United States)

    Biswas, J.; Farooqui, Z.; Guttikunda, S. K.

    2012-12-01

    It is well known that meteorological parameters have significant impact on surface ozone concentrations. Therefore it is important to remove the effects of meteorology on ozone concentrations to correctly estimate long-term trends in ozone levels due to the alterations in precursor emissions. This is important for the development of effectual control strategies. In this study surface observed ozone trends in New Delhi are analyzed using Komogorov-Zurbenko (KZ) filter, US EPA ozone adjustment due to weather approach and the classification and regression tree method. The statistical models are applied to the ozone data at three observational sites in New Delhi metropolitan areas, 1) Income Tax Office (ITO) 2) Sirifort and 3) Delhi College of Engineering (DCE). The ITO site is located adjacent to a traffic crossing, Sirifort is an urban site and the DCE site is located in a residential area. The ITO site is also influenced by local industrial emissions. DCE has higher ozone levels than the other two sites. It was found that ITO has lowest ozone concentrations amongst the three sites due to ozone titrating due to industrial and on-road mobile NOx emissions. The statistical methods employed can assess ozone trends at these sites with a high degree of confidence and the results can be used to gauge the effectiveness of control strategies on surface ozone levels in New Delhi.

  9. Air pollution by ozone in Europe in summer 2003 - Overview of exceedances of EC ozone threshold values during the summer season April-August 2003 and comparisons with previous years

    Energy Technology Data Exchange (ETDEWEB)

    Fiala, J.; Cernikovsky, L.; Leeuw, F. de; Kurfuerst, P.; Aalst, R. van (eds.)

    2003-07-01

    In the period 1995-2003 of reporting tinder the old ozone directive, there has been little or no change in the reported exceedances of ozone threshold values. This is not unexpected as reductions in the EU emissions of nitrogen oxides and nonmethane volatile organic compounds, the main ozone precursors, have so far been limited - about 30 % between 1990 and 2000. 2010 under the national emission teilings directive. While peak ozone concentrations seem to go down, ozone concentration statistics relevant to the target values set in the new ozone directive show little or no reduction in the period 1996-2000. Very few stations actually show a significant downward trend for these stabstics. The threshold for warning the population continues to be exceeded on a few occasions Bach year, while the threshold for informing the population is exceeded at riost stations in most countries (outside northern Europe and Ireland) each year, generally more so in warm summers. These exceedances are likely to retur in years with temperatures above the long-term average until there is a substantially larger decrease in precursor emissions. A further reduction of about 30 % is foreseen towards Under current legislation and with the rate of turnover of the vehicle fleet, furtber reductions will gradually occur towards 2010, and further reductions may be necessary to achieve the target values of the new ozone directive. Note that, due to the uncertainties caused by year-to-year meteorological variations and the changes in the monitoring station configuration, these conclusions are tentative. (au)

  10. Regional trend analysis of surface ozone observations from monitoring networks in eastern North America, Europe and East Asia

    Science.gov (United States)

    Chang, K. L.; Petropavlovskikh, I. V.; Cooper, O. R.; Schultz, M.; Wang, T.

    2017-12-01

    Surface ozone is a greenhouse gas and pollutant detrimental to human health and crop and ecosystem productivity. The Tropospheric Ozone Assessment Report (TOAR) is designed to provide the research community with an up-to-date observation-based overview of tropospheric ozone's global distribution and trends. The TOAR Surface Ozone Database contains ozone metrics at thousands of monitoring sites around the world, densely clustered across mid-latitude North America, western Europe and East Asia. Calculating regional ozone trends across these locations is challenging due to the uneven spacing of the monitoring sites across urban and rural areas. To meet this challenge we conducted a spatial and temporal trend analysis of several TOAR ozone metrics across these three regions for summertime (April-September) 2000-2014, using the generalized additive mixed model (GAMM). Our analysis indicates that East Asia has the greatest human and plant exposure to ozone pollution among investigating regions, with increasing ozone levels through 2014. The results also show that ozone mixing ratios continue to decline significantly over eastern North America and Europe, however, there is less evidence for decreases of daytime average ozone at urban sites. The present-day spatial coverage of ozone monitors in East Asia (South Korea and Japan) and eastern North America is adequate for estimating regional trends by simply taking the average of the individual trends at each site. However the European network is more sparsely populated across its northern and eastern regions and therefore a simple average of the individual trends at each site does not yield an accurate regional trend. This analysis demonstrates that the GAMM technique can be used to assess the regional representativeness of existing monitoring networks, indicating those networks for which a regional trend can be obtained by simply averaging the trends of all individual sites and those networks that require a more

  11. Ozone and hydrogen peroxide applications for disinfection by-products control in drinking water

    International Nuclear Information System (INIS)

    Collivignarelli, C.; Sorlini, S.; Riganti, V.

    2001-01-01

    A great interest has been developed during the last years for ozone in drinking water treatments thanks to its strong oxidant and disinfectant power and for its efficiency in disinfection by-products (DBPs) precursors removal. However ozonization produces some specific DBPs, such as aldehydes and ketones; moreover, the presence of bromide in raw water engages ozone in a complex cycle in which both organic bromide and inorganic bromate are end products. In this paper the combination of hydrogen peroxide with ozone (known as peroxone process) and the ozone alone process were experimented on one surface water coming from the lake of Brugneto (Genova) in order to investigate bromate formation and trihalomethanes precursors removal during the oxidation process. The results show that the advanced peroxone process can be applied for bromate reduction (about 30-40%) with better results in comparison with the ozone alone process, while no advantages are shown for THMs precursors removal. The addition of in-line filtration step after pre-oxidation improves both bromate and THMs precursors removal, particularly with increasing hydrogen peroxide/ozone ratio in the oxidation step [it

  12. Ground-level ozone in four Chinese cities: precursors, regional transport and heterogeneous processes

    Science.gov (United States)

    Xue, L. K.; Wang, T.; Gao, J.; Ding, A. J.; Zhou, X. H.; Blake, D. R.; Wang, X. F.; Saunders, S. M.; Fan, S. J.; Zuo, H. C.; Zhang, Q. Z.; Wang, W. X.

    2014-12-01

    We analyzed the measurements of ozone (O3) and its precursors made at rural/suburban sites downwind of four large Chinese cities - Beijing, Shanghai, Guangzhou and Lanzhou, to elucidate their pollution characteristics, regional transport, in situ production, and impacts of heterogeneous processes. The same measurement techniques and observation-based model were used to minimize uncertainties in comparison of the results due to difference in methodologies. All four cities suffered from serious O3 pollution but showed different precursor distributions. The model-calculated in situ O3 production rates were compared with the observed change rates to infer the relative contributions of on-site photochemistry and transport. At the rural site downwind of Beijing, export of the well-processed urban plumes contributed to the extremely high O3 levels (up to an hourly value of 286 ppbv), while the O3 pollution observed at suburban sites of Shanghai, Guangzhou and Lanzhou was dominated by intense in situ production. The O3 production was in a volatile organic compound (VOC)-limited regime in both Shanghai and Guangzhou, and a NOx-limited regime in Lanzhou. The key VOC precursors are aromatics and alkenes in Shanghai, and aromatics in Guangzhou. The potential impacts on O3 production of several heterogeneous processes, namely, hydrolysis of dinitrogen pentoxide (N2O5), uptake of hydro peroxy radical (HO2) on particles and surface reactions of NO2 forming nitrous acid (HONO), were assessed. The analyses indicate the varying and considerable impacts of these processes in different areas of China depending on the atmospheric abundances of aerosol and NOx, and suggest the urgent need to better understand these processes and represent them in photochemical models.

  13. Global tropospheric ozone modeling: Quantifying errors due to grid resolution

    Science.gov (United States)

    Wild, Oliver; Prather, Michael J.

    2006-06-01

    Ozone production in global chemical models is dependent on model resolution because ozone chemistry is inherently nonlinear, the timescales for chemical production are short, and precursors are artificially distributed over the spatial scale of the model grid. In this study we examine the sensitivity of ozone, its precursors, and its production to resolution by running a global chemical transport model at four different resolutions between T21 (5.6° × 5.6°) and T106 (1.1° × 1.1°) and by quantifying the errors in regional and global budgets. The sensitivity to vertical mixing through the parameterization of boundary layer turbulence is also examined. We find less ozone production in the boundary layer at higher resolution, consistent with slower chemical production in polluted emission regions and greater export of precursors. Agreement with ozonesonde and aircraft measurements made during the NASA TRACE-P campaign over the western Pacific in spring 2001 is consistently better at higher resolution. We demonstrate that the numerical errors in transport processes on a given resolution converge geometrically for a tracer at successively higher resolutions. The convergence in ozone production on progressing from T21 to T42, T63, and T106 resolution is likewise monotonic but indicates that there are still large errors at 120 km scales, suggesting that T106 resolution is too coarse to resolve regional ozone production. Diagnosing the ozone production and precursor transport that follow a short pulse of emissions over east Asia in springtime allows us to quantify the impacts of resolution on both regional and global ozone. Production close to continental emission regions is overestimated by 27% at T21 resolution, by 13% at T42 resolution, and by 5% at T106 resolution. However, subsequent ozone production in the free troposphere is not greatly affected. We find that the export of short-lived precursors such as NOx by convection is overestimated at coarse resolution.

  14. Effect of Climate Change on Surface Ozone over North America, Europe, and East Asia

    Science.gov (United States)

    Schnell, Jordan L.; Prather, Michael J.; Josse, Beatrice; Naik, Vaishali; Horowitz, Larry W.; Zeng, Guang; Shindell, Drew T.; Faluvegi, Greg

    2016-01-01

    The effect of future climate change on surface ozone over North America, Europe, and East Asia is evaluated using present-day (2000s) and future (2100s) hourly surface ozone simulated by four global models. Future climate follows RCP8.5, while methane and anthropogenic ozone precursors are fixed at year-2000 levels. Climate change shifts the seasonal surface ozone peak to earlier in the year and increases the amplitude of the annual cycle. Increases in mean summertime and high-percentile ozone are generally found in polluted environments, while decreases are found in clean environments. We propose climate change augments the efficiency of precursor emissions to generate surface ozone in polluted regions, thus reducing precursor export to neighboring downwind locations. Even with constant biogenic emissions, climate change causes the largest ozone increases at high percentiles. In most cases, air quality extreme episodes become larger and contain higher ozone levels relative to the rest of the distribution.

  15. The Ozone Monitoring Instrument: overview of 14 years in space

    Science.gov (United States)

    Levelt, Pieternel F.; Joiner, Joanna; Tamminen, Johanna; Pepijn Veefkind, J.; Bhartia, Pawan K.; Stein Zweers, Deborah C.; Duncan, Bryan N.; Streets, David G.; Eskes, Henk; van der A, Ronald; McLinden, Chris; Fioletov, Vitali; Carn, Simon; de Laat, Jos; DeLand, Matthew; Marchenko, Sergey; McPeters, Richard; Ziemke, Jerald; Fu, Dejian; Liu, Xiong; Pickering, Kenneth; Apituley, Arnoud; González Abad, Gonzalo; Arola, Antti; Boersma, Folkert; Miller, Christopher Chan; Chance, Kelly; de Graaf, Martin; Hakkarainen, Janne; Hassinen, Seppo; Ialongo, Iolanda; Kleipool, Quintus; Krotkov, Nickolay; Li, Can; Lamsal, Lok; Newman, Paul; Nowlan, Caroline; Suleiman, Raid; Gijsbert Tilstra, Lieuwe; Torres, Omar; Wang, Huiqun; Wargan, Krzysztof

    2018-04-01

    This overview paper highlights the successes of the Ozone Monitoring Instrument (OMI) on board the Aura satellite spanning a period of nearly 14 years. Data from OMI has been used in a wide range of applications and research resulting in many new findings. Due to its unprecedented spatial resolution, in combination with daily global coverage, OMI plays a unique role in measuring trace gases important for the ozone layer, air quality, and climate change. With the operational very fast delivery (VFD; direct readout) and near real-time (NRT) availability of the data, OMI also plays an important role in the development of operational services in the atmospheric chemistry domain.

  16. Global tropospheric ozone modeling: Quantifying errors due to grid resolution

    OpenAIRE

    Wild, Oliver; Prather, Michael J

    2006-01-01

    Ozone production in global chemical models is dependent on model resolution because ozone chemistry is inherently nonlinear, the timescales for chemical production are short, and precursors are artificially distributed over the spatial scale of the model grid. In this study we examine the sensitivity of ozone, its precursors, and its production to resolution by running a global chemical transport model at four different resolutions between T21 (5.6° × 5.6°) and T106 (1.1° × 1.1°) and by quant...

  17. Estimating contribution of wildland fires to ambient ozone levels in National Parks in the Sierra Nevada, California

    International Nuclear Information System (INIS)

    Preisler, Haiganoush K.; Zhong Shiyuan; Esperanza, Annie; Brown, Timothy J.; Bytnerowicz, Andrzej; Tarnay, Leland

    2010-01-01

    Data from four continuous ozone and weather monitoring sites operated by the National Park Service in Sierra Nevada, California, are used to develop an ozone forecasting model and to estimate the contribution of wildland fires on ambient ozone levels. The analyses of weather and ozone data pointed to the transport of ozone precursors from the Central Valley as an important source of pollution in these National Parks. Comparisons of forecasted and observed values demonstrated that accurate forecasts of next-day hourly ozone levels may be achieved by using a time series model with historic averages, expected local weather and modeled PM values as explanatory variables. Results on fire smoke influence indicated occurrence of significant increases in average ozone levels with increasing fire activity. The overall effect on diurnal ozone values, however, was small when compared with the amount of variability attributed to sources other than fire. - We have demonstrated that it is possible to produce accurate forecasts of next-day hourly ozone levels in the Sierra Nevada, CA, during fire season.

  18. Estimating contribution of wildland fires to ambient ozone levels in National Parks in the Sierra Nevada, California

    Energy Technology Data Exchange (ETDEWEB)

    Preisler, Haiganoush K., E-mail: hpreisler@fs.fed.u [USDA Forest Service, Pacific Southwest Research Station, 800 Buchanan St, Albany, CA 94710 (United States); Zhong Shiyuan, E-mail: zhongs@msu.ed [Department of Geography, Michigan State University, 116 Geography Building, East Lansing, MI 48824-1117 (United States); Esperanza, Annie, E-mail: annie_esperanza@nps.go [Sequoia and Kings Canyon National Parks, 47050 Generals Highway Three Rivers, CA 93271 (United States); Brown, Timothy J., E-mail: tim.brown@dri.ed [Desert Research Institute, 2215 Raggio Parkway, Reno, NV 89521-10095 (United States); Bytnerowicz, Andrzej, E-mail: abytnerowicz@fs.fed.u [USDA Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Drive, Riverside, CA 92507 (United States); Tarnay, Leland, E-mail: Leland_Tarnay@nps.go [Yosemite National Park, El Portal, CA 95318 (United States)

    2010-03-15

    Data from four continuous ozone and weather monitoring sites operated by the National Park Service in Sierra Nevada, California, are used to develop an ozone forecasting model and to estimate the contribution of wildland fires on ambient ozone levels. The analyses of weather and ozone data pointed to the transport of ozone precursors from the Central Valley as an important source of pollution in these National Parks. Comparisons of forecasted and observed values demonstrated that accurate forecasts of next-day hourly ozone levels may be achieved by using a time series model with historic averages, expected local weather and modeled PM values as explanatory variables. Results on fire smoke influence indicated occurrence of significant increases in average ozone levels with increasing fire activity. The overall effect on diurnal ozone values, however, was small when compared with the amount of variability attributed to sources other than fire. - We have demonstrated that it is possible to produce accurate forecasts of next-day hourly ozone levels in the Sierra Nevada, CA, during fire season.

  19. Rapid increases in tropospheric ozone production and export from China

    NARCIS (Netherlands)

    Verstraeten, W.W.; Neu, J.L.; Williams, J.E.; Bowman, K.W.; Worden, J.R.; Boersma, K.F.

    2015-01-01

    Rapid population growth and industrialization have driven substantial increases in Asian ozone precursor emissions over the past decade1, with highly uncertain impacts on regional and global tropospheric ozone levels. According to ozonesonde measurements2, 3, tropospheric ozone concentrations at two

  20. Ozone Transport Aloft Drives Surface Ozone Maxima Across the Mojave Desert

    Science.gov (United States)

    VanCuren, R. A.

    2014-12-01

    A persistent layer of polluted air in the lower free troposphere over the Mojave Desert (California and Nevada) drives spring and summer surface ozone maxima as deep afternoon mixing delivers ozone and ozone precursors to surface measurement sites 200 km or more downwind of the mountains that separate the deserts from the heavily populated coastal areas of California. Pollutants in this elevated layer derive from California source regions (the Los Angeles megacity region and the intensive agricultural region of the San Joaquin Valley), and from long-range transport from Asia. Recognition of this poorly studied persistent layer explains and expands the significance of previously published reports of ozone and other pollutants observed in and over the Mojave Desert, resolves an apparent paradox in the timing of ozone peaks due to transport from the upwind basins, and provides a new perspective on the long-range downwind impacts of megacity pollution plumes.

  1. 50 years of monitoring of the ozone layer in the Czech Republic - results and challenges

    Science.gov (United States)

    Vanicek, Karel; Skrivankova, Pavla; Metelka, Ladislav; Stanek, Martin

    2010-05-01

    Long-term observations of total ozone (TOZ) and vertical ozone profiles, the basic parameters of the ozone layer, have been performed at the Solar and Ozone Observatory (SOO) Hradec Kralove and at the Aerological Department (AD) Praha of the Czech Hydrometeorological Institute (CHMI) since 1961 and 1992 respectively. The Dobson and Brewer spectrophotometers regularly calibrated towards the international references and electro-chemical ECC ozone sondes are used for the measurements. The observations contribute to the global GAW and NDACC ozone monitoring systems. Up to now analyses of the data give the basic findings given bellow and documented in the presentation. Some of them have important implication to the international ozone monitoring infrastructure, as well. - The decrease of TOZ by about 5-7 % in the winter-spring months towards the pre ozone-hole period have occurred since the mid eighties. This is in good agreement by the magnitude and time with depletion of the ozone layer due to chemical destruction of ozone in the NH mid-latitudes. - Significant depletion 3-5 % of TOZ has been identified also in the summer season since the early nineties. As this can not be attributed to the man-made chemical processes a change in the UT/LS dynamics over Central Europe is the most probable reason. - Aerological measurements taken at AD show that the summer reduction of TOZ very well coincides with a change of UT/LS temperature that persists for about two decades over the Czech territory. Therefore it has a long-term character that can be regarded as a climate shift in UT/LS and need to be further investigated. - 15 years of unique simultaneous Dobson/Brewer observations of TOZ performed at SOO show systematic seasonal deviations between both data sets that exceed instrumental accuracy of measurements. The differences are mostly caused by different wavelengths and their ozone absorption coefficients used by both instruments. As the Brewer observations are being

  2. The Ozone Monitoring Instrument: overview of 14 years in space

    Directory of Open Access Journals (Sweden)

    P. F. Levelt

    2018-04-01

    Full Text Available This overview paper highlights the successes of the Ozone Monitoring Instrument (OMI on board the Aura satellite spanning a period of nearly 14 years. Data from OMI has been used in a wide range of applications and research resulting in many new findings. Due to its unprecedented spatial resolution, in combination with daily global coverage, OMI plays a unique role in measuring trace gases important for the ozone layer, air quality, and climate change. With the operational very fast delivery (VFD; direct readout and near real-time (NRT availability of the data, OMI also plays an important role in the development of operational services in the atmospheric chemistry domain.

  3. PHOTOCHEMICAL AIR POLLUTION IN THE NORTH OF PORTUGAL: A HIGH TROPOSHERIC OZONE EPISODE

    Science.gov (United States)

    Monteiro, A.; Carvalho, A.; Tchepel, O.; Ferreira, J.; Martins, H.; Miranda, A.; Borrego, C.; Saavedra, S.; Rodríguez, A.; Souto, J. A.

    2009-12-01

    Very high concentrations of ozone are continuously measured at the monitoring station at Lamas d’Olo, located at the North of Portugal,. A particular high photochemical episode occurred between 11 and 13 of July 2005, registering ozone hourly maximum values above 350 µg.m-3. This ozone-rich episode is investigated in this paper, in order to identify its origin and formation. Besides the analysis of both meteorological and air quality monitoring datasets, a numerical modelling approach, based on MM5-CAMx system, was used to simulate the dispersion and transport (horizontal and vertical) of the photochemical pollutants and its precursors. A cross spectrum analysis of the meteorological and air quality time series was performed, in the frequency domain, to establish the relationships between ozone data measured at Lamas d’Olo with air quality data from neighbourhood stations and meteorological parameters. Results point out different behaviour/contribution between the analysed sites. Moreover, different contributions of the u and v wind component on the ozone concentration fluctuations were found suggesting the presence a mountain breeze circulation and a north synoptic transport. The preliminary modelling results pointed out that the vertical transport of pollutants are responsible for the measured high concentrations, combined with particular meteorological conditions, related to the planetary boundary layer (PBL) development. The pollutants transported and existent at high vertical levels are captured/trapped when the PBL height reaches its daily maximum, and extremely high ozone ground level concentrations are consequently measured.

  4. Tropospheric ozone using an emission tagging technique in the CAM-Chem and WRF-Chem models

    Science.gov (United States)

    Lupascu, A.; Coates, J.; Zhu, S.; Butler, T. M.

    2017-12-01

    Tropospheric ozone is a short-lived climate forcing pollutant. High concentration of ozone can affect human health (cardiorespiratory and increased mortality due to long-term exposure), and also it damages crops. Attributing ozone concentrations to the contributions from different sources would indicate the effects of locally emitted or transported precursors on ozone levels in specific regions. This information could be used as an important component of the design of emissions reduction strategies by indicating which emission sources could be targeted for effective reductions, thus reducing the burden of ozone pollution. Using a "tagging" approach within the CAM-Chem (global) and WRF-Chem (regional) models, we can quantify the contribution of individual emission of NOx and VOC precursors on air quality. Hence, when precursor emissions of NOx are tagged, we have seen that the largest contributors on ozone levels are the anthropogenic sources, while in the case of precursor emissions of VOCs, the biogenic sources and methane account for more than 50% of ozone levels. Further, we have extended the NOx tagging method in order to investigate continental source region contributions to concentrations of ozone over various receptor regions over the globe, with a zoom over Europe. In general, summertime maximum ozone in most receptor regions is largely attributable to local emissions of anthropogenic NOx and biogenic VOC. During the rest of the year, especially during springtime, ozone in most receptor regions shows stronger influences from anthropogenic emissions of NOx and VOC in remote source regions.

  5. Ozone therapy in periodontics.

    Science.gov (United States)

    Gupta, G; Mansi, B

    2012-02-22

    Gingival and Periodontal diseases represent a major concern both in dentistry and medicine. The majority of the contributing factors and causes in the etiology of these diseases are reduced or treated with ozone in all its application forms (gas, water, oil). The beneficial biological effects of ozone, its anti-microbial activity, oxidation of bio-molecules precursors and microbial toxins implicated in periodontal diseases and its healing and tissue regeneration properties, make the use of ozone well indicated in all stages of gingival and periodontal diseases. The primary objective of this article is to provide a general review about the clinical applications of ozone in periodontics. The secondary objective is to summarize the available in vitro and in vivo studies in Periodontics in which ozone has been used. This objective would be of importance to future researchers in terms of what has been tried and what the potentials are for the clinical application of ozone in Periodontics.

  6. Photochemistry and transport of tropospheric ozone and its precursors in urban and remote environments

    Science.gov (United States)

    Anderson, Daniel Craig

    Tropospheric ozone (O3) adversely affects human health, reduces crop yields, and contributes to climate forcing. To limit these effects, the processes controlling O3 abundance as well as that of its precursor molecules must be fully characterized. Here, I examine three facets of O 3 production, both in heavily polluted and remote environments. First, using in situ observations from the DISCOVER-AQ field campaign in the Baltimore/Washington region, I evaluate the emissions of the O 3 precursors CO and NOx (NOx = NO + NO2) in the National Emissions Inventory (NEI). I find that CO/NOx emissions ratios derived from observations are 21% higher than those predicted by the NEI. Comparisons to output from the CMAQ model suggest that CO in the NEI is accurate within 15 +/- 11%, while NOx emissions are overestimated by 51-70%, likely due to errors in mobile sources. These results imply that ambient ozone concentrations will respond more efficiently to NOx controls than current models suggest. I then investigate the source of high O3 and low H2O structures in the Tropical Western Pacific (TWP). A combination of in situ observations, satellite data, and models show that the high O3 results from photochemical production in biomass burning plumes from fires in tropical Southeast Asia and Central Africa; the low relative humidity results from large-scale descent in the tropics. Because these structures have frequently been attributed to mid-latitude pollution, biomass burning in the tropics likely contributes more to the radiative forcing of climate than previously believed. Finally, I evaluate the processes controlling formaldehyde (HCHO) in the TWP. Convective transport of near surface HCHO leads to a 33% increase in upper tropospheric HCHO mixing ratios; convection also likely increases upper tropospheric CH 3OOH to ~230 pptv, enough to maintain background HCHO at ~75 pptv. The long-range transport of polluted air, with NO four times the convectively controlled background

  7. Ozone Production in Global Tropospheric Models: Quantifying Errors due to Grid Resolution

    Science.gov (United States)

    Wild, O.; Prather, M. J.

    2005-12-01

    Ozone production in global chemical models is dependent on model resolution because ozone chemistry is inherently nonlinear, the timescales for chemical production are short, and precursors are artificially distributed over the spatial scale of the model grid. In this study we examine the sensitivity of ozone, its precursors, and its production to resolution by running a global chemical transport model at four different resolutions between T21 (5.6° × 5.6°) and T106 (1.1° × 1.1°) and by quantifying the errors in regional and global budgets. The sensitivity to vertical mixing through the parameterization of boundary layer turbulence is also examined. We find less ozone production in the boundary layer at higher resolution, consistent with slower chemical production in polluted emission regions and greater export of precursors. Agreement with ozonesonde and aircraft measurements made during the NASA TRACE-P campaign over the Western Pacific in spring 2001 is consistently better at higher resolution. We demonstrate that the numerical errors in transport processes at a given resolution converge geometrically for a tracer at successively higher resolutions. The convergence in ozone production on progressing from T21 to T42, T63 and T106 resolution is likewise monotonic but still indicates large errors at 120~km scales, suggesting that T106 resolution is still too coarse to resolve regional ozone production. Diagnosing the ozone production and precursor transport that follow a short pulse of emissions over East Asia in springtime allows us to quantify the impacts of resolution on both regional and global ozone. Production close to continental emission regions is overestimated by 27% at T21 resolution, by 13% at T42 resolution, and by 5% at T106 resolution, but subsequent ozone production in the free troposphere is less significantly affected.

  8. Measurement of Ozone Production Sensor

    Directory of Open Access Journals (Sweden)

    M. Cazorla

    2010-05-01

    Full Text Available A new ambient air monitor, the Measurement of Ozone Production Sensor (MOPS, measures directly the rate of ozone production in the atmosphere. The sensor consists of two 11.3 L environmental chambers made of UV-transmitting Teflon film, a unit to convert NO2 to O3, and a modified ozone monitor. In the sample chamber, flowing ambient air is exposed to the sunlight so that ozone is produced just as it is in the atmosphere. In the second chamber, called the reference chamber, a UV-blocking film over the Teflon film prevents ozone formation but allows other processes to occur as they do in the sample chamber. The air flows that exit the two chambers are sampled by an ozone monitor operating in differential mode so that the difference between the two ozone signals, divided by the exposure time in the chambers, gives the ozone production rate. High-efficiency conversion of NO2 to O3 prior to detection in the ozone monitor accounts for differences in the NOx photostationary state that can occur in the two chambers. The MOPS measures the ozone production rate, but with the addition of NO to the sampled air flow, the MOPS can be used to study the sensitivity of ozone production to NO. Preliminary studies with the MOPS on the campus of the Pennsylvania State University show the potential of this new technique.

  9. Reconciliation of Halogen-Induced Ozone Loss with the Total-Column Ozone Record

    Science.gov (United States)

    Shepherd, T. G.; Plummer, D. A.; Scinocca, J. F.; Hegglin, M. I.; Fioletov, V. E.; Reader, M. C.; Remsberg, E.; von Clarmann, T.; Wang, H. J.

    2014-01-01

    The observed depletion of the ozone layer from the 1980s onwards is attributed to halogen source gases emitted by human activities. However, the precision of this attribution is complicated by year-to-year variations in meteorology, that is, dynamical variability, and by changes in tropospheric ozone concentrations. As such, key aspects of the total-column ozone record, which combines changes in both tropospheric and stratospheric ozone, remain unexplained, such as the apparent absence of a decline in total-column ozone levels before 1980, and of any long-term decline in total-column ozone levels in the tropics. Here we use a chemistry-climate model to estimate changes in halogen-induced ozone loss between 1960 and 2010; the model is constrained by observed meteorology to remove the eects of dynamical variability, and driven by emissions of tropospheric ozone precursors to separate out changes in tropospheric ozone. We show that halogen-induced ozone loss closely followed stratospheric halogen loading over the studied period. Pronounced enhancements in ozone loss were apparent in both hemispheres following the volcanic eruptions of El Chichon and, in particular, Mount Pinatubo, which significantly enhanced stratospheric aerosol loads. We further show that approximately 40% of the long-term non-volcanic ozone loss occurred before 1980, and that long-term ozone loss also occurred in the tropical stratosphere. Finally, we show that halogeninduced ozone loss has declined by over 10% since stratospheric halogen loading peaked in the late 1990s, indicating that the recovery of the ozone layer is well underway.

  10. Video-documentation: 'The Pannonic ozon project'

    International Nuclear Information System (INIS)

    Loibl, W.; Cabela, E.; Mayer, H. F.; Schmidt, M.

    1998-07-01

    Goal of the project was the production of a video film as documentation of the Pannonian Ozone Project- POP. The main part of the video describes the POP-model consisting of the modules meteorology, emissions and chemistry, developed during the POP-project. The model considers the European emission patterns of ozone precursors and the actual wind fields. It calculates ozone build up and depletion within air parcels due to emission and weather situation along trajectory routes. Actual ozone concentrations are calculated during model runs simulating the photochemical processes within air parcels moving along 4 day trajectories before reaching the Vienna region. The model computations were validated during extensive ground and aircraft-based measurements of ozone precursors and ozone concentration within the POP study area. Scenario computations were used to determine how much ozone can be reduced in north-eastern Austria by emissions control measures. The video lasts 12:20 minutes and consists of computer animations and life video scenes, presenting the ozone problem in general, the POP model and the model results. The video was produced in co-operation by the Austrian Research Center Seibersdorf - Department of Environmental Planning (ARCS) and Joanneum Research - Institute of Informationsystems (JR). ARCS was responsible for idea, concept, storyboard and text while JR was responsible for computer animation and general video production. The speaker text was written with scientific advice by the POP - project partners: Institute of Meteorology and Physics, University of Agricultural Sciences- Vienna, Environment Agency Austria - Air Quality Department, Austrian Research Center Seibersdorf- Environmental Planning Department/System Research Division. The film was produced as German and English version. (author)

  11. Investigating a high ozone episode in a rural mountain site

    International Nuclear Information System (INIS)

    Monteiro, A.; Strunk, A.; Carvalho, A.; Tchepel, O.; Miranda, A.I.; Borrego, C.; Saavedra, S.; Rodríguez, A.; Souto, J.; Casares, J.; Friese, E.; Elbern, H.

    2012-01-01

    A very high ozone episode with observed hourly values above 350 μg m −3 occurred in July 2005 at the Lamas d’Olo air quality monitoring station, located in a mountainous area in the north of Portugal. Aiming to identify the origin and formation of this ozone-rich episode, a statistical analysis and a modelling approach were applied. A cross-spectrum analysis in the frequency domain and a synoptic analysis of the meteorological and air quality time series were performed. In order to go further in this analysis, a numerical modelling approach was applied. The results indicate that the transport of ozone and its precursors is the main responsible for the high ozone concentrations. Together with the local mountain breeze and subsidence conditions, the sea-breeze circulation transporting pollutants from the coastal urban and industrialized areas that reach the site during late afternoon turn out to be the driving forces for the ozone peaks. - Highlights: ► A very high ozone episode occurred in a rural mountain site of Portugal in 2004. ► Data cross-spectrum analysis in the frequency domain was performed. ► A numerical modelling approach was also applied. ► The sea-breeze circulation transported pollutants from the urban and industrialized coast. ► The mountain breeze and subsidence conditions were also driving forces for ozone peaks. - The sea-breeze transporting pollutants from the coast, the mountain breeze and subsidence conditions, were the driving forces for the ozone episode occurred in a rural mountain site.

  12. [Health impact of ozone in 13 Italian cities].

    Science.gov (United States)

    Mitis, Francesco; Iavarone, Ivano; Martuzzi, Marco

    2007-01-01

    to estimate the health impact of ozone in 13 Italian cities over 200,000 inhabitants and to produce basic elements to permit the reproducibility of the study in other urban locations. the following data have been used: population data (2001), health data (2001 or from scientific literature), environmental data (2002-2004), from urban background monitoring station and concentration/response risk coefficients derived from recent metanalyses. The indicators SOMO35 and SOMO0 have been used as a proxi of the average exposure to calcolate attributable deaths (and years of life lost) and several causes of morbility for ozone concentrations over 70 microg/m3. acute mortality for all causes and for cardiovascular mortality, respiratory-related hospital admissions in elderly, asthma exacerbation in children and adults, minor restricted activity days, lower respiratory symptoms in children. over 500 (1900) deaths, the 0.6% (2.1%) of total mortality, equivalent to about 6000 (22,000) years of life lost are attributable to ozone levels over 70 microg/m3 in the 13 Italian cities under study. Larger figures, in the order of thousands, are attributable to less severe morbidity outcomes. The health impact of ozone in Italian towns is relevant in terms of acute mortality and morbidity, although less severe than PM10 impact. Background ozone levels are increasing. Abatement strategies for ozone concentrations should consider the whole summer and not only "peak" days and look at policies limiting the concentration of precursors produced by traffic sources. Relevant health benefits can be obtained also under levels proposed as guidelines in the present environmental regulations.

  13. Ozone pollution and ozone biomonitoring in European cities Part II. Ozone-induced plant injury and its relationship with descriptors of ozone pollution

    DEFF Research Database (Denmark)

    Klumpp, A.; Ansel, W.; Klumpp, G.

    2006-01-01

    within local networks were relatively small, but seasonal and inter-annual differences were strong due to the variability of meteorological conditions and related ozone concentrations. The 2001 data revealed a significant relationship between foliar injury degree and various descriptors of ozone...... pollution such as mean value, AOT20 and AOT40. Examining individual sites of the local monitoring networks separately, however, yielded noticeable differences. Some sites showed no association between ozone pollution and ozone-induced effects, whereas others featured almost linear relationships...

  14. A cloud-ozone data product from Aura OMI and MLS satellite measurements

    Directory of Open Access Journals (Sweden)

    J. R. Ziemke

    2017-11-01

    Full Text Available Ozone within deep convective clouds is controlled by several factors involving photochemical reactions and transport. Gas-phase photochemical reactions and heterogeneous surface chemical reactions involving ice, water particles, and aerosols inside the clouds all contribute to the distribution and net production and loss of ozone. Ozone in clouds is also dependent on convective transport that carries low-troposphere/boundary-layer ozone and ozone precursors upward into the clouds. Characterizing ozone in thick clouds is an important step for quantifying relationships of ozone with tropospheric H2O, OH production, and cloud microphysics/transport properties. Although measuring ozone in deep convective clouds from either aircraft or balloon ozonesondes is largely impossible due to extreme meteorological conditions associated with these clouds, it is possible to estimate ozone in thick clouds using backscattered solar UV radiation measured by satellite instruments. Our study combines Aura Ozone Monitoring Instrument (OMI and Microwave Limb Sounder (MLS satellite measurements to generate a new research product of monthly-mean ozone concentrations in deep convective clouds between 30° S and 30° N for October 2004–April 2016. These measurements represent mean ozone concentration primarily in the upper levels of thick clouds and reveal key features of cloud ozone including: persistent low ozone concentrations in the tropical Pacific of  ∼ 10 ppbv or less; concentrations of up to 60 pphv or greater over landmass regions of South America, southern Africa, Australia, and India/east Asia; connections with tropical ENSO events; and intraseasonal/Madden–Julian oscillation variability. Analysis of OMI aerosol measurements suggests a cause and effect relation between boundary-layer pollution and elevated ozone inside thick clouds over landmass regions including southern Africa and India/east Asia.

  15. Aerosols and surface UV products form Ozone Monitoring Instrument observations: An overview

    NARCIS (Netherlands)

    Torres, O.; Tanskanen, A.; Veihelmann, B.; Ahn, C.; Braak, R.; Bhartia, P.K.; Veefkind, J.P.; Levelt, P.F.

    2007-01-01

    We present an overview of the theoretical and algorithmic aspects of the Ozone Monitoring Instrument (OMI) aerosol and surface UV algorithms. Aerosol properties are derived from two independent algorithms. The nearUV algorithm makes use of OMI observations in the 350-390 nm spectral region to

  16. Volatile organic compounds speciation and their influence on ozone formation potential in an industrialized urban area in Brazil.

    Science.gov (United States)

    Galvão, Elson Silva; Santos, Jane Meri; Reis Junior, Neyval Costa; Stuetz, Richard Michael

    2016-09-01

    Speciation and the influence on the ozone formation potential (OFP) from volatile organic compounds (VOCs) have been studied between February June 2013 in Vitória, ES, Brazil. Passive samplers were installed at three air-quality monitoring stations and a total of 96 samplings were collected. A total of 78 VOCs were characterized by gas chromatograph-mass spectrometer. The predominant group was organic acids, followed by alcohols and substituted aromatics and 14 precursor species were quantified. An analysis correlating concentrations with wind direction was conducted to identify possible sources. The OFP was calculated applying the scale of maximum incremental reactivity proposed by Carter.[ 23 ] Ozone precursors with the greatest OFP such as undecane, toluene, ethylbenzene and m, p-xylene compounds were the most abundant with means of 0.855, 0.365, 0.259 and 0.289 µg m(-3), respectively. The benzene, toluene, ethylbenzene and xylene (BTEX) group was found below the limits considered harmful to the health of the population living in Vitória. The OFP calculated for the precursors group was 22.55 µg m(-3) for the rainy season and 32.11 µg m(-3) for the dry season. The VOC/NOx ratio in Vitória is approximately 1.71, indicating that the region has a VOC-limiting condition for the production of ozone.

  17. Vitamin D Synthesis by UV Radiation: the Importance of Ozone Monitoring

    Science.gov (United States)

    Olds, W. J.; Moore, M. R.; Kimlin, M. G.

    2006-12-01

    The majority of humans rely on incidental sun exposure to maintain vitamin D sufficiency. Depending on where thresholds of vitamin D "sufficiency" are defined, it was recently stated that up to one billion people worldwide have suboptimal vitamin D levels (Bouillon, R., University of Leuven). Even in sunny southeast Queensland, the world's skin cancer capital, a 2006 study uncovered deficiency rates of up to 78% (at a threshold of 75 nmol/L of circulating 25-hydroxyvitamin D). Vitamin D regulates calcium absorption and inadequate levels are proven to result in osteomalacia, osteoporosis, rickets, bone pain and general skeletal weakness. Recent evidence also suggests vitamin D plays a preventative role in autoimmune diseases including numerous cancers, diabetes, schizophrenia, coronary heart disease, depression and other disorders. The most promising means of alleviating the worldwide burden of vitamin D deficiency seems to be by increased UV exposure. However, a much more mature understanding of UV exposures encountered in everyday life is required. This understanding is fundamentally founded in geophysics. UV exposures are strongly influenced by season/time of year, time of day, climate, location, pollution, aerosols and, importantly, ozone. In this work, we use computer simulations to obtain daily totals of vitamin D producing UV at numerous latitudes during one year. The ozone concentration is varied from 260 DU to 360 DU to determine the role of ozone variability on the ambient levels of vitamin D UV. Vitamin D synthesis is highly dependent on UVB. In our results, we demonstrate that this has important implications. Namely, vitamin D is strongly affected by ozone variability, since ozone filters UVB more strongly than UVA. Moreover, since erythema (sunburn) can occur at UVA wavelengths, ozone variation will more strongly affect vitamin D synthesis than erythema. Our results highlight that ozone monitoring is essential for understanding appropriate UV exposures

  18. Early Results from TROPOMI on the Copernicus Sentinel 5 Precursor

    Science.gov (United States)

    Veefkind, J. P.; Kleipool, Q.; Ludewig, A.; Stein-Zweers, D.; Aben, I.; De Vries, J.; Loyola, D. G.; Nett, H.; Richter, A.; Van Roozendael, M.; Siddans, R.; Wagner, T.; Dehn, A.; Zehner, C.; Levelt, P.

    2017-12-01

    The Copernicus Sentinel 5 Precursor (S5P) is the first of the European Sentinels satellites dedicated to monitoring of the atmospheric composition. S5P is planned for launch in the 3rd quarter of 2017. The mission objectives of S5P are to monitor air quality, climate and the ozone layer, in the time period between 2017 and 2023. S5P will fly in a Sun-synchronized polar orbit with a 13:30 hr local equator crossing time. The single payload of the S5P mission is TROPOspheric Monitoring Instrument (TROPOMI), which is developed by The Netherlands in cooperation with the European Space Agency (ESA). TROPOMI is a nadir viewing shortwave spectrometer that measures in the UV-visible wavelength range (267-499 nm), the near infrared (661-775 nm) and the shortwave infrared (2300-2389 nm). With a spatial resolution of better than 7x7 km2 at nadir and almost 20 million measurements per day, TROPOMI will be a major step forward compared to its predecessors OMI (Ozone Monitoring Instrument) and SCIAMACHY (Scanning Imaging Absorption Spectrometer for Atmospheric Chartography). The spatial resolution is combined with a wide swath to allow for daily global coverage. The TROPOMI/S5P geophysical (Level 2) operational data products include nitrogen dioxide, carbon monoxide, ozone (total column, tropospheric column & profile), methane, sulfur dioxide, formaldehyde and aerosol and cloud parameters. The S5P will fly in a so-called loose formation with the U.S. Suomi NPP (National Polar-orbiting Partnership) satellite. The primary objective for this formation flying is to use the cloud clearing capabilities of the VIIRS (Visible Infrared Imager Radiometer Suite). The temporal separation between TROPOMI and VIIRS will be less than 5 minutes. Once this formation has been established, it will enable synergistic data products and scientific research potentials.

  19. Ozone concentrations and damage for realistic future European climate and air quality scenarios

    Science.gov (United States)

    Hendriks, Carlijn; Forsell, Nicklas; Kiesewetter, Gregor; Schaap, Martijn; Schöpp, Wolfgang

    2016-11-01

    Ground level ozone poses a significant threat to human health from air pollution in the European Union. While anthropogenic emissions of precursor substances (NOx, NMVOC, CH4) are regulated by EU air quality legislation and will decrease further in the future, the emissions of biogenic NMVOC (mainly isoprene) may increase significantly in the coming decades if short-rotation coppice plantations are expanded strongly to meet the increased biofuel demand resulting from the EU decarbonisation targets. This study investigates the competing effects of anticipated trends in land use change, anthropogenic ozone precursor emissions and climate change on European ground level ozone concentrations and related health and environmental impacts until 2050. The work is based on a consistent set of energy consumption scenarios that underlie current EU climate and air quality policy proposals: a current legislation case, and an ambitious decarbonisation case. The Greenhouse Gas-Air Pollution Interactions and Synergies (GAINS) integrated assessment model was used to calculate air pollutant emissions for these scenarios, while land use change because of bioenergy demand was calculated by the Global Biosphere Model (GLOBIOM). These datasets were fed into the chemistry transport model LOTOS-EUROS to calculate the impact on ground level ozone concentrations. Health damage because of high ground level ozone concentrations is projected to decline significantly towards 2030 and 2050 under current climate conditions for both energy scenarios. Damage to plants is also expected to decrease but to a smaller extent. The projected change in anthropogenic ozone precursor emissions is found to have a larger impact on ozone damage than land use change. The increasing effect of a warming climate (+2-5 °C across Europe in summer) on ozone concentrations and associated health damage, however, might be higher than the reduction achieved by cutting back European ozone precursor emissions. Global

  20. [Ozone concentration distribution of urban].

    Science.gov (United States)

    Yin, Yong-quan; Li, Chang-mei; Ma, Gui-xia; Cui, Zhao-jie

    2004-11-01

    The increase of ozone concentration in urban is one of the most important research topics on environmental science. With the increase of nitrogen oxides and hydrogen-carbon compounds which are exhausted from cars, the ozone concentration in urban is obviously increased on sunlight, and threat of photochemistry smog will be possible. Therefore, it is very important to monitor and study the ozone concentration distribution in urban. The frequency-distribution, diurnal variation and monthly variation of ozone concentration were studied on the campus of Shandong University during six months monitoring. The influence of solar radiation and weather conditions on ozone concentration were discussed. The frequency of ozone concentration less than 200 microg/m3 is 96.88%. The ozone concentration has an obvious diurnal variation. The ozone concentration in the afternoon is higher than in the morning and in the evening. The maximum appears in June, when it is the strong solar radiation and high air-temperature. The weather conditions also influence the ozone concentration. The ozone concentration in clear day is higher than in rainy and cloudy day.

  1. 3D analysis of high ozone production rates observed during the ESCOMPTE campaign

    Science.gov (United States)

    Coll, Isabelle; Pinceloup, Stéphanie; Perros, Pascal E.; Laverdet, Gérard; Le Bras, Georges

    2005-03-01

    The development of environmental policies to reduce the ozone levels around large agglomerations requires a good understanding of the development of ozone episodes. In particular, it is necessary to know the location and photochemical activity of the plume where ozone is formed. Measurement campaigns make it possible not only to characterize the concentration fields of ozone and its precursors but also to identify the zones of strong ozone production, by means of specific measurements and kinetic calculations. The combination of the observation-based data with numerical simulations allows to better characterize photochemical pollution. This paper presents a study carried out within the ESCOMPTE program and based on the determination of ozone production rates by experimental and numerical methods: ground measurements of peroxy radicals, NO x at a rural site, airborne measurements of NO X and O 3, Eulerian modeling. The reported case is of particular interest since it corresponds to an episode with very different photochemical situations. The diurnal variations of the peroxy radical concentration are analyzed in relation to those of ozone and its precursors. Ozone production rates— P(O 3)-are studied over one particular day. The results show particularly high concentrations of RO 2+HO 2 at ground level (up to 200 pptv) under the influence of the urban and industrial plume, but also highlight very high production rates of ozone (60 to 80 ppbv h -1) a few tens of kilometers from the sources. The results show satisfactory agreement between the various approaches. Modeling provides a four-dimensional (4D) description of the plumes, in particular the relation between the ozone precursor concentrations and P(O 3) on the ground.

  2. Antarctic ozone loss in 1989-2010: evidence for ozone recovery?

    Science.gov (United States)

    Kuttippurath, J.; Lefèvre, F.; Pommereau, J.-P.; Roscoe, H. K.; Goutail, F.; Pazmiño, A.; Shanklin, J. D.

    2012-04-01

    We present a detailed estimation of chemical ozone loss in the Antarctic polar vortex from 1989 to 2010. The analyses include ozone loss estimates for 12 Antarctic ground-based (GB) stations. All GB observations show minimum ozone in the late September-early October period. Among the stations, the lowest minimum ozone values are observed at South Pole and the highest at Dumont d'Urville. The ozone loss starts by mid-June at the vortex edge and then progresses towards the vortex core with time. The loss intensifies in August-September, peaks by the end of September-early October, and recovers thereafter. The average ozone loss in the Antarctic is revealed to be about 33-50% in 1989-1992 in agreement with the increase in halogens during this period, and then stayed at around 48% due to saturation of the loss. The ozone loss in the warmer winters (e.g. 2002, and 2004) is lower (37-46%) and in the colder winters (e.g. 2003, and 2006) is higher (52-55%). Because of small inter-annual variability, the correlation between ozone loss and the volume of polar stratospheric clouds yields ~0.51. The GB ozone and ozone loss values are in good agreement with those found from the space-based observations of the Total Ozone Mapping Spectrometer/Ozone Monitoring Instrument (TOMS/OMI), the Global Ozone Monitoring Experiment (GOME), the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY), and the Aura Microwave Limb Sounder (MLS), where the differences are within ±5% and are mostly within the error bars of the measurements. The piece-wise linear trends computed from the September-November vortex average GB and TOMS/OMI ozone show about -4 to -5.6 DU (Dobson Unit) yr-1 in 1989-1996 and about +1 DU yr-1 in 1997-2010. The trend during the former period is significant at 95% confidence intervals, but the trend in 1997-2010 is significant only at 85% confidence intervals. Our analyses suggest a period of about 9-10 yr to get the first detectable ozone

  3. Monitoring of the ozone layer. Annual report 1997

    International Nuclear Information System (INIS)

    Braathen, Geir O.; Svenoee, Trond; Hansen, Georg H.; Dahlback, Arne

    1998-10-01

    The three stations in Oslo, Tromsoe and at Ny-Aalesund at Svalbard measure the total ozone levels and these show low monthly averages in 1997 compared to the long-term monthly averages. In Oslo the averages for January to April were 3-13 % below those from 1979 to 1989. Detailed measurements are presented. Analyses based on model calculations and measurements both in Norway and at other places are presented and show the low spring ozone values largely to be a result of chemical oxone decomposition. Particularly in 1997 the polar whirl lasted longer than usual. This lead to reduced ozone transport from the equator to the poles which normally is strongest in spring. At the same time the ozone was decomposed through natural processes where NO x is involved. The report concludes that the extremely low values registered are caused by a combination of chemical decomposition due to chlorofluorocarbons and halon and the particularly dynamic meteorological situation. A trend analysis for the period of 1979 to 1997 was carried out. The trend has been declining unevenly. In Oslo, Tromsoe and Ny-Aalesund the UV radiation from the sun is continually measured using GUV instrumentation. The measurements confirm that the main factors influencing the UV level are the height of the sun, the amount of clouds, the thickness of the ozone layer and the reflection properties at the earth surface. Monthly radiation doses are presented as well. Both at the Oslo and Tromsoe universities two ozone layer measuring instruments of the Dobson and Brewer types, are used. Instrumental comparisons are made. From the Bjoernoeya and the Gardermoen there are regularly lifted balloons which may reach a 35 km altitude carrying ozone probes. The ozone altitude distribution is registered. Similar measurements in the Antarctic show that the yearly ozone decomposition from September to November occurs at the heights of 14 to 24 km. Studies show there is extensive ozone decomposition in the Arctic as well

  4. Analysis of Ozone in Cloudy Versus Clear Sky Conditions

    Science.gov (United States)

    Strode, Sarah; Douglass, Anne; Ziemke, Jerald

    2016-01-01

    Convection impacts ozone concentrations by transporting ozone vertically and by lofting ozone precursors from the surface, while the clouds and lighting associated with convection affect ozone chemistry. Observations of the above-cloud ozone column (Ziemke et al., 2009) derived from the OMI instrument show geographic variability, and comparison of the above-cloud ozone with all-sky tropospheric ozone columns from OMI indicates important regional differences. We use two global models of atmospheric chemistry, the GMI chemical transport model (CTM) and the GEOS-5 chemistry climate model, to diagnose the contributions of transport and chemistry to observed differences in ozone between areas with and without deep convection, as well as differences in clean versus polluted convective regions. We also investigate how the above-cloud tropospheric ozone from OMI can provide constraints on the relationship between ozone and convection in a free-running climate simulation as well as a CTM.

  5. Surface ozone in China: present-day distribution and long-term changes

    Science.gov (United States)

    Xu, X.; Lin, W.; Xu, W.

    2017-12-01

    Reliable knowledge of spatio-temporal variations of surface ozone is highly needed to assess the impacts of ozone on human health, ecosystem and climate. Although regional distributions and trends of surface ozone in European and North American countries have been well characterized, little is known about the variability of surface ozone in many other countries, including China, where emissions of ozone precursors have been changing rapidly in recent decades. Here we present the first comprehensive description of present-day (2013-2017) distribution and long-term changes of surface ozone in mainland China. Recent ozone measurements from China's air quality monitoring network (AQMN) are analyzed to show present-day distributions of a few ozone exposure metrics for urban environment. Long-term measurements of ozone at six background sites, a rural site and an urban are used to study the trends of ozone in background, rural and urban air, respectively. The average levels of ozone at the AQMN sites (mainly urban) are close to those found at many European and North American sites. However, ozone at most of the sites shows very large diurnal and seasonal variations so that ozone nonattainment can occur in many cities, particularly those in the North China Plain (NCP), the south of Northeast China (NEC), the Yangtze River Delta (YRD), the Pearl River Delta (PRD), and the Sichuan Basin-Chongqing region (SCB). In all these regions, particularly in the NCP, the maximum daily 8-h average (MDA8) ozone concentration can significantly exceed the national limit (75 ppb). High annual sum of ozone means over 35 ppb (SOMO35) exist mainly in the NCP, NEC and YRD, with regional averages over 4000 ppb·d. Surface ozone has significantly increased at Waliguan (a baseline site in western China) and Shangdianzi (a background site in the NCP), and decreased in winter and spring at Longfengshan (a background site in Northeast China). No clear trend can be derived from long-term measurements

  6. NOx emissions trading: Precursor to future growth

    International Nuclear Information System (INIS)

    Colella, A.

    1993-01-01

    Title I of the Clean Air Act Amendments (CAAA) of 1990 specified the framework for enhanced regulation in ozone non-attainment areas with increasingly stringent requirements dependent on the area classification - marginal, moderate, serious, severe or extreme. Before the CAAA were passed, only volatile organic compounds (VOCs) were regulated as precursors to ozone formation, Now, by statute, emissions of nitrogen oxides (NO x ) are also regulated as ozone precursor. Under the CAAA, new sources and modifications of existing sources are subject to Title I permitting requirements in ozone non-attainment areas if emissions of NO x and/or VOCs exceed certain triggering levels. For many new or facility expansion projects, especially power generation, the NO x thresholds are easily exceeded thus triggering Title I non-attainment new source review which requires application of control technology to new equipment which results in the Lowest Achievable Emission Rate (LAER), and securing emission reductions either internally or from other major sources to offset the increased emission from the new or modified source. The selection of a LAER technology is generally within an applicant's control. An applicant can determine up-front the engineering and cost considerations associated with LAER technology is assessing a project's viability. However, without a clear source of emission offsets of a means to secure them, assessing project viability could be difficult if not impossible. No available emission offsets means no industrial growth. For sources of NO x undergoing Title I new source review, a regional or state banking system that facilitates NO x emissions trading is needed as a precursor to future growth. This paper presents an overview of EPA's Emissions Trading Policy and Title I new source review offset provisions. Industry's concerns about emissions trading and recommendations for future trading programs are presented

  7. Recent Biomass Burning in the Tropics and Related Changes in Tropospheric Ozone

    Science.gov (United States)

    Ziemke; Chandra, J. R. S.; Duncan, B. N.; Schoeberl, M. R.; Torres, O.; Damon, M. R.; Bhartia, P. K.

    2009-01-01

    Biomass burning is an important source of chemical precursors of tropospheric ozone. In the tropics, biomass burning produces ozone enhancements over broad regions of Indonesia, Africa, and South America including Brazil. Fires are intentionally set in these regions during the dry season each year to clear cropland and to clear land for human/industrial expansion. In Indonesia enhanced burning occurs during dry El Nino conditions such as in 1997 and 2006. These burning activities cause enhancement in atmospheric particulates and trace gases which are harmful to human health. Measurements from the Aura Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) from October 2004-November 2008 are used to evaluate the effects of biomass burning on tropical tropospheric ozone. These measurements show sizeable decreases approx.15-20% in ozone in Brazil during 2008 compared to 2007 which we attribute to the reduction in biomass burning. Three broad biomass burning regions in the tropics (South America including Brazil, western Africa, and Indonesia) were analyzed in the context of OMI/MLS measurements and the Global Modeling Initiative (GMI) chemical transport model developed at Goddard Space Flight Center. The results indicate that the impact of biomass burning on ozone is significant within and near the burning regions with increases of approx.10-25% in tropospheric column ozone relative to average background concentrations. The model suggests that about half of the increases in ozone from these burning events come from altitudes below 3 km. Globally the model indicates increases of approx.4-5% in ozone, approx.7-9% in NO, (NO+NO2), and approx.30-40% in CO.

  8. Sulfur dioxide emissions from Peruvian copper smelters detected by the ozone monitoring instrument

    NARCIS (Netherlands)

    Carn, S.A.; Krueger, A.J.; Krotkov, N.A.; Yang, Kai; Levelt, P.F.

    2007-01-01

    We report the first daily observations of sulfur dioxide (SO2) emissions from copper smelters by a satellite-borne sensor - the Ozone Monitoring Instrument (OMI) on NASA's EOS/Aura spacecraft. Emissions from two Peruvian smelters (La Oroya and Ilo) were detected in up to 80% of OMI overpasses

  9. Global and Seasonal Distributions of CHOCHO and HCHO Observed by the Ozone Monitoring Instrument on EOS Aura

    Science.gov (United States)

    Kurosu, T. P.; Fu, T.; Volkamer, R.; Millet, D. B.; Chance, K.

    2006-12-01

    Over the two years since its launch in July 2004, the Ozone Monitoring Instrument (OMI) on EOS Aura has demonstrated the capability to routinely monitor the volatile organic compounds (VOCs) formaldehyde (HCHO) and glyoxal (CHOCHO). OMI's daily global coverage and spatial resolution as high as 13x24 km provides a unique data set of these molecules for the study of air quality from space. We present the first study of global seasonal distributions of CHOCHO from space, derived from a year of OMI observations. CHOCHO distributions are compared to simultaneous retrievals of HCHO from OMI, providing a first indication of seasonally resolved ratios of these VOCs on a global scale. Satellite retrievals are compared to global simulations of HCHO and CHOCHO, based on current knowledge of sources and sinks, using the GEOS-Chem global chemistry and transport model. Formaldehyde is both directly emitted and also produced from the oxidation of many VOCs, notably biogenic isoprene, and is removed by photolysis and oxidation. Precursors of glyoxal include isoprene, monoterpenes, and aromatics from anthropogenic, biogenic, and biomass burning emissions; it is removed by photolysis, oxidation by OH, dry/wet deposition, and aerosol uptake. As a case study, satellite observations will also be compared to ground-based measurements taken during the Pearl River Delta 2006 field campaign near Guangzhou, China, where high glyoxal concentrations are frequently observed from space.

  10. Characterization of N-nitrosodimethylamine formation from the ozonation of ranitidine.

    Science.gov (United States)

    Lv, Juan; Wang, Lin; Li, Yongmei

    2017-08-01

    N-nitrosodimethylamine (NDMA) is an emerging disinfection by-product which is formed during water disinfection in the presence of amine-based precursors. Ranitidine, as one kind of amine-based pharmaceuticals, has been identified as NDMA precursor with high NDMA molar conversion during chloramination. This study focused on the characterization of NDMA formation during ozonation of ranitidine. Influences of operational variables (ozone dose, pH value) and water matrix on NDMA generation as well as ranitidine degradation were evaluated. The results indicate high reactivity of ranitidine with ozone. Dimethylamine (DMA) and NDMA were generated due to ranitidine oxidation. High pH value caused more NDMA accumulation. NDMA formation was inhibited under acid conditions (pH≤5) mainly due to the protonation of amines. Water matrix such as HCO 3 - and humic acid impacted NDMA generation due to OH scavenging. Compared with OH, ozone molecules dominated the productions of DMA and NDMA. However, OH was a critical factor in NDMA degradation. Transformation products of ranitidine during ozonation were identified using gas chromatography-mass spectrometry. Among these products, just DMA and N,N-dimethylformamide could contribute to NDMA formation due to the DMA group in the molecular structures. The NDMA formation pathway from ranitidine ozonation was also proposed. Copyright © 2017. Published by Elsevier B.V.

  11. Results of ozone measurements in Northern Germany: A case study

    Science.gov (United States)

    Schmidt, Manfred

    1994-01-01

    At most of the German ozone recording stations which have records over a sufficiently long period, the results of the summer months of 1989 showed the highest values since the beginning of the measurements. One of the reasons for this phenomenon was the high duration of sunshine in that summer; for example, in Potsdam near Berlin in May 1989 the sunshine duration was the highest in May since the beginning of the records in 1893. For that reason we selected this summer for a case study. The basis for the study was mainly the ozone measuring stations of the network of Lower Saxony and the Federal Office of Environment (Umweltbundesamt). The results of these summer measurements point to intense sources of ozone, probably in form of gaseous precursors, in the Middle German industrial areas near Leipzig and Halle and in Northwestern Czechoslovakia, with coal-mining, chemical and petrochemical industries, coking plants and others. The maps of average ozone concentrations, number or days with high ozone maxima, ozone-windroses of the stations, etc., suggest that these areas could be a main source of precursors and of photochemical ozone production in summer smog episodes in Central Europe. Stations on the North Sea coast, at which early ozone measurements were made by our institute in 1973/74 are compared with similarly located stations of the Lower Saxon network in 1989 and the results show a reversal of the ozone-windroses. In 1973/74, the highest ozone concentrations were correlated with wind directions from the sea while in 1989 these concentrations were correlated with directions from the continent. In the recent years, photochemical ozone production on the continent is probably predominant, while in former years the higher ozone content of the maritime subpolar air masses has been explained by stratospheric-tropospheric exchange.

  12. Application of validation data for assessing spatial interpolation methods for 8-h ozone or other sparsely monitored constituents

    International Nuclear Information System (INIS)

    Joseph, John; Sharif, Hatim O.; Sunil, Thankam; Alamgir, Hasanat

    2013-01-01

    The adverse health effects of high concentrations of ground-level ozone are well-known, but estimating exposure is difficult due to the sparseness of urban monitoring networks. This sparseness discourages the reservation of a portion of the monitoring stations for validation of interpolation techniques precisely when the risk of overfitting is greatest. In this study, we test a variety of simple spatial interpolation techniques for 8-h ozone with thousands of randomly selected subsets of data from two urban areas with monitoring stations sufficiently numerous to allow for true validation. Results indicate that ordinary kriging with only the range parameter calibrated in an exponential variogram is the generally superior method, and yields reliable confidence intervals. Sparse data sets may contain sufficient information for calibration of the range parameter even if the Moran I p-value is close to unity. R script is made available to apply the methodology to other sparsely monitored constituents. -- Highlights: •Spatial interpolation methods were tested for thousands of sparse ozone data sets. •A particular single-parameter ordinary kriging was found to be generally superior. •A Moran I p-value in the training set is not helpful in selecting the method. •The sum of the squares of the residuals is helpful in selecting the method. •R script is available for application to other sites and constituents. -- Spatial interpolation methods were compared for thousands of subsets of data for 8-h ozone using R script applicable to other constituents as well, and available from the authors

  13. Development of a sensitive passive sampler using indigotrisulfonate for the determination of tropospheric ozone.

    Science.gov (United States)

    Garcia, Gabriel; Allen, Andrew George; Cardoso, Arnaldo Alves

    2010-06-01

    A new sampling and analytical design for measurement of ambient ozone is presented. The procedure is based on ozone absorption and decoloration (at 600 nm) of indigotrisulfonate dye, where ozone adds itself across the carbon-carbon double bond of the indigo. A mean relative standard deviation of 8.6% was obtained using samplers exposed in triplicate, and a correlation coefficient (r) of 0.957 was achieved in parallel measurements using the samplers and a commercial UV ozone instrument. The devices were evaluated in a measurement campaign, mapping spatial and temporal trends of ozone concentrations in a region of southeast Brazil strongly influenced by seasonal agricultural biomass burning, with associated emissions of ozone precursors. Ozone concentrations were highest in rural areas and lowest at an urban site, due to formation during downwind transport and short-term depletion due to titration with nitric oxide. Ozone concentrations showed strong seasonal trends, due to the influences of precursor emissions, relative humidity and solar radiation intensity. Advantages of the technique include ease and speed of use, the ready availability of components, and excellent sensitivity. Achievable temporal resolution of ozone concentrations is 8 hours at an ambient ozone concentration of 3.8 ppb, or 2 hours at a concentration of 15.2 ppb.

  14. Trends of Ozone in Switzerland since 1992 (TROZOS)

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez, C.; Mathis, H.; Furger, M.; Prevot, A.S.H

    2004-07-01

    This work reports on the trends of the daily afternoon (noon to midnight) maximum ozone concentrations at 15 of the 16 stations of the Swiss air quality monitoring network (NABEL) during the period 1992-2002. The use of numerous meteorological parameters and additional data allowed a detailed seasonal analysis of the influence of the weather on the ozone maxima at the different stations. An analysis of covariance (ANCOVA) was performed separately for each station and season in order to detect the parameters which best explain the variability of the daily ozone maximum concentrations. During the warm seasons (summer and spring) the most explanatory parameters are those related to the ozone production, in particular the afternoon temperature. In winter, the most explanatory variables are the ones influencing the vertical mixing and thus the ozone destruction by titration with NO and dry deposition, like the afternoon global radiation. The trends of both the measured and meteorologically corrected ozone maxima were calculated. The year-to-year variability in the ozone maxima was lowered by a factor of 3 by the meteorological correction. Significantly positive trends of corrected ozone maxima of 0.3 - 1.1 ppb/year were found at the low altitude stations in winter and autumn as well as at Lausanne - urban station - in all the seasons, mainly due to the lower loss of ozone by reaction with NO as a consequence of the decreased emissions of primary pollutants during the 90s. This could be partially confirmed by the lower trends of O{sub X} (sum O{sub 3} of and NO{sub 2}) maxima compared to the trends in ozone maxima. The absence of negative trends of the median or mean ozone maxima north of the Alps in summer suggests that the decrease in the emissions of ozone precursors did not have a strong impact on the afternoon maximum ozone concentrations during the last decade. In contrast to the project TOSS (Trends of Ozone in Southern Switzerland), no significantly negative

  15. Trends of Ozone in Switzerland since 1992 (TROZOS)

    International Nuclear Information System (INIS)

    Ordonez, C.; Mathis, H.; Furger, M.; Prevot, A.S.H.

    2004-07-01

    This work reports on the trends of the daily afternoon (noon to midnight) maximum ozone concentrations at 15 of the 16 stations of the Swiss air quality monitoring network (NABEL) during the period 1992-2002. The use of numerous meteorological parameters and additional data allowed a detailed seasonal analysis of the influence of the weather on the ozone maxima at the different stations. An analysis of covariance (ANCOVA) was performed separately for each station and season in order to detect the parameters which best explain the variability of the daily ozone maximum concentrations. During the warm seasons (summer and spring) the most explanatory parameters are those related to the ozone production, in particular the afternoon temperature. In winter, the most explanatory variables are the ones influencing the vertical mixing and thus the ozone destruction by titration with NO and dry deposition, like the afternoon global radiation. The trends of both the measured and meteorologically corrected ozone maxima were calculated. The year-to-year variability in the ozone maxima was lowered by a factor of 3 by the meteorological correction. Significantly positive trends of corrected ozone maxima of 0.3 - 1.1 ppb/year were found at the low altitude stations in winter and autumn as well as at Lausanne - urban station - in all the seasons, mainly due to the lower loss of ozone by reaction with NO as a consequence of the decreased emissions of primary pollutants during the 90s. This could be partially confirmed by the lower trends of O X (sum O 3 of and NO 2 ) maxima compared to the trends in ozone maxima. The absence of negative trends of the median or mean ozone maxima north of the Alps in summer suggests that the decrease in the emissions of ozone precursors did not have a strong impact on the afternoon maximum ozone concentrations during the last decade. In contrast to the project TOSS (Trends of Ozone in Southern Switzerland), no significantly negative trends of ozone

  16. Is the ozone climate penalty robust in Europe?

    International Nuclear Information System (INIS)

    Colette, Augustin; Bessagnet, Bertrand; Meleux, Frédérik; Rouïl, Laurence; Andersson, Camilla; Engardt, Magnuz; Langner, Joakim; Baklanov, Alexander; Brandt, Jørgen; Christensen, Jesper H; Geels, Camilla; Hedegaard, Gitte B; Doherty, Ruth; Giannakopoulos, Christos; Katragkou, Eleni; Lei, Hang; Manders, Astrid; Melas, Dimitris; Sofiev, Mikhail; Soares, Joana

    2015-01-01

    Ozone air pollution is identified as one of the main threats bearing upon human health and ecosystems, with 25 000 deaths in 2005 attributed to surface ozone in Europe (IIASA 2013 TSAP Report #10). In addition, there is a concern that climate change could negate ozone pollution mitigation strategies, making them insufficient over the long run and jeopardising chances to meet the long term objective set by the European Union Directive of 2008 (Directive 2008/50/EC of the European Parliament and of the Council of 21 May 2008) (60 ppbv, daily maximum). This effect has been termed the ozone climate penalty. One way of assessing this climate penalty is by driving chemistry-transport models with future climate projections while holding the ozone precursor emissions constant (although the climate penalty may also be influenced by changes in emission of precursors). Here we present an analysis of the robustness of the climate penalty in Europe across time periods and scenarios by analysing the databases underlying 11 articles published on the topic since 2007, i.e. a total of 25 model projections. This substantial body of literature has never been explored to assess the uncertainty and robustness of the climate ozone penalty because of the use of different scenarios, time periods and ozone metrics. Despite the variability of model design and setup in this database of 25 model projection, the present meta-analysis demonstrates the significance and robustness of the impact of climate change on European surface ozone with a latitudinal gradient from a penalty bearing upon large parts of continental Europe and a benefit over the North Atlantic region of the domain. Future climate scenarios present a penalty for summertime (JJA) surface ozone by the end of the century (2071–2100) of at most 5 ppbv. Over European land surfaces, the 95% confidence interval of JJA ozone change is [0.44; 0.64] and [0.99; 1.50] ppbv for the 2041–2070 and 2071–2100 time windows, respectively

  17. Is the ozone climate penalty robust in Europe?

    Science.gov (United States)

    Colette, Augustin; Andersson, Camilla; Baklanov, Alexander; Bessagnet, Bertrand; Brandt, Jørgen; Christensen, Jesper H.; Doherty, Ruth; Engardt, Magnuz; Geels, Camilla; Giannakopoulos, Christos; Hedegaard, Gitte B.; Katragkou, Eleni; Langner, Joakim; Lei, Hang; Manders, Astrid; Melas, Dimitris; Meleux, Frédérik; Rouïl, Laurence; Sofiev, Mikhail; Soares, Joana; Stevenson, David S.; Tombrou-Tzella, Maria; Varotsos, Konstantinos V.; Young, Paul

    2015-08-01

    Ozone air pollution is identified as one of the main threats bearing upon human health and ecosystems, with 25 000 deaths in 2005 attributed to surface ozone in Europe (IIASA 2013 TSAP Report #10). In addition, there is a concern that climate change could negate ozone pollution mitigation strategies, making them insufficient over the long run and jeopardising chances to meet the long term objective set by the European Union Directive of 2008 (Directive 2008/50/EC of the European Parliament and of the Council of 21 May 2008) (60 ppbv, daily maximum). This effect has been termed the ozone climate penalty. One way of assessing this climate penalty is by driving chemistry-transport models with future climate projections while holding the ozone precursor emissions constant (although the climate penalty may also be influenced by changes in emission of precursors). Here we present an analysis of the robustness of the climate penalty in Europe across time periods and scenarios by analysing the databases underlying 11 articles published on the topic since 2007, i.e. a total of 25 model projections. This substantial body of literature has never been explored to assess the uncertainty and robustness of the climate ozone penalty because of the use of different scenarios, time periods and ozone metrics. Despite the variability of model design and setup in this database of 25 model projection, the present meta-analysis demonstrates the significance and robustness of the impact of climate change on European surface ozone with a latitudinal gradient from a penalty bearing upon large parts of continental Europe and a benefit over the North Atlantic region of the domain. Future climate scenarios present a penalty for summertime (JJA) surface ozone by the end of the century (2071-2100) of at most 5 ppbv. Over European land surfaces, the 95% confidence interval of JJA ozone change is [0.44; 0.64] and [0.99; 1.50] ppbv for the 2041-2070 and 2071-2100 time windows, respectively.

  18. Ionospheric earthquake precursors

    International Nuclear Information System (INIS)

    Bulachenko, A.L.; Oraevskij, V.N.; Pokhotelov, O.A.; Sorokin, V.N.; Strakhov, V.N.; Chmyrev, V.M.

    1996-01-01

    Results of experimental study on ionospheric earthquake precursors, program development on processes in the earthquake focus and physical mechanisms of formation of various type precursors are considered. Composition of experimental cosmic system for earthquake precursors monitoring is determined. 36 refs., 5 figs

  19. The operational cloud retrieval algorithms from TROPOMI on board Sentinel-5 Precursor

    Science.gov (United States)

    Loyola, Diego G.; Gimeno García, Sebastián; Lutz, Ronny; Argyrouli, Athina; Romahn, Fabian; Spurr, Robert J. D.; Pedergnana, Mattia; Doicu, Adrian; Molina García, Víctor; Schüssler, Olena

    2018-01-01

    This paper presents the operational cloud retrieval algorithms for the TROPOspheric Monitoring Instrument (TROPOMI) on board the European Space Agency Sentinel-5 Precursor (S5P) mission scheduled for launch in 2017. Two algorithms working in tandem are used for retrieving cloud properties: OCRA (Optical Cloud Recognition Algorithm) and ROCINN (Retrieval of Cloud Information using Neural Networks). OCRA retrieves the cloud fraction using TROPOMI measurements in the ultraviolet (UV) and visible (VIS) spectral regions, and ROCINN retrieves the cloud top height (pressure) and optical thickness (albedo) using TROPOMI measurements in and around the oxygen A-band in the near infrared (NIR). Cloud parameters from TROPOMI/S5P will be used not only for enhancing the accuracy of trace gas retrievals but also for extending the satellite data record of cloud information derived from oxygen A-band measurements, a record initiated with the Global Ozone Monitoring Experiment (GOME) on board the second European Remote-Sensing Satellite (ERS-2) over 20 years ago. The OCRA and ROCINN algorithms are integrated in the S5P operational processor UPAS (Universal Processor for UV/VIS/NIR Atmospheric Spectrometers), and we present here UPAS cloud results using the Ozone Monitoring Instrument (OMI) and GOME-2 measurements. In addition, we examine anticipated challenges for the TROPOMI/S5P cloud retrieval algorithms, and we discuss the future validation needs for OCRA and ROCINN.

  20. Assessment of ozone impacts on vegetation in southern Africa and directions for future research

    CSIR Research Space (South Africa)

    Van Tienhoven, AM

    2005-03-01

    Full Text Available in the high ozone levels measured at the beginning of the southern African summer.17,23,24 The concentrations of ozone precursors, the complex production and removal pro- cesses, and the short lifespan of ozone, mean that ozone concentration in the atmosphere... jointoformextensiveareasofchlorosisas the leaf ages. Damage to foliage can be extensive enough to cause complete loss ofleafycropssuchaslettuceandchicory.39 Visible symptoms of ozone effects must be interpreted with caution, particularly in field studies where interactions...

  1. Ozone from fireworks: Chemical processes or measurement interference?

    Science.gov (United States)

    Xu, Zheng; Nie, Wei; Chi, Xuguang; Huang, Xin; Zheng, Longfei; Xu, Zhengning; Wang, Jiaping; Xie, Yuning; Qi, Ximeng; Wang, Xinfeng; Xue, Likun; Ding, Aijun

    2018-08-15

    Fireworks have been identified as one ozone source by photolyzing NO 2 or O 2 and are believed to potentially be important for the nighttime ozone during firework events. In this study, we conducted both lab and field experiments to test two types of fireworks with low and high energy with the goal to distinguish whether the visible ozone signal during firework displays is real. The results suggest that previous understanding of the ozone formation mechanism during fireworks is misunderstood. Ultraviolet ray (UV)-based ozone monitors are interfered by aerosols and some specific VOCs. High-energy fireworks emit high concentrations of particular matters and low VOCs that the artificial ozone can be easily removed by an aerosol filter. Low-energy fireworks emit large amounts of VOCs mostly from the combustion of the cardboard from fireworks that largely interferes with the ozone monitor. Benzene and phenol might be major contributors to the artificial ozone signal. We further checked the nighttime ozone concentration in Jinan and Beijing, China, during Chinese New Year, a period with intense fireworks. A signal of 3-8ppbv ozone was detected and positively correlated to NO and SO 2 , suggesting a considerable influence of these chemicals in interfering with ambient ozone monitoring. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Temporal Characterisation of Ground-level Ozone Concentration in Klang Valley

    Science.gov (United States)

    Izzah Mohamad Hashim, Nur; Noor, Norazian Mohamed; Yasina Yusof, Sara

    2018-03-01

    In Malaysia, ground-level ozone (O3) is one of the most significant air pollutants due to the increasing sources of ozone precursors. Hence, the surface O3 concentration should have received substantial attention because of its negative effects to human health, vegetation and the environment. In this study, hourly air pollutants dataset (i.e O3, Carbon monoxide (CO), Nitrogen dioxide (NO2), Particulate matter (PM10), Non-methane hydrocarbon (NmHC), Sulphur dioxide (SO2)) and weather parameters (i.e. wind speed (WS), wind direction (WD), temperature (T), ultraviolet B (UVB)) for ten years period (2003-2012) in Klang Valley were selected for analysis in this study. Two monitoring stations were selected that are Petaling Jaya and Shah Alam. The aim of the study is to determine the diurnal variations of O3 concentrations according to the seasonal monsoon and the correlation between the ground-level O3 concentration and others parameter. A high concentration of ground-level O3 was observed during the first transition (April to May) for both of the stations. While at a low surface, O3 concentration was found out during the southwest monsoon within June to September. Pearson correlation was used to find the correlation between the O3 concentration and all other pollutants and weather parameters. Most of the relationship between O3concentrationswas positively correlated with NO2 and negative relationship was found out with NMHC. These results were expected since these pollutants are known as the O3 precursors. Besides that, O3 concentration and its precursors show a positive significant correlation with all meteorological factors except for relative humidity.

  3. Temporal Characterisation of Ground-level Ozone Concentration in Klang Valley

    Directory of Open Access Journals (Sweden)

    Mohamad Hashim Nur Izzah

    2018-01-01

    Full Text Available In Malaysia, ground-level ozone (O3 is one of the most significant air pollutants due to the increasing sources of ozone precursors. Hence, the surface O3 concentration should have received substantial attention because of its negative effects to human health, vegetation and the environment. In this study, hourly air pollutants dataset (i.e O3, Carbon monoxide (CO, Nitrogen dioxide (NO2, Particulate matter (PM10, Non-methane hydrocarbon (NmHC, Sulphur dioxide (SO2 and weather parameters (i.e. wind speed (WS, wind direction (WD, temperature (T, ultraviolet B (UVB for ten years period (2003-2012 in Klang Valley were selected for analysis in this study. Two monitoring stations were selected that are Petaling Jaya and Shah Alam. The aim of the study is to determine the diurnal variations of O3 concentrations according to the seasonal monsoon and the correlation between the ground-level O3 concentration and others parameter. A high concentration of ground-level O3 was observed during the first transition (April to May for both of the stations. While at a low surface, O3 concentration was found out during the southwest monsoon within June to September. Pearson correlation was used to find the correlation between the O3 concentration and all other pollutants and weather parameters. Most of the relationship between O3concentrationswas positively correlated with NO2 and negative relationship was found out with NMHC. These results were expected since these pollutants are known as the O3 precursors. Besides that, O3 concentration and its precursors show a positive significant correlation with all meteorological factors except for relative humidity.

  4. Research to connect the ozone monitor into irradiation system at Hanoi Irradiation Centre

    International Nuclear Information System (INIS)

    Le Van Huy; Pham Duy Duong; Nguyen Dinh Hung; Vu Quoc Dat

    2013-01-01

    Since 2006, in order to develop radiation technology, Vietnam Atomic Energy Institute has supported Hanoi Irradiation Centre a Project titled: Upgrading the irradiation facility. According to the Project, equipment have been replaced by a new one so that the facility could be suitable for treatment of products. The facility was designed and produced by the former Russia experts. Under normal operating conditions, we are protected by shielding, detection systems, and safety procedures. A system of interlocks prevents unauthorized entry into the radiation chamber when the source is exposed. However, interlocks system have not been warning and preventing ozone gas that can affect human health. So we are having an upgrade as connecting the ozone monitor into irradiation system at Hanoi Irradiation Centre. (author)

  5. Ozone Gardens for the Citizen Scientist

    Science.gov (United States)

    Pippin, Margaret; Reilly, Gay; Rodjom, Abbey; Malick, Emily

    2016-01-01

    NASA Langley partnered with the Virginia Living Museum and two schools to create ozone bio-indicator gardens for citizen scientists of all ages. The garden at the Marshall Learning Center is part of a community vegetable garden designed to teach young children where food comes from and pollution in their area, since most of the children have asthma. The Mt. Carmel garden is located at a K-8 school. Different ozone sensitive and ozone tolerant species are growing and being monitored for leaf injury. In addition, CairClip ozone monitors were placed in the gardens and data are compared to ozone levels at the NASA Langley Chemistry and Physics Atmospheric Boundary Layer Experiment (CAPABLE) site in Hampton, VA. Leaf observations and plant measurements are made two to three times a week throughout the growing season.

  6. Application of validation data for assessing spatial interpolation methods for 8-h ozone or other sparsely monitored constituents.

    Science.gov (United States)

    Joseph, John; Sharif, Hatim O; Sunil, Thankam; Alamgir, Hasanat

    2013-07-01

    The adverse health effects of high concentrations of ground-level ozone are well-known, but estimating exposure is difficult due to the sparseness of urban monitoring networks. This sparseness discourages the reservation of a portion of the monitoring stations for validation of interpolation techniques precisely when the risk of overfitting is greatest. In this study, we test a variety of simple spatial interpolation techniques for 8-h ozone with thousands of randomly selected subsets of data from two urban areas with monitoring stations sufficiently numerous to allow for true validation. Results indicate that ordinary kriging with only the range parameter calibrated in an exponential variogram is the generally superior method, and yields reliable confidence intervals. Sparse data sets may contain sufficient information for calibration of the range parameter even if the Moran I p-value is close to unity. R script is made available to apply the methodology to other sparsely monitored constituents. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. The impact of large scale biomass production on ozone air pollution in Europe

    NARCIS (Netherlands)

    Beltman, J.B.; Hendriks, C.; Tum, M.; Schaap, M.

    2013-01-01

    Tropospheric ozone contributes to the removal of air pollutants from the atmosphere but is itself a pollutant that is harmful to human health and vegetation. Biogenic isoprene emissions are important ozone precursors, and therefore future changes in land use that change isoprene emissions are likely

  8. Ozone and NOx chemistry in the eastern US: evaluation of CMAQ/CB05 with satellite (OMI data

    Directory of Open Access Journals (Sweden)

    T. P. Canty

    2015-10-01

    Full Text Available Regulatory air quality models, such as the Community Multiscale Air Quality model (CMAQ, are used by federal and state agencies to guide policy decisions that determine how to best achieve adherence with National Ambient Air Quality Standards for surface ozone. We use observations of ozone and its important precursor NO2 to test the representation of the photochemistry and emission of ozone precursors within CMAQ. Observations of tropospheric column NO2 from the Ozone Monitoring Instrument (OMI, retrieved by two independent groups, show that the model overestimates urban NO2 and underestimates rural NO2 under all conditions examined for July and August 2011 in the US Northeast. The overestimate of the urban to rural ratio of tropospheric column NO2 for this baseline run of CMAQ (CB05 mechanism, mobile NOx emissions from the National Emissions Inventory; isoprene emissions from MEGAN v2.04 suggests this model may underestimate the importance of interstate transport of NOx. This CMAQ simulation leads to a considerable overestimate of the 2-month average of 8 h daily maximum surface ozone in the US Northeast, as well as an overestimate of 8 h ozone at AQS sites during days when the state of Maryland experienced NAAQS exceedances. We have implemented three changes within CMAQ motivated by OMI NO2 as well as aircraft observations obtained in July 2011 during the NASA DISCOVER-AQ campaign: (a the modeled lifetime of organic nitrates within CB05 has been reduced by a factor of 10, (b emissions of NOx from mobile sources has been reduced by a factor of 2, and (c isoprene emissions have been reduced by using MEGAN v2.10 rather than v2.04. Compared to the baseline simulation, the CMAQ run using all three of these changes leads to considerably better simulation of column NO2 in both urban and rural areas, better agreement with the 2-month average of daily 8 h maximum ozone in the US Northeast, fewer number of false positives of an ozone exceedance

  9. Uncertainties in models of tropospheric ozone based on Monte Carlo analysis: Tropospheric ozone burdens, atmospheric lifetimes and surface distributions

    Science.gov (United States)

    Derwent, Richard G.; Parrish, David D.; Galbally, Ian E.; Stevenson, David S.; Doherty, Ruth M.; Naik, Vaishali; Young, Paul J.

    2018-05-01

    Recognising that global tropospheric ozone models have many uncertain input parameters, an attempt has been made to employ Monte Carlo sampling to quantify the uncertainties in model output that arise from global tropospheric ozone precursor emissions and from ozone production and destruction in a global Lagrangian chemistry-transport model. Ninety eight quasi-randomly Monte Carlo sampled model runs were completed and the uncertainties were quantified in tropospheric burdens and lifetimes of ozone, carbon monoxide and methane, together with the surface distribution and seasonal cycle in ozone. The results have shown a satisfactory degree of convergence and provide a first estimate of the likely uncertainties in tropospheric ozone model outputs. There are likely to be diminishing returns in carrying out many more Monte Carlo runs in order to refine further these outputs. Uncertainties due to model formulation were separately addressed using the results from 14 Atmospheric Chemistry Coupled Climate Model Intercomparison Project (ACCMIP) chemistry-climate models. The 95% confidence ranges surrounding the ACCMIP model burdens and lifetimes for ozone, carbon monoxide and methane were somewhat smaller than for the Monte Carlo estimates. This reflected the situation where the ACCMIP models used harmonised emissions data and differed only in their meteorological data and model formulations whereas a conscious effort was made to describe the uncertainties in the ozone precursor emissions and in the kinetic and photochemical data in the Monte Carlo runs. Attention was focussed on the model predictions of the ozone seasonal cycles at three marine boundary layer stations: Mace Head, Ireland, Trinidad Head, California and Cape Grim, Tasmania. Despite comprehensively addressing the uncertainties due to global emissions and ozone sources and sinks, none of the Monte Carlo runs were able to generate seasonal cycles that matched the observations at all three MBL stations. Although

  10. Ozone measurements 2010. [EMEP Co-operative Programme for Monitoring and Evaluation of the Long-range Transmission of Air Pollutants in Europe

    Energy Technology Data Exchange (ETDEWEB)

    Hjellbrekke, Anne-Gunn; Solberg, Sverre; Fjaeraa, Ann Mari

    2012-07-01

    From the Introduction: Ozone is a natural constituent of the atmosphere and plays a vital role in many atmospheric processes. However, man-made emissions of volatile organic compounds and nitrogen oxides have increased the photochemical formation of ozone in the troposphere. Until the end of the 1960s the problem was basically believed to be one of the big cities and their immediate surroundings. In the 1970s, however, it was found that the problem of photochemical oxidant formation is much more widespread. The ongoing monitoring of ozone at rural sites throughout Europe shows that episodes of high concentrations of ground-level ozone occur over most parts of the continent every summer. During these episodes the ozone concentrations can reach values above ambient air quality standards over large regions and lead to adverse effects for human health and vegetation. Historical records of ozone measurements in Europe and North America indicate that in the last part of the nineteenth century the values were only about half of the average surface ozone concentrations measured in the same regions during the last 10-15 years (Bojkov, 1986; Volz and Kley, 1988).The formation of ozone is due to a large number of photochemical reactions taking place in the atmosphere and depends on the temperature, humidity and solar radiation as well as the primary emissions of nitrogen oxides and volatile organic compounds. Together with the non-linear relationships between the primary emissions and the ozone formation, these effects complicates the abatement strategies for ground-level ozone and makes photochemical models crucial in addition to the monitoring data. The 1999 Gothenburg Protocol is designed for a joint abatement of acidification, eutrophication and ground-level ozone. It has been estimated that once the Protocol is implemented, the number of days with excessive ozone levels will be halved and that the exposure of vegetation to excessive ozone levels will be 44% down on 1990

  11. Tropospheric ozone and aerosols in climate agreements: scientific and political challenges

    International Nuclear Information System (INIS)

    Rypdal, Kristin; Berntsen, Terje; Fuglestvedt, Jan S.; Aunan, Kristin; Torvanger, Asbjorn; Stordal, Frode; Pacyna, Jozef M.; Nygaard, Lynn P.

    2005-01-01

    In addition to the six greenhouse gases included in the Kyoto Protocol, the tropospheric ozone precursors CO, NMVOC and NO x and the aerosols/aerosol precursors black carbon, organic carbon and SO 2 also play significant roles in climate change. The aim of this paper is to review some of the main scientific and political challenges associated with incorporating tropospheric ozone and aerosol precursors into climate agreements, and to discuss how these challenges have a bearing on the design of future climate agreements. We argue that the optimal policy design for a particular substance depends on a combination of scientific and political concerns. We look particularly at regional climate effects, negative forcing, metrics (measuring climate effects against other gases on a common scale), political attractiveness, and verification and compliance. We systematically review the existing knowledge on these issues, explore their impact on policy design, and conclude that, with current scientific knowledge, CO and NMVOC could conceivably be included in a global climate agreement, either in a basket with the long-lived greenhouse gases or in a separate basket, while NO x and aerosols might be regulated more appropriately through regional agreements with links to a global agreement. However, the complexity and fairness implications of including tropospheric ozone precursors and aerosols might negatively affect the political feasibility of a future agreement

  12. Tropospheric Ozone Assessment Report: Database and Metrics Data of Global Surface Ozone Observations

    Directory of Open Access Journals (Sweden)

    Martin G. Schultz

    2017-10-01

    Full Text Available In support of the first Tropospheric Ozone Assessment Report (TOAR a relational database of global surface ozone observations has been developed and populated with hourly measurement data and enhanced metadata. A comprehensive suite of ozone data products including standard statistics, health and vegetation impact metrics, and trend information, are made available through a common data portal and a web interface. These data form the basis of the TOAR analyses focusing on human health, vegetation, and climate relevant ozone issues, which are part of this special feature. Cooperation among many data centers and individual researchers worldwide made it possible to build the world's largest collection of 'in-situ' hourly surface ozone data covering the period from 1970 to 2015. By combining the data from almost 10,000 measurement sites around the world with global metadata information, new analyses of surface ozone have become possible, such as the first globally consistent characterisations of measurement sites as either urban or rural/remote. Exploitation of these global metadata allows for new insights into the global distribution, and seasonal and long-term changes of tropospheric ozone and they enable TOAR to perform the first, globally consistent analysis of present-day ozone concentrations and recent ozone changes with relevance to health, agriculture, and climate. Considerable effort was made to harmonize and synthesize data formats and metadata information from various networks and individual data submissions. Extensive quality control was applied to identify questionable and erroneous data, including changes in apparent instrument offsets or calibrations. Such data were excluded from TOAR data products. Limitations of 'a posteriori' data quality assurance are discussed. As a result of the work presented here, global coverage of surface ozone data for scientific analysis has been significantly extended. Yet, large gaps remain in the surface

  13. Chemical processes related to net ozone tendencies in the free troposphere

    Science.gov (United States)

    Bozem, Heiko; Butler, Tim M.; Lawrence, Mark G.; Harder, Hartwig; Martinez, Monica; Kubistin, Dagmar; Lelieveld, Jos; Fischer, Horst

    2017-09-01

    Ozone (O3) is an important atmospheric oxidant, a greenhouse gas, and a hazard to human health and agriculture. Here we describe airborne in situ measurements and model simulations of O3 and its precursors during tropical and extratropical field campaigns over South America and Europe, respectively. Using the measurements, net ozone formation/destruction tendencies are calculated and compared to 3-D chemistry-transport model simulations. In general, observation-based net ozone tendencies are positive in the continental boundary layer and the upper troposphere at altitudes above ˜ 6 km in both environments. On the other hand, in the marine boundary layer and the middle troposphere, from the top of the boundary layer to about 6-8 km altitude, net O3 destruction prevails. The ozone tendencies are controlled by ambient concentrations of nitrogen oxides (NOx). In regions with net ozone destruction the available NOx is below the threshold value at which production and destruction of O3 balance. While threshold NO values increase with altitude, in the upper troposphere NOx concentrations are generally higher due to the integral effect of convective precursor transport from the boundary layer, downward transport from the stratosphere and NOx produced by lightning. Two case studies indicate that in fresh convective outflow of electrified thunderstorms net ozone production is enhanced by a factor 5-6 compared to the undisturbed upper tropospheric background. The chemistry-transport model MATCH-MPIC generally reproduces the pattern of observation-based net ozone tendencies but mostly underestimates the magnitude of the net tendency (for both net ozone production and destruction).

  14. Strategy for reducing ozone levels in the northeast United States

    International Nuclear Information System (INIS)

    Bradley, M.

    1992-01-01

    In the northeast USA, ozone episodes are frequent during the summer; most of these episodes last 3-4 days. The duration and frequency of these episodes is mainly determined by weather conditions. The persistence of ozone episodes in the region is explained by the fact that emissions of ozone precursors (nitrogen oxides (NOx) and volatile organic compounds (VOC)) are like those of other regions of the USA affected by acute ozone problems. The population density, industry, and use of automobiles are other factors contributing to the difficulty of maintaining acceptable ozone levels. The ozone problem is especially severe in the New York metropolitan area and most of New Jersey. Strategies for combating ozone precursors have relied entirely on reducing emissions of VOCs, while little has been done to reduce NOx, except for automobile emissions. The Clean Air Act of 1990 provides for significant reductions of NOx and VOC from mobile sources and insists on VOC emissions reductions from stationary sources. In California, stricter emission standards for VOC and NOx have been implemented for new vehicles, requiring wider use of low- or zero-emission vehicles. The Northeast States for Coordinated Air Use Management (NESCAUM) organization, formed by the state agencies responsible for air quality, is aiding the northeast states to evaluate the advantages of adopting California standards for vehicles. Twelve northeast states propose to adopt the Californian low-emission vehicle program and are examining other options such as reformulated gasolines, improved maintenance and verification programs, and measures to reduce the number of miles travelled. 1 fig., 1 tab

  15. Effect of sequences of ozone and nitrogen dioxide on plant dry ...

    African Journals Online (AJOL)

    Ozone (O3) is the most important gaseous air pollutant in the world because of its adverse effects on vegetation in general and crop plants in particular. Since nitrogen dioxide (NO2) is a precursor of ozone, studying the implication of sequences of these two gases is very important. Hence, the effects of sequences of ...

  16. Aerosol optical thickness retrieval over land and water using Global Ozone Monitoring Experiment (GOME) data

    NARCIS (Netherlands)

    Kusmierczyk-Michulec, J.; Leeuw, G. de

    2005-01-01

    An algorithm for the retrieval of the aerosol optical thickness over land and over water from Global Ozone Monitoring Experiment (GOME) data is presented. The cloud fraction in the GOME pixels is determined using the Fast Retrieval Scheme for Clouds From the Oxygen A Band (FRESCO) algorithm. Surface

  17. Passive monitoring techniques for evaluating atmospheric ozone and nitrogen exposure and deposition to California ecosystems

    Science.gov (United States)

    Mark E. Fenn; Andrzej Bytnerowicz; Susan L. Schilling

    2018-01-01

    Measuring the exposure of ecosystems to ecologically relevant pollutants is needed for evaluating ecosystem effects and to identify regions and resources at risk. In California, ozone (O3) and nitrogen (N) pollutants are of greatest concern for ecological effects. "Passive" monitoring methods have been developed to obtain spatially...

  18. Chemical and climatic drivers of radiative forcing due to changes in stratospheric and tropospheric ozone over the 21st century

    Science.gov (United States)

    Banerjee, Antara; Maycock, Amanda C.; Pyle, John A.

    2018-02-01

    The ozone radiative forcings (RFs) resulting from projected changes in climate, ozone-depleting substances (ODSs), non-methane ozone precursor emissions and methane between the years 2000 and 2100 are calculated using simulations from the UM-UKCA chemistry-climate model (UK Met Office's Unified Model containing the United Kingdom Chemistry and Aerosols sub-model). Projected measures to improve air-quality through reductions in non-methane tropospheric ozone precursor emissions present a co-benefit for climate, with a net global mean ozone RF of -0.09 W m-2. This is opposed by a positive ozone RF of 0.05 W m-2 due to future decreases in ODSs, which is driven by an increase in tropospheric ozone through stratosphere-to-troposphere transport of air containing higher ozone amounts. An increase in methane abundance by more than a factor of 2 (as projected by the RCP8.5 scenario) is found to drive an ozone RF of 0.18 W m-2, which would greatly outweigh the climate benefits of non-methane tropospheric ozone precursor reductions. A small fraction (˜ 15 %) of the ozone RF due to the projected increase in methane results from increases in stratospheric ozone. The sign of the ozone RF due to future changes in climate (including the radiative effects of greenhouse gases, sea surface temperatures and sea ice changes) is shown to be dependent on the greenhouse gas emissions pathway, with a positive RF (0.05 W m-2) for RCP4.5 and a negative RF (-0.07 W m-2) for the RCP8.5 scenario. This dependence arises mainly from differences in the contribution to RF from stratospheric ozone changes. Considering the increases in tropopause height under climate change causes only small differences (≤ |0.02| W m-2) for the stratospheric, tropospheric and whole-atmosphere RFs.

  19. The operational cloud retrieval algorithms from TROPOMI on board Sentinel-5 Precursor

    Directory of Open Access Journals (Sweden)

    D. G. Loyola

    2018-01-01

    Full Text Available This paper presents the operational cloud retrieval algorithms for the TROPOspheric Monitoring Instrument (TROPOMI on board the European Space Agency Sentinel-5 Precursor (S5P mission scheduled for launch in 2017. Two algorithms working in tandem are used for retrieving cloud properties: OCRA (Optical Cloud Recognition Algorithm and ROCINN (Retrieval of Cloud Information using Neural Networks. OCRA retrieves the cloud fraction using TROPOMI measurements in the ultraviolet (UV and visible (VIS spectral regions, and ROCINN retrieves the cloud top height (pressure and optical thickness (albedo using TROPOMI measurements in and around the oxygen A-band in the near infrared (NIR. Cloud parameters from TROPOMI/S5P will be used not only for enhancing the accuracy of trace gas retrievals but also for extending the satellite data record of cloud information derived from oxygen A-band measurements, a record initiated with the Global Ozone Monitoring Experiment (GOME on board the second European Remote-Sensing Satellite (ERS-2 over 20 years ago. The OCRA and ROCINN algorithms are integrated in the S5P operational processor UPAS (Universal Processor for UV/VIS/NIR Atmospheric Spectrometers, and we present here UPAS cloud results using the Ozone Monitoring Instrument (OMI and GOME-2 measurements. In addition, we examine anticipated challenges for the TROPOMI/S5P cloud retrieval algorithms, and we discuss the future validation needs for OCRA and ROCINN.

  20. The potential near-source ozone impacts of upstream oil and gas industry emissions.

    Science.gov (United States)

    Olaguer, Eduardo P

    2012-08-01

    Increased drilling in urban areas overlying shale formations and its potential impact on human health through decreased air quality make it important to estimate the contribution of oil and gas activities to photochemical smog. Flares and compressor engines used in natural gas operations, for example, are large sources not only of NOx but also offormaldehyde, a hazardous air pollutant and powerful ozone precursor We used a neighborhood scale (200 m horizontal resolution) three-dimensional (3D) air dispersion model with an appropriate chemical mechanism to simulate ozone formation in the vicinity ofa hypothetical natural gas processing facility, based on accepted estimates of both regular and nonroutine emissions. The model predicts that, under average midday conditions in June, regular emissions mostly associated with compressor engines may increase ambient ozone in the Barnett Shale by more than 3 ppb beginning at about 2 km downwind of the facility, assuming there are no other major sources of ozone precursors. Flare volumes of 100,000 cubic meters per hour ofnatural gas over a period of 2 hr can also add over 3 ppb to peak 1-hr ozone somewhatfurther (>8 km) downwind, once dilution overcomes ozone titration and inhibition by large flare emissions of NOx. The additional peak ozone from the hypothetical flare can briefly exceed 10 ppb about 16 km downwind. The enhancements of ambient ozone predicted by the model are significant, given that ozone control strategy widths are of the order of a few parts per billion. Degrading the horizontal resolution of the model to 1 km spuriously enhances the simulated ozone increases by reducing the effectiveness of ozone inhibition and titration due to artificial plume dilution.

  1. Evaluation of ozone profile and tropospheric ozone retrievals from GEMS and OMI spectra

    Directory of Open Access Journals (Sweden)

    J. Bak

    2013-02-01

    Full Text Available South Korea is planning to launch the GEMS (Geostationary Environment Monitoring Spectrometer instrument into the GeoKOMPSAT (Geostationary Korea Multi-Purpose SATellite platform in 2018 to monitor tropospheric air pollutants on an hourly basis over East Asia. GEMS will measure backscattered UV radiances covering the 300–500 nm wavelength range with a spectral resolution of 0.6 nm. The main objective of this study is to evaluate ozone profiles and stratospheric column ozone amounts retrieved from simulated GEMS measurements. Ozone Monitoring Instrument (OMI Level 1B radiances, which have the spectral range 270–500 nm at spectral resolution of 0.42–0.63 nm, are used to simulate the GEMS radiances. An optimal estimation-based ozone profile algorithm is used to retrieve ozone profiles from simulated GEMS radiances. Firstly, we compare the retrieval characteristics (including averaging kernels, degrees of freedom for signal, and retrieval error derived from the 270–330 nm (OMI and 300–330 nm (GEMS wavelength ranges. This comparison shows that the effect of not using measurements below 300 nm on retrieval characteristics in the troposphere is insignificant. However, the stratospheric ozone information in terms of DFS decreases greatly from OMI to GEMS, by a factor of ∼2. The number of the independent pieces of information available from GEMS measurements is estimated to 3 on average in the stratosphere, with associated retrieval errors of ~1% in stratospheric column ozone. The difference between OMI and GEMS retrieval characteristics is apparent for retrieving ozone layers above ~20 km, with a reduction in the sensitivity and an increase in the retrieval errors for GEMS. We further investigate whether GEMS can resolve the stratospheric ozone variation observed from high vertical resolution Earth Observing System (EOS Microwave Limb Sounder (MLS. The differences in stratospheric ozone profiles between GEMS and MLS are comparable to those

  2. Global Ozone Distribution relevant to Human Health: Metrics and present day levels from the Tropospheric Ozone Assessment Report (TOAR)

    Science.gov (United States)

    Fleming, Z. L.; Doherty, R. M.; von Schneidemesser, E.; Cooper, O. R.; Malley, C.; Colette, A.; Xu, X.; Pinto, J. P.; Simpson, D.; Schultz, M. G.; Hamad, S.; Moola, R.; Solberg, S.; Feng, Z.

    2017-12-01

    Using stations from the TOAR surface ozone database, this study quantifies present-day global and regional distributions of five ozone metrics relevant for both short-term and long-term human exposure. These metrics were explored at ozone monitoring sites globally, and re-classified for this project as urban or non-urban using population densities and night-time lights. National surface ozone limit values are usually related to an annual number of exceedances of daily maximum 8-hour running mean (MDA8), with many countries not even having any ozone limit values. A discussion and comparison of exceedances in the different ozone metrics, their locations and the seasonality of exceedances provides clues as to the regions that potentially have more serious ozone health implications. Present day ozone levels (2010-2014) have been compared globally and show definite geographical differences (see Figure showing the annual 4th highest MDA8 for present day ozone for all non-urban stations). Higher ozone levels are seen in western compared to eastern US, and between southern and northern Europe, and generally higher levels in east Asia. The metrics reflective of peak concentrations show highest values in western North America, southern Europe and East Asia. A number of the metrics show similar distributions of North-South gradients, most prominent across Europe and Japan. The interquartile range of the regional ozone metrics was largest in East Asia, higher for urban stations in Asia but higher for non-urban stations in Europe and North America. With over 3000 monitoring stations included in this analysis and despite the higher densities of monitoring stations in Europe, north America and East Asia, this study provides the most comprehensive global picture to date of surface ozone levels in terms of health-relevant metrics.

  3. How is ozone pollution reducing our food supply?

    Science.gov (United States)

    Wilkinson, Sally; Mills, Gina; Illidge, Rosemary; Davies, William J

    2012-01-01

    Ground-level ozone pollution is already decreasing global crop yields (from ∼2.2-5.5% for maize to 3.9-15% and 8.5-14% for wheat and soybean, respectively), to differing extents depending on genotype and environmental conditions, and this problem is predicted to escalate given climate change and increasing ozone precursor emissions in many areas. Here a summary is provided of how ozone pollution affects yield in a variety of crops, thus impacting global food security. Ozone causes visible injury symptoms to foliage; it induces early senescence and abscission of leaves; it can reduce stomatal aperture and thereby carbon uptake, and/or directly reduce photosynthetic carbon fixation; it can moderate biomass growth via carbon availability or more directly; it can decrease translocation of fixed carbon to edible plant parts (grains, fruits, pods, roots) due either to reduced availability at source, redirection to synthesis of chemical protectants, or reduced transport capabilities via phloem; decreased carbon transport to roots reduces nutrient and water uptake and affects anchorage; ozone can moderate or bring forward flowering and induce pollen sterility; it induces ovule and/or grain abortion; and finally it reduces the ability of some genotypes to withstand other stresses such as drought, high vapour pressure deficit, and high photon flux density via effects on stomatal control. This latter point is emphasized here, given predictions that atmospheric conditions conducive to drought formation that also give rise to intense precursor emission events will become more severe over the coming decades.

  4. Analysis of Ozone And CO2 Profiles Measured At A Diary Facility

    Science.gov (United States)

    Ogunjemiyo, S. O.; Hasson, A. S.; Ashkan, S.; Steele, J.; Shelton, T.

    2015-12-01

    Ozone and carbon dioxide are both greenhouse gasses in the planetary boundary layer. Ozone is a harmful secondary pollutant in the troposphere produced mostly during the day when there is a photochemical reaction in which primary pollutant precursors such as nitrous oxide (NOx) or volatile organic compounds (VOC's) mix with sunlight. As with most pollutants in the lower troposphere, both ozone and carbon dioxide vary in spatial and temporal scale depending on sources of pollution, environmental conditions and the boundary layer dynamics. Among the several factors that influence ozone variation, the seasonal changes in meteorological parameters and availability of ozone precursors are crucial because they control ozone formation and decay. Understanding how the difference in emission sources affect vertical transport of ozone and carbon dioxide is considered crucial to the improvement of their regional inventory sources. The purpose of this study is to characterize vertical transport of ozone and carbon at a diary facility. The study was conducted in the summer of 2011 and 2012 at a commercial dairy facility in Central California and involved profile measurements of ozone and CO2 using electrochemical ozonesondes, meteorological sondes and CO2 probe tethered to a 9 cubic meters helium balloon. On each day of the data collection, multiple balloon launches were made over a period representing different stages of the boundary layer development. The results show ozone and CO2 profiles display different characteristics. Regardless of the time of the day, the CO2 concentration decreases with height with a sharp gradient near the surface that is strengthened by a stable atmospheric condition, a feature suggesting the surface as the source. On the other hand, ozone profiles show greater link to the evolution of the lower boundary layer. Ozone profiles display unique features indicating ozone destruction near the surface. This unusual near the surface, observed even in the

  5. Vertical ozone characteristics in urban boundary layer in Beijing.

    Science.gov (United States)

    Ma, Zhiqiang; Xu, Honghui; Meng, Wei; Zhang, Xiaoling; Xu, Jing; Liu, Quan; Wang, Yuesi

    2013-07-01

    Vertical ozone and meteorological parameters were measured by tethered balloon in the boundary layer in the summer of 2009 in Beijing, China. A total of 77 tethersonde soundings were taken during the 27-day campaign. The surface ozone concentrations measured by ozonesondes and TEI 49C showed good agreement, albeit with temporal difference between the two instruments. Two case studies of nocturnal secondary ozone maxima are discussed in detail. The development of the low-level jet played a critical role leading to the observed ozone peak concentrations in nocturnal boundary layer (NBL). The maximum of surface ozone was 161.7 ppbv during the campaign, which could be attributed to abundant precursors storage near surface layer at nighttime. Vertical distribution of ozone was also measured utilizing conventional continuous analyzers on 325-m meteorological observation tower. The results showed the NBL height was between 47 and 280 m, which were consistent with the balloon data. Southerly air flow could bring ozone-rich air to Beijing, and the ozone concentrations exceeded the China's hourly ozone standard (approximately 100 ppb) above 600 m for more than 12 h.

  6. Rates and regimes of photochemical ozone production over Central East China in June 2006: a box model analysis using comprehensive measurements of ozone precursors

    Directory of Open Access Journals (Sweden)

    Y. Kanaya

    2009-10-01

    Full Text Available An observation-based box model approach was undertaken to estimate concentrations of OH, HO2, and RO2 radicals and the net photochemical production rate of ozone at the top of Mount Tai, located in the middle of Central East China, in June 2006. The model calculation was constrained by the measurements of O3, H2O, CO, NO, NO2, hydrocarbon, HCHO, and CH3CHO concentrations, and temperature and J values. The net production rate of ozone was estimated to be 6.4 ppb h−1 as a 6-h average (09:00–15:00 CST, suggesting 58±37 ppb of ozone is produced in one day. Thus the daytime buildup of ozone recorded at the mountain top as ~23 ppb on average is likely affected by in situ photochemistry as well as by the upward transport of polluted air mass in the daytime. On days with high ozone concentrations (hourly values exceeding 100 ppb at least once, in situ photochemistry was more active than it was on low ozone days, suggesting that in situ photochemistry is an important factor controlling ozone concentrations. Sensitivity model runs for which different NOx and hydrocarbon concentrations were assumed suggested that the ozone production occurred normally under NOx-limited conditions, with some exceptional periods (under volatile-organic-compound-limited conditions in which there was fresh pollution. We also examined the possible influence of the heterogeneous loss of gaseous HO2 radicals in contact with aerosol particle surfaces on the rate and regimes of ozone production.

  7. Near-ground ozone source attributions and outflow in central eastern China during MTX2006

    Science.gov (United States)

    Li, J.; Wang, Z.; Akimoto, H.; Yamaji, K.; Takigawa, M.; Pochanart, P.; Liu, Y.; Tanimoto, H.; Kanaya, Y.

    2008-12-01

    A 3-D regional chemical transport model, the Nested Air Quality Prediction Model System (NAQPMS), with an on-line tracer tagging module was used to study the source of the near-ground (pollutants, and it captured highly polluted and clean cases well. The simulated near-ground ozone level over CEC was 60-85 ppbv (parts per billion by volume), which was higher than values in Japan and over the North Pacific (20-50 ppbv). The simulated tagged tracer data indicated that the regional-scale transport of chemically produced ozone over other areas in CEC contributed to the greatest fraction (49%) of the near-ground mean ozone at Mt. Tai in June; in situ photochemistry contributed only 12%. Due to high anthropogenic and biomass burning emissions that occurred in the southern part of the CEC, the contribution to ground ozone levels from this area played the most important role (32.4 ppbv, 37.9% of total ozone) in the monthly mean ozone concentration at Mt. Tai; values reached 59 ppbv (62%) on 6-7 June 2006. The monthly mean horizontal distribution of chemically produced ozone from various ozone production regions indicated that photochemical reactions controlled the spatial distribution of O3 over CEC. The regional-scale transport of pollutants also played an important role in the spatial and temporal distribution of ozone over CEC. Chemically produced ozone from the southern part of the study region can be transported northeastwardly to the northern rim of CEC; the mean contribution was 5-10 ppbv, and it reached 25 ppbv during high ozone events. Studies of the outflow of CEC ozone and its precursors, as well as their influences and contributions to the ozone level over adjacent regions/countries, revealed that the contribution of CEC ozone to mean ozone mixing ratios over the Korean Peninsula and Japan was 5-15 ppbv, of which about half was due to the direct transport of ozone from CEC and half was produced locally by ozone precursors transported from CEC.

  8. Investigation of vertical and horizontal transport processes and their influence on the concentration of aerosols and ozone over the greater Berlin area

    Science.gov (United States)

    Reimer, E.; Kerschbaumer, A.; Beekmann, M.; Neißner, F.

    2003-04-01

    Urban emissions of particulate matter and precursors of ozone are very important in relation to the EU-council directives and national pollution abatement strategies. Knowledge about the contribution of anthropogenic urban sources and about long range transport of polluted air to local concentrations is needed for any reduction strategy. Thus, within the German Atmospheric Research Program AFO2000 a project has been started to investigate the formation and transport of PM10/PM2.5 in the greater Berlin area by sampling and analysing PM, using LIDAR as well as physico-chemical measurements to determine density, partical size distribution and chemical composition of the aerosol. Participants are: Freie Universität Berlin, Institute for Meteorology BTU Cottbus, Air Chemistry Department Elight Laser Systems GmbH Freie Universität Berlin, Physics Department Environmental Administration, Berlin Government with an additional PM campaign Measurements at central Berlin monitoring stations exceed standard PM10 tresholds. Therefore, it is important to get a better knowledge about PM sources within and outside the city. Long term applications of the chemical transport model with an aerosol-module REM3/Calgrid is used to explain transport, formation and deposition processes. Backward and forward trajectories are used to determine source/receptor relationships between the observations and European wide emission maps for ozone, precursors and PM10 and PM2,5 by correlation between observed primary aerosols in Berlin and possible sources. The measurements obtained within the project are also used to validate REM3/Calgrid with special respect to SO4, NO3, NH4 and ozone precursors.

  9. The impact of large scale biomass production on ozone air pollution in Europe

    OpenAIRE

    Beltman, Joost B.; Hendriks, Carlijn; Tum, Markus; Schaap, Martijn

    2013-01-01

    Tropospheric ozone contributes to the removal of air pollutants from the atmosphere but is itself a pollutant that is harmful to human health and vegetation. Biogenic isoprene emissions are important ozone precursors, and therefore future changes in land use that change isoprene emissions are likely to affect atmospheric ozone concentrations. Here, we use the chemical transport model LOTOS-EUROS (dedicated to the regional modeling of trace gases in Europe) to study a scenario in which 5% of t...

  10. Experimental monitoring of ozone production in a PET cyclotron facility

    International Nuclear Information System (INIS)

    Zanibellato, L.; Cicoria, G.; Pancaldi, D.; Boschi, S.; Mostacci, D.; Marengo, M.

    2010-01-01

    Ozone produced from radiolytic processes was investigated as a possible health hazard in the working environment at the University Hospital 'S.Orsola-Malpighi' PET facility. Intense radiation fields can generate ozone, known to be the most toxic gas produced by ionizing radiation around a particle accelerator. To evaluate ozone concentration in air, two different measurement campaigns were conducted with passive diffusion detectors. Comparison of the results with the concentration limits recommended by American Conference of Governmental Industrial Hygienists (ACGIH) demonstrated that ozone poses no health hazard to workers around a biomedical cyclotron.

  11. Climate Prediction Center (CPC)Stratospheric Monitoring Ozone Blended Analysis

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A 3-D global ozone mixing ratio (ppm) and total column ozone (DU) dataset analyzed from daily Solar Backscatter Ultraviolet Instrument(SBUV/2) and TIROS Operational...

  12. N-nitrosodimethylamine (NDMA) formation during ozonation of N,N-dimethylhydrazine compounds: Reaction kinetics, mechanisms, and implications for NDMA formation control.

    Science.gov (United States)

    Lim, Sungeun; Lee, Woongbae; Na, Soyoung; Shin, Jaedon; Lee, Yunho

    2016-11-15

    Compounds with N,N-dimethylhydrazine moieties ((CH 3 ) 2 N-N-) form N-nitrosodimethylamine (NDMA) during ozonation, but the relevant reaction chemistry is hitherto poorly understood. This study investigated the reaction kinetics and mechanisms of NDMA formation during ozonation of unsymmetrical dimethylhydrazine (UDMH) and daminozide (DMZ) as structural model N,N-dimethylhydrazine compounds. The reaction of ozone with these NDMA precursor compounds was fast, and k O3 at pH 7 was 2 × 10 6  M -1  s -1 for UDMH and 5 × 10 5  M -1  s -1 for DMZ. Molar NDMA yields (i.e., Δ[NDMA]/Δ[precursor] × 100) were 84% and 100% for UDMH and DMZ, respectively, determined at molar ozone dose ratio ([O 3 ] 0 /[precursor] 0 ) of ≥4 in the presence of tert-butanol as hydroxyl radical (OH) scavenger. The molar NDMA yields decreased significantly in the absence of tert-butanol, indicating OH formation and its subsequent reaction with the parent precursors forming negligible NDMA. The k OH at pH 7 was 4.9 × 10 9  M -1  s -1 and 3.4 × 10 9  M -1  s -1 for UDMH and DMZ, respectively. Reaction mechanisms are proposed in which an ozone adduct is formed at the nitrogen next to N,N-dimethylamine which decomposes via homolytic and heterolytic cleavages of the -N + -O-O-O - bond, forming NDMA as a final product. The heterolytic cleavage pathway explains the significant OH formation via radical intermediates. Overall, significant NDMA formation was found to be unavoidable during ozonation or even O 3 /H 2 O 2 treatment of waters containing N,N-dimethylhydrazine compounds due to their rapid reaction with ozone forming NDMA with high yield. Thus, source control or pre-treatment of N,N-dimethylhydrazine precursors and post-treatment of NDMA are proposed as the mitigation options. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Chemical and climatic drivers of radiative forcing due to changes in stratospheric and tropospheric ozone over the 21st century

    Directory of Open Access Journals (Sweden)

    A. Banerjee

    2018-02-01

    Full Text Available The ozone radiative forcings (RFs resulting from projected changes in climate, ozone-depleting substances (ODSs, non-methane ozone precursor emissions and methane between the years 2000 and 2100 are calculated using simulations from the UM-UKCA chemistry–climate model (UK Met Office's Unified Model containing the United Kingdom Chemistry and Aerosols sub-model. Projected measures to improve air-quality through reductions in non-methane tropospheric ozone precursor emissions present a co-benefit for climate, with a net global mean ozone RF of −0.09 W m−2. This is opposed by a positive ozone RF of 0.05 W m−2 due to future decreases in ODSs, which is driven by an increase in tropospheric ozone through stratosphere-to-troposphere transport of air containing higher ozone amounts. An increase in methane abundance by more than a factor of 2 (as projected by the RCP8.5 scenario is found to drive an ozone RF of 0.18 W m−2, which would greatly outweigh the climate benefits of non-methane tropospheric ozone precursor reductions. A small fraction (∼ 15 % of the ozone RF due to the projected increase in methane results from increases in stratospheric ozone. The sign of the ozone RF due to future changes in climate (including the radiative effects of greenhouse gases, sea surface temperatures and sea ice changes is shown to be dependent on the greenhouse gas emissions pathway, with a positive RF (0.05 W m−2 for RCP4.5 and a negative RF (−0.07 W m−2 for the RCP8.5 scenario. This dependence arises mainly from differences in the contribution to RF from stratospheric ozone changes. Considering the increases in tropopause height under climate change causes only small differences (≤ |0.02| W m−2 for the stratospheric, tropospheric and whole-atmosphere RFs.

  14. California Baseline Ozone Transport Study (CABOTS): Ozonesonde Measurements

    Science.gov (United States)

    Eiserloh, A. J., Jr.; Chiao, S.; Spitze, J.; Cauley, S.; Clark, J.; Roberts, M.

    2016-12-01

    Because the EPA recently lowered the ambient air quality standard for the 8-hr average of ozone (O3) to70 ppbv, California must continue to achieve significant reductions in ozone precursor emissions and prepare for new State Implementation Plans (SIP) to demonstrate how ground-level ambient ozone will be reduced below the new health-based standard. Prior studies suggest that background levels of ozone traveling across the Pacific Ocean can significantly influence surface ozone throughout California, particularly during the spring. Evidence has been presented indicating that background levels of ozone continue to increase in the western United States over the recent few decades, implying more ozone exceedances in the future. To better understand the contributions of the external natural and anthropogenic pollution sources as well as atmospheric processes for surface ozone concentrations in California during the spring and summer months, the California Baseline Ozone Transport Study (CABOTS) has been established. One major goal of CABOTS is to implement near daily ozonesonde measurements along the California Coast to quantify background ozone aloft before entering the State during high ozone season. CABOTS has been ongoing from May through August of 2016 launching ozonesondes from Bodega Bay and Half Moon Bay, California. The temporal progression of ozonesonde measurements and subsequent analysis of the data will be discussed with a focus on the contribution of background ozone to surface ozone sites inland as well as likely origins of layers aloft. Comparisons of current ozonesondes versus prior ozonesonde studies of California will also be performed. A few selected cases of high ozone layers moving onshore from different sources will be discussed as well.

  15. Characteristics of intercontinental transport of tropospheric ozone from Africa to Asia

    Science.gov (United States)

    Han, Han; Liu, Jane; Yuan, Huiling; Zhuang, Bingliang; Zhu, Ye; Wu, Yue; Yan, Yuhan; Ding, Aijun

    2018-03-01

    In this study, we characterize the transport of ozone from Africa to Asia through the analysis of the simulations of a global chemical transport model, GEOS-Chem, from 1987 to 2006. The receptor region Asia is defined within 5-60° N and 60-145° E, while the source region Africa is within 35° S-15° N and 20° W-55° E and within 15-35° N and 20° W-30° E. The ozone generated in the African troposphere from both natural and anthropogenic sources is tracked through tagged ozone simulation. Combining this with analysis of trajectory simulations using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model, we find that the upper branch of the Hadley cell connects with the subtropical westerlies in the Northern Hemisphere (NH) to form a primary transport pathway from Africa to Asia in the middle and upper troposphere throughout the year. The Somali jet that runs from eastern Africa near the equator to the Indian subcontinent in the lower troposphere is the second pathway that appears only in NH summer. The influence of African ozone mainly appears over Asia south of 40° N. The influence shows strong seasonality, varying with latitude, longitude, and altitude. In the Asian upper troposphere, imported African ozone is largest from March to May around 30° N (12-16 ppbv) and lowest during July-October around 10° N ( ˜ 2 ppbv). In the Asian middle and lower troposphere, imported African ozone peaks in NH winter between 20 and 25° N. Over 5-40° N, the mean fractional contribution of imported African ozone to the overall ozone concentrations in Asia is largest during NH winter in the middle troposphere ( ˜ 18 %) and lowest in NH summer throughout the tropospheric column ( ˜ 6 %). This seasonality mainly results from the collective effects of the ozone precursor emissions in Africa and meteorology and chemistry in Africa, in Asia and along the transport pathways. The seasonal swing of the Hadley circulation and subtropical westerlies along the

  16. Method to determine the sticking coefficient of precursor molecules in atomic layer deposition

    International Nuclear Information System (INIS)

    Rose, M.; Bartha, J.W.

    2009-01-01

    A method to determine the sticking coefficient of precursor molecules used in atomic layer deposition (ALD) will be introduced. The sticking coefficient is an interesting quantity for comparing different ALD processes and reactors but it cannot be observed easily. The method relies on free molecular flow in nanoscale cylindrical holes. The sticking coefficient is determined for tetrakis(dimethylamino)titanium in combination with ozone. The proposed method can be applied independent of the type of reactor, precursor delivery system and precursors.

  17. Residential ozone and lung function in the elderly

    DEFF Research Database (Denmark)

    Braeuner, Elvira V.; Karottki, Dorina Gabriela; Frederiksen, Marie

    2016-01-01

    elderly non-smokers. Indoor ozone was measured passively in homes, while urban background outdoor ozone was monitored continuously at a fixed monitoring station located on the roof of the 20-m high university H.C. Ørsteds campus building in a park area. Lung function was measured at baseline as well...

  18. Ground-level ozone: Our new environmental policy

    International Nuclear Information System (INIS)

    Schiff, H.

    1991-01-01

    The environmental problem of ground level ozone is discussed, and the Canadian strategy for dealing with it is explained. Ozone in the troposphere can cause serious health problems in susceptible persons, and is estimated to cause up to $70 million in crop damage per year. The Canadian Council of Ministers of the Environment (CCME) Plan calls for less than 82 ppB by volume of ozone in any one-hour period in all areas of Canada by 2005. Three areas of Canada regularly exceed this value: the Lower Frazer valley in British Columbia, Saint John in New Brunswick, and the Windsor-Quebec corridor along the lower Great Lakes and the St. Lawrence River. Ozone is formed by a photochemical reaction of ammonia gases, nitrogen oxides, hydrogen sulfide or sulfur dioxide. Historically, ozone control has concentrated on controlling hydrocarbon emissions, but to little effect. In most locations close to large cities, ozone production is nitrogen oxide-limited, and the most recent models predict that the best strategy for ozone reduction requires the simultaneous reduction of both hydrocarbons and nitrogen oxides. The CCME Management Plan suggests that the 82 ppB ozone target will require a reduction of 40-50% in nitrogen oxide emissions. The Windsor end of the Windsor-Quebec corridor is dominated by transport of ozone and precursors from the USA, particularly Detroit and Cleveland, so Canadian controls alone are unlikely to solve the problem. For the rest of the corridor, nitrogen oxide control is likely to be most effective in urban areas. 1 fig

  19. Potential of future operational missions sentinel 4 and 5 for atmospheric monitoring and science (CAMELOT).

    Science.gov (United States)

    Levelt, P. F.; Veefkind, J. P.

    2010-05-01

    Dedicated atmospheric chemistry observations from space have been made for over 30 years now, starting with the SBUV and TOMS measurements of the ozone layer. Since then huge progress has been made, improving the accuracy of the measurements, extending the amount of constituents, and by sensing not only the stratosphere, but the last five to ten years also the troposphere. The potential to operational monitor the atmosphere, following the meteorological community, came within reach. At the same time, the importance for society of regular operational environmental measurements, related to the ozone layer, air quality and climate change, became apparent, amongst others resulting in the EU initiative Global Monitoring for Environment and Security (GMES) In order to prepare the operational missions in the context of the GMES, ESA took the initiative to further study the user requirements for the Sentinel 4 and 5 (precursor) missions. The Sentinel 4 and 5 (precursor) missions are dedicated operational missions to monitor the atmospheric composition in the 2013-2020 timeframe and onward. The user requirements for the sentinel missions focus on monitoring the atmosphere from an environmental point of view (ozone layer, air quality and climate). ESA's CAMELOT (Composition of the Atmospheric Mission concEpts and SentineL Observation Techniques) study is the follow-on study to ESA's CAPACITY study finished in 2005. The general objective of the CAMELOT study is to further contribute to the definition of the air quality and climate protocol monitoring parts of the GMES Sentinel 4 and 5 missions. CAMELOT consists of a large European consortium formed by 9 European institutes (KNMI (lead), RAL, U.Leicester, SRON, FMI, BIRA-IASB, CNR-IFAC,NOVELTIS and RIU-U.Koeln). In the presentation an overview will give a short overview of the CAMELOT study, including some specific results for combined retrievals, cloud statistics for different orbit geometries and retrievals for several orbit

  20. Ozone Promotes Chloropicrin Formation by Oxidizing Amines to Nitro Compounds.

    Science.gov (United States)

    McCurry, Daniel L; Quay, Amanda N; Mitch, William A

    2016-02-02

    Chloropicrin formation has been associated with ozonation followed by chlorination, but the reaction pathway and precursors have been poorly characterized. Experiments with methylamine demonstrated that ozonation converts methylamine to nitromethane at ∼100% yield. Subsequent chlorination converts nitromethane to chloropicrin at ∼50% yield under the conditions evaluated. Similarly high yields from other primary amines were limited to those with functional groups on the β-carbon (e.g., the carboxylic acid in glycine) that facilitate carbon-carbon bond cleavage to release nitromethyl anion. Secondary amines featuring these reactive primary amines as functional groups (e.g., secondary N-methylamines) formed chloropicrin at high yields, likely by facile dealkylation to release the primary nitro compound. Chloropicrin yields from tertiary amines were low. Natural water experiments, including derivatization to transform primary and secondary amines to less reactive carbamate functional groups, indicated that primary and secondary amines were the dominant chloropicrin precursors during ozonation/chlorination. Ozonation followed by chlorination of the primary amine side chain of lysine demonstrated low yields (∼0.2%) of chloropicrin, but high yields (∼17%) of dichloronitrolysine, a halonitroalkane structural analogue to chloropicrin. However, chloropicrin yields increased and dichloronitrolysine yields decreased in the absence of hydroxyl radical scavengers, suggesting that future research should characterize the potential occurrence of such halonitroalkane analogues relative to natural radical scavenger (e.g., carbonate) concentrations.

  1. Surface ozone variation at Bhubaneswar and intra-corelationship ...

    Indian Academy of Sciences (India)

    availability of ozone precursors control its forma- tion and decay ... izer and food processing industries along with ther- mal power ... radic growth of different industries such as cement, ...... Miller J, Preston E and Weinstein L 1982 Assessment of ... measurements at urban coastal site Chennai, in India;. J. Hazard. Mater.

  2. Interactive ozone and methane chemistry in GISS-E2 historical and future climate simulations

    Directory of Open Access Journals (Sweden)

    D. T. Shindell

    2013-03-01

    Full Text Available The new generation GISS climate model includes fully interactive chemistry related to ozone in historical and future simulations, and interactive methane in future simulations. Evaluation of ozone, its tropospheric precursors, and methane shows that the model captures much of the large-scale spatial structure seen in recent observations. While the model is much improved compared with the previous chemistry-climate model, especially for ozone seasonality in the stratosphere, there is still slightly too rapid stratospheric circulation, too little stratosphere-to-troposphere ozone flux in the Southern Hemisphere and an Antarctic ozone hole that is too large and persists too long. Quantitative metrics of spatial and temporal correlations with satellite datasets as well as spatial autocorrelation to examine transport and mixing are presented to document improvements in model skill and provide a benchmark for future evaluations. The difference in radiative forcing (RF calculated using modeled tropospheric ozone versus tropospheric ozone observed by TES is only 0.016 W m−2. Historical 20th Century simulations show a steady increase in whole atmosphere ozone RF through 1970 after which there is a decrease through 2000 due to stratospheric ozone depletion. Ozone forcing increases throughout the 21st century under RCP8.5 owing to a projected recovery of stratospheric ozone depletion and increases in methane, but decreases under RCP4.5 and 2.6 due to reductions in emissions of other ozone precursors. RF from methane is 0.05 to 0.18 W m−2 higher in our model calculations than in the RCP RF estimates. The surface temperature response to ozone through 1970 follows the increase in forcing due to tropospheric ozone. After that time, surface temperatures decrease as ozone RF declines due to stratospheric depletion. The stratospheric ozone depletion also induces substantial changes in surface winds and the Southern Ocean circulation, which may play a role in

  3. Destruction of disinfection byproducts and their precursors in swimming pool water by combined UV treatment and ozonation

    DEFF Research Database (Denmark)

    Cheema, Waqas Akram; Kaarsholm, Kamilla Marie Speht; Andersen, Henrik Rasmus

    Both UV treatment and ozonation are used to reduce different types of disinfection byproducts (DBP) in swimming pools. UV treatment is most common as it is particularly efficient in removing the repulsive chlorine like smelling chloramines (combined chlorine). UV treatment of a pool water increased...... chlorine reactivity and formation of chlor-organic DBP such as trihalomethanes. Based on the similar selective reactivity of ozone and chlorine we hypothesized that the created reactivity towards chlorine by UV treatment of dissolved organic matter in pool water might also be expressed as an increased...... reactivity towards ozone and that ozonation might saturate the chlorine reactivity created by UV treatment and mitigate the increased DBP formation. By experimentally treating pool water samples, we found that UV treatment makes pool water highly reactive to ozone. The created reactivity towards chlorine...

  4. Comparison of N-nitrosodimethylamine formation mechanisms from dimethylamine during chloramination and ozonation: A computational study

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yong Dong, E-mail: ydliu@bjut.edu.cn; Zhong, Rugang

    2017-01-05

    Highlights: • NDMA formation mechanisms from dimethylamine in chloramination/ozonation were reinvestigated by G4 method. • The reactivity order of halo-/hydroxyl-amines reacting with dimethylamine is NHCl{sub 2} ∼ NHBrCl > NH{sub 2}Cl >> NH{sub 2}OH. • Nitrene compound is an important intermediate to form NDMA in oxidation reaction. • Oxidation of unsymmetrical dimethylhydrazine by O{sub 2} is significantly less feasible compared to that by O{sub 3}. • The amines containing the second nitrogen source are potential NDMA precursors in ozonation. - Abstract: N-nitrosodimethylamine (NDMA) as a disinfection by-product has recently become the focus of considerable research interest due to its unusually high carcinogenicity. In this study, the formation mechanisms of NDMA from dimethylamine (DMA) during chloramination and ozonation were investigated by using the quantum chemical G4 method. The reactivity of haloamines and hydroxylamine reacting with DMA was found in the order: NHCl{sub 2} ∼ NHBrCl (Br{sup -}leaving) > NHBr{sub 2} > NH{sub 2}Cl ∼ NH{sub 2}Br >> NH{sub 2}OH. This offers a theoretical support for the experimentally proposed mechanism that dimethylamine reacts with NHCl{sub 2} rather than NH{sub 2}Cl to form chlorinated unsymmetrical dimethylhydrazine intermediate and the existence of bromochloramine in the presence of bromide during chloramination, and explains the observation that NDMA yield during ozonation is much lower than that during chloramination. Importantly, an N,N-dimethylaminonitrene was found to be a significant intermediate to form NDMA in oxidation reactions by molecular oxygen and ozone. Additionally, results suggest that the amines containing the second nitrogen source directly connecting or close to the N-(CH{sub 3}){sub 2} moiety are potential significant NDMA precursors upon ozonation. The findings of this study are helpful for expanding the knowledge of NDMA formation mechanism, and predicting potential NDMA precursors

  5. Study: Ozone Layer's Future Linked Strongly to Changes in Climate

    Science.gov (United States)

    balloon to measure of the vertical profile of the ozone layer. NOAA scientists launch an ozonesonde via balloon to measure of the vertical profile of the ozone layer. NOAA releases ozonesondes at eight sites to continuously monitor stratospheric ozone. Download here. (Credit: NOAA) The ozone layer - the thin

  6. Removal of Ozone by Urban and Peri-Urban Forests: Evidence from Laboratory, Field, and Modeling Approaches

    Science.gov (United States)

    Carlo Calfapietra; Arianna Morani; Gregorio Sgrigna; Sara Di Giovanni; Valerio Muzzini; Emanuele Pallozzi; Gabriele Guidolotti; David Nowak; Silvano Fares

    2016-01-01

    A crucial issue in urban environments is the interaction between urban trees and atmospheric pollution, particularly ozone (O3). Ozone represents one of the most harmful pollutants in urban and peri-urban environments, especially in warm climates. Besides the large interest in reducing anthropogenic and biogenic precursors of O3...

  7. WRF-Chem simulated surface ozone over south Asia during the pre-monsoon: effects of emission inventories and chemical mechanisms

    Directory of Open Access Journals (Sweden)

    A. Sharma

    2017-12-01

    Full Text Available We evaluate numerical simulations of surface ozone mixing ratios over the south Asian region during the pre-monsoon season, employing three different emission inventories in the Weather Research and Forecasting model with Chemistry (WRF-Chem with the second-generation Regional Acid Deposition Model (RADM2 chemical mechanism: the Emissions Database for Global Atmospheric Research – Hemispheric Transport of Air Pollution (EDGAR-HTAP, the Intercontinental Chemical Transport Experiment phase B (INTEX-B and the Southeast Asia Composition, Cloud, Climate Coupling Regional Study (SEAC4RS. Evaluation of diurnal variability in modelled ozone compared to observational data from 15 monitoring stations across south Asia shows the model ability to reproduce the clean, rural and polluted urban conditions over this region. In contrast to the diurnal average, the modelled ozone mixing ratios during noontime, i.e. hours of intense photochemistry (11:30–16:30 IST – Indian Standard Time – UTC +5:30, are found to differ among the three inventories. This suggests that evaluations of the modelled ozone limited to 24 h average are insufficient to assess uncertainties associated with ozone buildup. HTAP generally shows 10–30 ppbv higher noontime ozone mixing ratios than SEAC4RS and INTEX-B, especially over the north-west Indo-Gangetic Plain (IGP, central India and southern India. The HTAP simulation repeated with the alternative Model for Ozone and Related Chemical Tracers (MOZART chemical mechanism showed even more strongly enhanced surface ozone mixing ratios due to vertical mixing of enhanced ozone that has been produced aloft. Our study indicates the need to also evaluate the O3 precursors across a network of stations and the development of high-resolution regional inventories for the anthropogenic emissions over south Asia accounting for year-to-year changes to further reduce uncertainties in modelled ozone over this region.

  8. WRF-Chem simulated surface ozone over south Asia during the pre-monsoon: effects of emission inventories and chemical mechanisms

    Science.gov (United States)

    Sharma, Amit; Ojha, Narendra; Pozzer, Andrea; Mar, Kathleen A.; Beig, Gufran; Lelieveld, Jos; Gunthe, Sachin S.

    2017-12-01

    We evaluate numerical simulations of surface ozone mixing ratios over the south Asian region during the pre-monsoon season, employing three different emission inventories in the Weather Research and Forecasting model with Chemistry (WRF-Chem) with the second-generation Regional Acid Deposition Model (RADM2) chemical mechanism: the Emissions Database for Global Atmospheric Research - Hemispheric Transport of Air Pollution (EDGAR-HTAP), the Intercontinental Chemical Transport Experiment phase B (INTEX-B) and the Southeast Asia Composition, Cloud, Climate Coupling Regional Study (SEAC4RS). Evaluation of diurnal variability in modelled ozone compared to observational data from 15 monitoring stations across south Asia shows the model ability to reproduce the clean, rural and polluted urban conditions over this region. In contrast to the diurnal average, the modelled ozone mixing ratios during noontime, i.e. hours of intense photochemistry (11:30-16:30 IST - Indian Standard Time - UTC +5:30), are found to differ among the three inventories. This suggests that evaluations of the modelled ozone limited to 24 h average are insufficient to assess uncertainties associated with ozone buildup. HTAP generally shows 10-30 ppbv higher noontime ozone mixing ratios than SEAC4RS and INTEX-B, especially over the north-west Indo-Gangetic Plain (IGP), central India and southern India. The HTAP simulation repeated with the alternative Model for Ozone and Related Chemical Tracers (MOZART) chemical mechanism showed even more strongly enhanced surface ozone mixing ratios due to vertical mixing of enhanced ozone that has been produced aloft. Our study indicates the need to also evaluate the O3 precursors across a network of stations and the development of high-resolution regional inventories for the anthropogenic emissions over south Asia accounting for year-to-year changes to further reduce uncertainties in modelled ozone over this region.

  9. Multiparameter monitoring of short-term earthquake precursors and its physical basis. Implementation in the Kamchatka region

    Directory of Open Access Journals (Sweden)

    Pulinets Sergey

    2016-01-01

    Full Text Available We apply experimental approach of the multiparameter monitoring of short-term earthquake precursors which reliability was confirmed by the Lithosphere-Atmosphere-Ionosphere Coupling (LAIC model created recently [1]. A key element of the model is the process of Ion induced Nucleation (IIN and formation of cluster ions occurring as a result of the ionization of near surface air layer by radon emanating from the Earth's crust within the earthquake preparation zone. This process is similar to the formation of droplet’s embryos for cloud formation under action of galactic cosmic rays. The consequence of this process is the generation of a number of precursors that can be divided into two groups: a thermal and meteorological, and b electromagnetic and ionospheric. We demonstrate elements of prospective monitoring of some strong earthquakes in Kamchatka region and statistical results for the Chemical potential correction parameter for more than 10 years of observations for earthquakes with M≥6. As some experimental attempt, the data of Kamchatka volcanoes monitoring will be demonstrated.

  10. Monitoring of soil radon by SSNTD in Eastern India in search of possible earthquake precursor.

    Science.gov (United States)

    Deb, Argha; Gazi, Mahasin; Ghosh, Jayita; Chowdhury, Saheli; Barman, Chiranjib

    2018-04-01

    The present paper deals with monitoring soil radon-222 concentration at two different locations, designated Site A and Site B, 200 m apart at Jadavpur University campus, Kolkata, India, with a view to find possible precursors for the earthquakes that occurred within a few hundred kilometers from the monitoring site. The solid state nuclear track detector CR-39 has been used for detection of radon gas coming out from soil. Radon-222 time series at both locations during the period August 2012-December 2013 have been analysed. Distinct anomalies in the soil radon time series have been observed for seven earthquakes of magnitude greater than 4.0 M that occurred during this time. Of these, radon anomalies for two earthquakes have been observed at both locations A and B. Absence of anomalies for some other earthquakes has been discussed, and the observations have been compared with some earthquake precursor models. Copyright © 2018. Published by Elsevier Ltd.

  11. Ozone pollution and ozone biomonitoring in European cities. Part I: Ozone concentrations and cumulative exposure indices at urban and suburban sites

    DEFF Research Database (Denmark)

    Klumpp, A.; Ansel, W.; Klumpp, G.

    2006-01-01

    In the frame of a European research project on air quality in urban agglomerations, data on ozone concentrations from 23 automated urban and suburban monitoring stations in 11 cities from seven countries were analysed and evaluated. Daily and summer mean and maximum concentrations were computed...... based on hourly mean values, and cumulative ozone exposure indices (Accumulated exposure Over a Threshold of 40 ppb (AOT40), AOT20) were calculated. The diurnal profiles showed a characteristic pattern in most city centres, with minimum values in the early morning hours, a strong rise during the morning......, by contrast, maximum values were lower and diurnal variation was much smaller. Based on ozone concentrations as well as on cumulative exposure indices, a clear north-south gradient in ozone pollution, with increasing levels from northern and northwestern sites to central and southern European sites...

  12. Validation of low-cost ozone measurement instruments suitable for use in an air-quality monitoring network

    International Nuclear Information System (INIS)

    Williams, David E; Henshaw, Geoff S; Bart, Mark; Laing, Greer; Wagner, John; Naisbitt, Simon; Salmond, Jennifer A

    2013-01-01

    This paper presents a novel low-cost instrument that uses a sensor based on conductivity changes of heated tungstic oxide, which is capable of accurately measuring ambient concentrations of ozone. A combination of temperature steps and air flow-rate steps is used to continually reset and re-zero the sensor. A two-stage calibration procedure is presented, in which a nonlinear transformation converts sensor resistance to a signal linear in ozone concentration, then a linear correlation is used to align the calibration with a reference instrument. The required calibration functions specific for the sensor, and control system for air flow rate and sensor temperature, are housed with the sensor in a compact, simple-to-exchange assembly. The instrument can be operated on solar power and uses cell phone technology to enable monitoring in remote locations. Data from field trials are presented here to demonstrate that both the accuracy and the stability of the instrument over periods of months are within a few parts-per-billion by volume. We show that common failure modes can be detected through measurement of signals available from the instrument. The combination of long-term stability, self-diagnosis, and simple, inexpensive repair means that the cost of operation and calibration of the instruments is significantly reduced in comparison with traditional reference instrumentation. These instruments enable the economical construction and operation of ozone monitoring networks of accuracy, time resolution and spatial density sufficient to resolve the local gradients that are characteristic of urban air pollution. (paper)

  13. Influence of wildfires on the variability and trend of ozone concentrations in the U.S. Intermountain West

    Science.gov (United States)

    Lu, Xiao; Zhang, Lin; Zhao, Yuanhong; Yue, Xu

    2016-04-01

    Wildfires are important sources of ozone by emitting large amounts of NOx and NMVOC, main ozone precursors at both global and regional scales. Their influences on ozone in the U.S. Intermountain West have recently received much interest because surface ozone concentrations over that region showed an increasing trend in the past two decades likely due to increasing wildfire emissions in a warming climate. Here we use the Lagrangian particle dispersion model (FLEXPART) as well as the GEOS-Chem chemical transport model to estimate wildfires' contribution on summer (June, July and August; JJA) ozone concentration variations, trends, and extremely high ozone events over the US Intermountain West for the past 22 years (1989-2010). We combine the resident time estimated from the FLEXPART 5-day backward trajectories and a high-resolution fire inventory to define a fire index representing the impact of wildfires on ozone concentration at a particular site for each day of summers 1989-2010. Over 26,000 FLEXPART back-trajectories are conducted for the whole time period and for 13 CASTNet surface monitoring sites. We build a stepwise multiple linear regression (SMLR) model of daily ozone concentrations using fire index and other meteorological variables for each site. The SMLR models explain 53% of the ozone variations (ranging from 12% to 68% for each site). We show that ozone produced from wildfires (calculated from SMLR model) are of high variability at daily scale (ranging from 0.1 ppbv to 20.7 ppbv), but are averaged to lower values of about 0.25-3.5 ppbv for summer mean. We estimate that wildfires magnify inter-annual variations of the regional mean summer ozone for about 32%, compared to the result with wildfires impact excluded from the SMLR model. Wildfire ozone enhancements increase at a rate of 0.04 ppbv per year, accouting for about 20% of the regional summer ozone trend during 1989-2010. Removing wildfires' impact would reduce 35% (46%) of the high-ozone days with

  14. Tropospheric ozone and the environment II. Effects, modeling and control

    International Nuclear Information System (INIS)

    Berglund, R.L.

    1992-01-01

    This was the sixth International Specialty Conference on ozone for the Air ampersand Waste Management Association since 1978 and the first to be held in the Southeast. Of the preceding five conferences, three were held in Houston, one in New England, and one in Los Angeles. The changing location continues to support the understanding that tropospheric ozone is a nationwide problem, requiring understanding and participation by representatives of all regions. Yet, questions such as the following continue to be raised over all aspects of the nation's efforts to control ozone. Are the existing primary and secondary National Ambient Air Quality Standards (NAAQS) for ozone the appropriate targets for the ozone control strategy, or should they be modified to more effectively accommodate new health or ecological effects information, or better fit statistical analyses of ozone modeling data? Are the modeling tools presently available adequate to predict ozone concentrations for future precursor emission trends? What ozones attainment strategy will be the best means of meeting the ozone standard? To best answer these and other questions there needs to be a continued sharing of information among researchers working on these and other questions. While answers to these questions will often be qualitative and location specific, they will help focus future research programs and assist in developing future regulatory strategies

  15. New Directions: Ozone-initiated reaction products indoors may be more harmful than ozone itself

    Science.gov (United States)

    Weschler, Charles J.

    2004-10-01

    Epidemiological studies have found associations between ozone concentrations measured at outdoor monitoring stations and certain adverse health outcomes. As a recent example, Gent et al. (2003, Journal of the American Medical Association 290, 1859-1867) have observed an association between ozone levels and respiratory symptoms as well as the use of maintenance medication by 271 asthmatic children living in Connecticut and the Springfield area of Massachusetts. In another example, Gilliland et al. (2001, Epidemiology 12, 43-54) detected an association between short-term increases in ozone levels and increased absences among 4th grade students from 12 southern California communities during the period from January to June 1996. Although children may spend a significant amount of time outdoors, especially during periods when ozone levels are elevated, they spend a much larger fraction of their time indoors. I hypothesize that exposure to the products of ozone-initiated indoor chemistry is more directly responsible for the health effects observed in the cited epidemiological studies than is exposure to outdoor ozone itself.

  16. Drivers of the tropospheric ozone budget throughout the 21st century under the medium-high climate scenario RCP 6.0

    Science.gov (United States)

    Revell, L. E.; Tummon, F.; Stenke, A.; Sukhodolov, T.; Coulon, A.; Rozanov, E.; Garny, H.; Grewe, V.; Peter, T.

    2015-05-01

    Because tropospheric ozone is both a greenhouse gas and harmful air pollutant, it is important to understand how anthropogenic activities may influence its abundance and distribution through the 21st century. Here, we present model simulations performed with the chemistry-climate model SOCOL, in which spatially disaggregated chemistry and transport tracers have been implemented in order to better understand the distribution and projected changes in tropospheric ozone. We examine the influences of ozone precursor emissions (nitrogen oxides (NOx), carbon monoxide (CO) and volatile organic compounds (VOCs)), climate change (including methane effects) and stratospheric ozone recovery on the tropospheric ozone budget, in a simulation following the climate scenario Representative Concentration Pathway (RCP) 6.0 (a medium-high, and reasonably realistic climate scenario). Changes in ozone precursor emissions have the largest effect, leading to a global-mean increase in tropospheric ozone which maximizes in the early 21st century at 23% compared to 1960. The increase is most pronounced at northern midlatitudes, due to regional emission patterns: between 1990 and 2060, northern midlatitude tropospheric ozone remains at constantly large abundances: 31% larger than in 1960. Over this 70-year period, attempts to reduce emissions in Europe and North America do not have an effect on zonally averaged northern midlatitude ozone because of increasing emissions from Asia, together with the long lifetime of ozone in the troposphere. A simulation with fixed anthropogenic ozone precursor emissions of NOx, CO and non-methane VOCs at 1960 conditions shows a 6% increase in global-mean tropospheric ozone by the end of the 21st century, with an 11 % increase at northern midlatitudes. This increase maximizes in the 2080s and is mostly caused by methane, which maximizes in the 2080s following RCP 6.0, and plays an important role in controlling ozone directly, and indirectly through its

  17. Ozone time scale decomposition and trend assessment from surface observations

    Science.gov (United States)

    Boleti, Eirini; Hueglin, Christoph; Takahama, Satoshi

    2017-04-01

    Emissions of ozone precursors have been regulated in Europe since around 1990 with control measures primarily targeting to industries and traffic. In order to understand how these measures have affected air quality, it is now important to investigate concentrations of tropospheric ozone in different types of environments, based on their NOx burden, and in different geographic regions. In this study, we analyze high quality data sets for Switzerland (NABEL network) and whole Europe (AirBase) for the last 25 years to calculate long-term trends of ozone concentrations. A sophisticated time scale decomposition method, called the Ensemble Empirical Mode Decomposition (EEMD) (Huang,1998;Wu,2009), is used for decomposition of the different time scales of the variation of ozone, namely the long-term trend, seasonal and short-term variability. This allows subtraction of the seasonal pattern of ozone from the observations and estimation of long-term changes of ozone concentrations with lower uncertainty ranges compared to typical methodologies used. We observe that, despite the implementation of regulations, for most of the measurement sites ozone daily mean values have been increasing until around mid-2000s. Afterwards, we observe a decline or a leveling off in the concentrations; certainly a late effect of limitations in ozone precursor emissions. On the other hand, the peak ozone concentrations have been decreasing for almost all regions. The evolution in the trend exhibits some differences between the different types of measurement. In addition, ozone is known to be strongly affected by meteorology. In the applied approach, some of the meteorological effects are already captured by the seasonal signal and already removed in the de-seasonalized ozone time series. For adjustment of the influence of meteorology on the higher frequency ozone variation, a statistical approach based on Generalized Additive Models (GAM) (Hastie,1990;Wood,2006), which corrects for meteorological

  18. Trends in Surface Level Ozone Observations from Human-health Relevant Metrics: Results from the Tropospheric Ozone Assessment Report (TOAR)

    Science.gov (United States)

    Fleming, Z. L.; von Schneidemesser, E.; Doherty, R. M.; Malley, C.; Cooper, O. R.; Pinto, J. P.; Colette, A.; Xu, X.; Simpson, D.; Schultz, M.; Hamad, S.; Moola, R.; Solberg, S.; Feng, Z.

    2017-12-01

    Ozone is an air pollutant formed in the atmosphere from precursor species (NOx, VOCs, CH4, CO) that is detrimental to human health and ecosystems. The global Tropospheric Ozone Assessment Report (TOAR) initiative has assembled a global database of surface ozone observations and generated ozone exposure metrics at thousands of measurement sites around the world. This talk will present results from the assessment focused on those indicators most relevant to human health. Specifically, the trends in ozone, comparing different time periods and patterns across regions and among metrics will be addressed. In addition, the fraction of population exposed to high ozone levels and how this has changed between 2000 and 2014 will also be discussed. The core time period analyzed for trends was 2000-2014, selected to include a greater number of sites in East Asia. Negative trends were most commonly observed at many US and some European sites, whereas many sites in East Asia showed positive trends, while sites in Japan showed more of a mix of positive and negative trends. More than half of the sites showed a common direction and significance in the trends for all five human-health relevant metrics. The peak ozone metrics indicate a reduction in exposure to peak levels of ozone related to photochemical episodes in Europe and the US. A considerable number of European countries and states within the US have shown a decrease in population-weighted ozone over time. The 2000-2014 results will be augmented and compared to the trend analysis for additional time periods that cover a greater number of years, but by necessity are based on fewer sites. Trends are found to be statistically significant at a larger fraction of sites with longer time series, compared to the shorter (2000-2014) time series.

  19. Improving global detection of volcanic eruptions using the Ozone Monitoring Instrument (OMI

    Directory of Open Access Journals (Sweden)

    V. J. B. Flower

    2016-11-01

    Full Text Available Volcanic eruptions pose an ever-present threat to human populations around the globe, but many active volcanoes remain poorly monitored. In regions where ground-based monitoring is present the effects of volcanic eruptions can be moderated through observational alerts to both local populations and service providers, such as air traffic control. However, in regions where volcano monitoring is limited satellite-based remote sensing provides a global data source that can be utilised to provide near-real-time identification of volcanic activity. This paper details a volcanic plume detection method capable of identifying smaller eruptions than is currently feasible, which could potentially be incorporated into automated volcanic alert systems. This method utilises daily, global observations of sulfur dioxide (SO2 by the Ozone Monitoring Instrument (OMI on NASA's Aura satellite. Following identification and classification of known volcanic eruptions in 2005–2009, the OMI SO2 data, analysed using a logistic regression analysis, permitted the correct classification of volcanic events with an overall accuracy of over 80 %. Accurate volcanic plume identification was possible when lower-tropospheric SO2 loading exceeded ∼ 400 t. The accuracy and minimal user input requirements of the developed procedure provide a basis for incorporation into automated SO2 alert systems.

  20. Trend prognosis of regional ozone maxima in 1994 using various meteorologic data

    International Nuclear Information System (INIS)

    Loibl, W.

    1995-06-01

    The purpose of this study was to develop and test a statistical method for the short-term forecast of ozone concentrations. Austrian ozone monitoring data from April to September 1994 are used to develop the forecast model. It builds upon a multiple linear regression model developed earlier which uses the temperature of the forecast day, and the ozone maxima of the previous day as variables. In this study temperature difference between previous and forecast day, and wind velocity of the forecast day were additionally taken into account. Furthermore wind direction dependent regression models were developed using subsamples of the data set devided into 8 wind direction classes. Different regression function parameters have to be applied for each of the 40 selected ozone monitoring sites to allow forecasting of regional ozone maxima throughout Austria. It was found that regression models with temperature difference and wind velocity as additional variables did not improve the results. Wind direction dependent regression models only slightly improved the results for some wind directions at several monitoring sites. Best forecast results in general were achieved by using the base regression model with the temperature of the forecast day and the ozone maxima of the previous day as variables. Ozone forecast maps were calculated by spatial interpolation of the forecasted ozone maxima of the monitoring sites. Forecast accuracy is within ± 10 ppb on 70-80 % of the observed days. Errors higher than ± 10 ppb occur mainly on days with ozone maxima of 80 ppb and more. (author)

  1. Total column ozone retrieval using INSAT-3D sounder in the tropics ...

    Indian Academy of Sciences (India)

    important for ozone estimation and lower instrument noise results in better ozone ... the Indian Space Research Organisation (ISRO) ... tivity of the sounder ozone band corresponding to .... NOAA Climate Monitoring and Diagnostics Labo-.

  2. An investigation of high ozone episodes in the City of Johannesburg

    CSIR Research Space (South Africa)

    Padayachi, YR

    2014-10-01

    Full Text Available A study of ozone monitoring data in Johannesburg highlighted that the city is frequently affected by high ozone episodes. There is limited knowledge about the chemical and meteorological drivers of these high ozone episodes in Johannesburg...

  3. Tropospheric Ozone as a Short-lived Chemical Climate Forcer

    Science.gov (United States)

    Pickering, Kenneth E.

    2012-01-01

    Tropospheric ozone is the third most important greenhouse gas according to the most recent IPCC assessment. However, tropospheric ozone is highly variable in both space and time. Ozone that is located in the vicinity of the tropopause has the greatest effect on climate forcing. Nitrogen oxides (NOx) are the most important precursors for ozone In most of the troposphere. Therefore, pollution that is lofted upward in thunderstorm updrafts or NOx produced by lightning leads to efficient ozone production in the upper troposphere, where ozone is most important climatically. Global and regional model estimates of the impact of North American pollution and lightning on ozone radiative forcing will be presented. It will be shown that in the Northern Hemisphere summer, the lightning effect on ozone radiative forcing can dominate over that of pollution, and that the radiative forcing signal from North America extends well into Europe and North Africa. An algorithm for predicting lightning flash rates and estimating lightning NOx emissions is being incorporated into the NASA GEOS-5 Chemistry and Climate Model. Changes in flash rates and emissions over an ENSO cycle and in future climates will be assessed, along with the resulting changes in upper tropospheric ozone. Other research on the production of NOx per lightning flash and its distribution in the vertical based on cloud-resolving modeling and satellite observations will be presented. Distributions of NO2 and O3 over the Middle East from the OMI instrument on NASA's Aura satellite will also be shown.

  4. Global health and economic impacts of future ozone pollution

    International Nuclear Information System (INIS)

    Selin, N E; Nam, K M; Reilly, J M; Paltsev, S; Prinn, R G; Webster, M D; Wu, S

    2009-01-01

    We assess the human health and economic impacts of projected 2000-2050 changes in ozone pollution using the MIT Emissions Prediction and Policy Analysis - Health Effects (EPPA-HE) model, in combination with results from the GEOS-Chem global tropospheric chemistry model of climate and chemistry effects of projected future emissions. We use EPPA-HE to assess the human health damages (including mortality and morbidity) caused by ozone pollution, and quantify their economic impacts in sixteen world regions. We compare the costs of ozone pollution under scenarios with 2000 and 2050 ozone precursor and greenhouse gas emissions (using the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A1B scenario). We estimate that health costs due to global ozone pollution above pre-industrial levels by 2050 will be $580 billion (year 2000$) and that mortalities from acute exposure will exceed 2 million. We find that previous methodologies underestimate costs of air pollution by more than a third because they do not take into account the long-term, compounding effects of health costs. The economic effects of emissions changes far exceed the influence of climate alone.

  5. Ozone production and hydrocarbon reactivity in Hong Kong, Southern China

    Directory of Open Access Journals (Sweden)

    J. Zhang

    2007-01-01

    Full Text Available Data obtained in Hong Kong during the Hong Kong and the Pearl River Delta (PRD Pilot Air Monitoring Study in autumn 2002 are analyzed to unravel the relationship between ground-level ozone (O3, pollution precursors, and cross-border transport. Ten ozone episodes, during which the hourly O3 concentration exceeded 100 ppbv in 9 cases and 90 ppbv in one case, are subject to detailed analysis, including one case with hourly O3 of 203 ppbv, which is the highest concentration on record to date in Hong Kong. Combined with high-resolution back trajectories, dCO/dNOy (the ratio of enhancement of CO concentration above background to that of NOy is used to define whether O3 is locally or regionally produced. Five out of the ten Hong Kong O3-episodes studied show a "pollution signature" that is indicative of impact from Guangdong Province. Examination of speciated volatile organic compounds (VOCs shows that the reactivity of VOCs is dominated by anthropogenic VOCs, of which the reactive aromatics dominate, in particular xylenes and toluene. Calculations using a photochemical box model indicate that between 50–100% of the O3 increase observed in Hong Kong during the O3 episodes can be explained by photochemical generation within the Hong Kong area, provided that nitrous acid (HONO is present at the concentrations derived from this study. An Observation-Based Model (OBM is used to calculate the sensitivity of the O3 production to changes in the concentrations of the precursor compounds. Generally the production of O3 throughout much of the Hong Kong area is limited by VOCs, while high nitric oxide (NO concentrations suppress O3 concentration.

  6. Spatial and temporal variability of tropospheric ozone over Europe

    Energy Technology Data Exchange (ETDEWEB)

    Scheel, H.E.; Sladkovic, R. [Fraunhofer Inst. (IFU), Garmisch-Partenkirchen (Germany); Ancellet, G. [Universite Paris 6 (France). Service d`Aeronomie du CNRS; Areskoug, H. [Air Pollution Lab., Inst. of Applied Environmental Research, Stockholm Univ. (Sweden); Beck, J.; Waal, L. de [RIVM-LLO, Bilthoven (Netherlands); Boesenberg, J.; Grabbe, G. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Muer, D. de [Meteorological Inst. of Belgium (KMI), Brussels (Belgium); Dutot, A.L.; Etienne, A.; Perros, P.; Toupance, G. [Universite Paris XII-Creteil (France). Lab. de Physico-Chimie de l`Environment; Egelov, A.H.; Granby, K. [National Environmental Research Inst., Roskilde (Denmark); Esser, P.; Roemer, M. [IMW-TNO, Delft (Netherlands); Ferenczi, Z.; Haszpra, L. [Institute for Atmospheric Physics, Budapest (Hungary); Geiss, H.; Smit, H. [Forschungszentrum Juelich (Germany). Inst. fuer Chemie und Dynamik der Geosphaere (ICG-2); Gomiscek, B. [Ljubljana Univ. (Slovenia). Faculty of Chemistry and Chemical Technology; Kezele, N.; Klasinc, L. [Institut Rudjer Boskovic, Zagreb (Croatia); Laurila, T. [Finnish Meteorological Inst., Helsinki (Finland). Dept. of Air Quality; Lindskog, A.; Mowrer, J. [Swedish Environmental Research Inst. (IVL), Goeteborg (Sweden); Nielsen, T. [Risoe National Laboratory, Roskilde (Denmark); Schmitt, R. [Meteorologie Consult GmbH, Glashuetten (Germany); Simmonds, P. [International Science Consultants, Ringwood (United Kingdom); Solberg, S. [NILU, Kjeller (Norway); Varotsos, C. [Athens Univ. (Greece); TOR Task Group 1

    1997-12-31

    The first section is concerned with the characteristics of the TOR-measurement sites and the data used. It describes the methodologies employed for the selection of data in order to obtain representative ozone concentrations with minimum bias caused by the individual location. The question of representativeness of the O{sub 3} concentrations at the TOR sites was given special attention, since it is a crucial point for all conclusions drawn from the observations. Therefore several studies were focused on this issue. The further sections of the report deal with results on the spatial and seasonal variations of ozone concentrations over Europe. Results obtained from in-situ measurements in the boundary layer/lower free troposphere and from vertical soundings in the free troposphere are regarded separately. Finally, trend estimates are presented for ozone as well as for some of its precursors. (orig./KW)

  7. Spatial and temporal variability of tropospheric ozone over Europe

    Energy Technology Data Exchange (ETDEWEB)

    Scheel, H E; Sladkovic, R [Fraunhofer Inst. (IFU), Garmisch-Partenkirchen (Germany); Ancellet, G [Universite Paris 6 (France). Service d` Aeronomie du CNRS; Areskoug, H [Air Pollution Lab., Inst. of Applied Environmental Research, Stockholm Univ. (Sweden); Beck, J; Waal, L de [RIVM-LLO, Bilthoven (Netherlands); Boesenberg, J; Grabbe, G [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Muer, D de [Meteorological Inst. of Belgium (KMI), Brussels (Belgium); Dutot, A L; Etienne, A; Perros, P; Toupance, G [Universite Paris XII-Creteil (France). Lab. de Physico-Chimie de l` Environment; Egelov, A H; Granby, K [National Environmental Research Inst., Roskilde (Denmark); Esser, P; Roemer, M [IMW-TNO, Delft (Netherlands); Ferenczi, Z; Haszpra, L [Institute for Atmospheric Physics, Budapest (Hungary); Geiss, H; Smit, H [Forschungszentrum Juelich (Germany). Inst. fuer Chemie und Dynamik der Geosphaere (ICG-2); Gomiscek, B [Ljubljana Univ. (Slovenia). Faculty of Chemistry and Chemical Technology; Kezele, N; Klasinc, L [Institut Rudjer Boskovic, Zagreb (Croatia); Laurila, T [Finnish Meteorological Inst., Helsinki (Finland). Dept. of Air Quality; Lindskog, A; Mowrer, J [Swedish Environmental Research Inst. (IVL), Goeteborg (Sweden); Nielsen, T [Risoe National Laboratory, Roskilde (Denmark); Schmitt, R [Meteorologie Consult GmbH, Glashuetten (Germany); Simmonds, P [International Science Consultants, Ringwood (United Kingdom); Solberg, S [NILU, Kjeller (Norway); Varotsos, C [Athens Univ. (Greece); TOR Task Group 1

    1998-12-31

    The first section is concerned with the characteristics of the TOR-measurement sites and the data used. It describes the methodologies employed for the selection of data in order to obtain representative ozone concentrations with minimum bias caused by the individual location. The question of representativeness of the O{sub 3} concentrations at the TOR sites was given special attention, since it is a crucial point for all conclusions drawn from the observations. Therefore several studies were focused on this issue. The further sections of the report deal with results on the spatial and seasonal variations of ozone concentrations over Europe. Results obtained from in-situ measurements in the boundary layer/lower free troposphere and from vertical soundings in the free troposphere are regarded separately. Finally, trend estimates are presented for ozone as well as for some of its precursors. (orig./KW)

  8. Temporal and Spatial Variation in, and Population Exposure to, Summertime Ground-Level Ozone in Beijing.

    Science.gov (United States)

    Zhao, Hui; Zheng, Youfei; Li, Ting; Wei, Li; Guan, Qing

    2018-03-29

    Ground-level ozone pollution in Beijing has been causing concern among the public due to the risks posed to human health. This study analyzed the temporal and spatial distribution of, and investigated population exposure to, ground-level ozone. We analyzed hourly ground-level ozone data from 35 ambient air quality monitoring sites, including urban, suburban, background, and traffic monitoring sites, during the summer in Beijing from 2014 to 2017. The results showed that the four-year mean ozone concentrations for urban, suburban, background, and traffic monitoring sites were 95.1, 99.8, 95.9, and 74.2 μg/m³, respectively. A total of 44, 43, 45, and 43 days exceeded the Chinese National Ambient Air Quality Standards (NAAQS) threshold for ground-level ozone in 2014, 2015, 2016, and 2017, respectively. The mean ozone concentration was higher in suburban sites than in urban sites, and the traffic monitoring sites had the lowest concentration. The diurnal variation in ground-level ozone concentration at the four types of monitoring sites displayed a single-peak curve. The peak and valley values occurred at 3:00-4:00 p.m. and 7:00 a.m., respectively. Spatially, ground-level ozone concentrations decreased in gradient from the north to the south. Population exposure levels were calculated based on ground-level ozone concentrations and population data. Approximately 50.38%, 44.85%, and 48.49% of the total population of Beijing were exposed to ground-level ozone concentrations exceeding the Chinese NAAQS threshold in 2014, 2015, and 2016, respectively.

  9. Temporal and Spatial Variation in, and Population Exposure to, Summertime Ground-Level Ozone in Beijing

    Science.gov (United States)

    Zheng, Youfei; Li, Ting; Wei, Li; Guan, Qing

    2018-01-01

    Ground-level ozone pollution in Beijing has been causing concern among the public due to the risks posed to human health. This study analyzed the temporal and spatial distribution of, and investigated population exposure to, ground-level ozone. We analyzed hourly ground-level ozone data from 35 ambient air quality monitoring sites, including urban, suburban, background, and traffic monitoring sites, during the summer in Beijing from 2014 to 2017. The results showed that the four-year mean ozone concentrations for urban, suburban, background, and traffic monitoring sites were 95.1, 99.8, 95.9, and 74.2 μg/m3, respectively. A total of 44, 43, 45, and 43 days exceeded the Chinese National Ambient Air Quality Standards (NAAQS) threshold for ground-level ozone in 2014, 2015, 2016, and 2017, respectively. The mean ozone concentration was higher in suburban sites than in urban sites, and the traffic monitoring sites had the lowest concentration. The diurnal variation in ground-level ozone concentration at the four types of monitoring sites displayed a single-peak curve. The peak and valley values occurred at 3:00–4:00 p.m. and 7:00 a.m., respectively. Spatially, ground-level ozone concentrations decreased in gradient from the north to the south. Population exposure levels were calculated based on ground-level ozone concentrations and population data. Approximately 50.38%, 44.85%, and 48.49% of the total population of Beijing were exposed to ground-level ozone concentrations exceeding the Chinese NAAQS threshold in 2014, 2015, and 2016, respectively. PMID:29596366

  10. Temporal and Spatial Variation in, and Population Exposure to, Summertime Ground-Level Ozone in Beijing

    Directory of Open Access Journals (Sweden)

    Hui Zhao

    2018-03-01

    Full Text Available Ground-level ozone pollution in Beijing has been causing concern among the public due to the risks posed to human health. This study analyzed the temporal and spatial distribution of, and investigated population exposure to, ground-level ozone. We analyzed hourly ground-level ozone data from 35 ambient air quality monitoring sites, including urban, suburban, background, and traffic monitoring sites, during the summer in Beijing from 2014 to 2017. The results showed that the four-year mean ozone concentrations for urban, suburban, background, and traffic monitoring sites were 95.1, 99.8, 95.9, and 74.2 μg/m3, respectively. A total of 44, 43, 45, and 43 days exceeded the Chinese National Ambient Air Quality Standards (NAAQS threshold for ground-level ozone in 2014, 2015, 2016, and 2017, respectively. The mean ozone concentration was higher in suburban sites than in urban sites, and the traffic monitoring sites had the lowest concentration. The diurnal variation in ground-level ozone concentration at the four types of monitoring sites displayed a single-peak curve. The peak and valley values occurred at 3:00–4:00 p.m. and 7:00 a.m., respectively. Spatially, ground-level ozone concentrations decreased in gradient from the north to the south. Population exposure levels were calculated based on ground-level ozone concentrations and population data. Approximately 50.38%, 44.85%, and 48.49% of the total population of Beijing were exposed to ground-level ozone concentrations exceeding the Chinese NAAQS threshold in 2014, 2015, and 2016, respectively.

  11. Quantifying Ozone Production throughout the Boundary Layer from High Frequency Tethered Profile Measurements during a High Ozone Episode in the Uinta Basin, Utah

    Science.gov (United States)

    Sterling, C. W.; Johnson, B.; Schnell, R. C.; Oltmans, S. J.; Cullis, P.; Hall, E. G.; Jordan, A. F.; Windell, J.; McClure-Begley, A.; Helmig, D.; Petron, G.

    2015-12-01

    During the Uinta Basin Winter Ozone Study (UBWOS) in Jan - Feb 2013, 735 tethered ozonesonde profiles were obtained at 3 sites including during high wintertime photochemical ozone production events that regularly exceeded 125 ppb. High resolution profiles of ozone and temperature with altitude, measured during daylight hours, showed the development of approximately week long high ozone episodes building from background levels of ~40 ppb to >150 ppb. The topography of the basin combined with a strong temperature inversion trapped oil and gas production effluents in the basin and the snow covered surface amplified the sun's radiation driving the photochemical ozone production at rates up to 13 ppb/hour in a cold layer capped at 1600-1700 meters above sea level. Beginning in mid-morning, ozone mixing ratios throughout the cold layer increased until late afternoon. Ozone mixing ratios were generally constant with height indicating that ozone production was nearly uniform throughout the depth of the cold pool. Although there was strong diurnal variation, ozone mixing ratios increased during the day more than decreased during the night, resulting in elevated levels the next morning; an indication that nighttime loss processes did not compensate for daytime production. Even though the 3 tethersonde sites were at elevations differing by as much as 140 m, the top of the high ozone layer was nearly uniform in altitude at the 3 locations. Mobile van surface ozone measurements across the basin confirmed this capped structure of the ozone layer; the vehicle drove out of high ozone mixing ratios at an elevation of ~1900 meters above sea level, above which free tropospheric ozone mixing ratios of ~50 ppb were measured. Exhaust plumes from a coal-fired power plant in the eastern portion of the basin were intercepted by the tethersondes. The structure of the profiles clearly showed that effluents in the plumes were not mixed downward and thus did not contribute precursor nitrogen

  12. Vertical ozone transport in the Alps (VOTALP): the valley experiment 1996

    Energy Technology Data Exchange (ETDEWEB)

    Furger, M; Dommen, J; Graber, W K; Prevot, A; Poggio, L; Andreani, S; Keller, J; Portmann, W; Buerki, D; Erne, R; Richter, R; Tinguely, M [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    The EU project VOTALP started its valley campaign in the summer of 1996 in the Mesolcina valley. The influence of thermal circulations on ozone concentrations and on the exchange of ozone and its photochemical precursors between the valley atmosphere and the free troposphere above was the main focus of the study. PSI has participated with various measurement systems (conventional meteorological surface stations, radiosondes, scidar/DOAS systems, chemical analysers). An overview of PSI`s activities in the field campaign is given, and some preliminary results are presented. (author) 1 fig., 2 tabs., 2 refs.

  13. OZONE PRECURSORS, SOURCE REGIONS, AND O(3) FORMATION DURING THE TEXAQS 2000 STUDY

    International Nuclear Information System (INIS)

    DAUM, P.H.; KLEINMAN, L.I.; BRECHTEL, F.; LEE, Y.N.; NUNNERMACKER, L.J.; SPRINGSTON, S.R.; WEINSTEIN-LLOYD, J.

    2001-01-01

    The DOE G-1 aircraft made flights on 14 days during the TexAQS 2000 study. On 7 of those days, the aircraft encountered highly localized plumes exhibiting O(sub 3) concentrations in excess of 150 ppb; on some days, peak O(sub 3) concentrations were in excess of 200 ppb. These ozone plumes were rapidly formed with an efficiency (O(sub 3) per NO(sub x) molecule consumed) much higher (7-20) than observed in other urban areas (3-4), and were frequently associated with high concentrations ( and gt;20 ppb) of secondary hydrocarbon species such as formaldehyde. Back trajectory analysis showed that the plumes were invariably associated with emissions from one or more of the large industrial complexes clustered about the Houston Ship Channel and Galveston Bay. Very high hydrocarbon reactivities were found in the vicinity of these facilities during morning flights. These hydrocarbon reactivities, in combination with local NO(sub x) emissions, were large enough to support instantaneous O(sub 3) production rates as high as 200 ppb/h. It is hypothesized that the combination of nitrogen oxides and hydrocarbon emissions emanating from this complex of industries provided a potent mixture of chemicals that caused the rapid formation of very high concentrations of ozone which, depending on the prevailing meteorology, could cause exceedance of the NAAQS ozone standard anywhere in the Houston metropolitan area

  14. Removal of soluble microbial products as the precursors of disinfection by-products in drinking water supplies.

    Science.gov (United States)

    Liu, Jin-Lin; Li, Xiao-Yan

    2015-01-01

    Water pollution worsens the problem of disinfection by-products (DBPs) in drinking water supply. Biodegradation of wastewater organics produces soluble microbial products (SMPs), which can be important DBP precursors. In this laboratory study, a number of enhanced water treatment methods for DBP control, including enhanced coagulation, ozonation, and activated carbon adsorption, were evaluated for their effectiveness in treating SMP-containing water for the DBP reduction purpose. The results show that enhanced coagulation with alum could remove SMPs only marginally and decrease the DBP formation potential (DBPFP) of the water by less than 20%. Although ozone could cause destruction of SMPs in water, the overall DBPFP of the water did not decrease but increased after ozonation. In contrast, adsorption by granular activated carbon could remove the SMP organics from water by more than 60% and reduce the DBPFP by more than 70%. It is apparent that enhanced coagulation and ozonation are not suitable for the removal of SMPs as DBP precursors from polluted water, although enhanced coagulation has been commonly used to reduce the DBP formation caused by natural organic matter. In comparison, activated carbon adsorption is shown as a more effective means to remove the SMP content from water and hence to control the wastewater-derived DBP problem in water supply.

  15. Products of BVOC oxidation: ozone and organic aerosols

    Science.gov (United States)

    Wildt, Jürgen; Andres, Stefanie; Carriero, Giulia; Ehn, Mikael; Fares, Silvano; Hoffmann, Thorsten; Hacker, Lina; Kiendler-Scharr, Astrid; Kleist, Einhard; Paoletti, Elena; Pullinen, Iida; Rohrer, Franz; Rudich, Yinon; Springer, Monika; Tillmann, Ralf; Wahner, Andreas; Wu, Cheng; Mentel, Thomas

    2015-04-01

    Biogenic Volatile Organic Compounds (BVOC) are important precursors in photochemical O3 and secondary organic aerosol (SOA) formation. We conducted a series of laboratory experiments with OH-induced oxidation of monoterpenes to elucidate pathways and efficiencies of O3 and SOA formation. At high NOx conditions ([BVOC] / [NOx] monoterpene mixes emitted from different plant species we observed increasing ozone formation with increasing [NOX]. Between 2 and 3 O3-molecules were formed from 1 monoterpene when ozone formation was BVOC limited. Under such high NOX conditions, new particle formation was suppressed. Increasing [BVOC] / [NOX] ratios caused increasing efficiency of new particle formation indicating that peroxy radicals are the key intermediates in both, photochemical ozone- and new particle formation. The classical chemistry of peroxy radicals is well established (e.g. Master Chemical Mechanism). Peroxy radicals are produced by addition of molecular oxygen to the alkyl radical formed after OH attack at the BVOC. They either react with NO which leads to ozone formation or they react with other peroxy radicals and form chemically stable products (hydroperoxides, alkoholes and ketones). Much less knowledge exists on such reactions for Highly Oxidized Peroxy Radicals, (HOPR). Such HOPR were observed during ozonolysis of several volatiles and, in case of monoterpenes as precursors, they can contain more than 12 Oxygen atoms (Mentel et al., 2015). Although the OH-initiated formation of HOPR is yet not fully understood, their basic gas phase reactions seem to follow classical photochemical rules. In reactions with NO they can act as precursor for O3 and in reactions with other HOPR or with classical less oxidized peroxy radicals they can form highly oxidized stable products and alkoxy radicals. In addition, HOPR-HOPR reactions lead to the formation of dimers that, in case of monoterpenes as reactants, consist of a skeleton with 20 carbon atoms. These dimers seem to

  16. Ozone zonal asymmetry and planetary wave characterization during Antarctic spring

    Directory of Open Access Journals (Sweden)

    I. Ialongo

    2012-03-01

    Full Text Available A large zonal asymmetry of ozone has been observed over Antarctica during winter-spring, when the ozone hole develops. It is caused by a planetary wave-driven displacement of the polar vortex. The total ozone data by OMI (Ozone Monitoring Instrument and the ozone profiles by MLS (Microwave Limb Sounder and GOMOS (Global Ozone Monitoring by Occultation of Stars were analysed to characterize the ozone zonal asymmetry and the wave activity during Antarctic spring. Both total ozone and profile data have shown a persistent zonal asymmetry over the last years, which is usually observed from September to mid-December. The largest amplitudes of planetary waves at 65° S (the perturbations can achieve up to 50% of zonal mean values is observed in October. The wave activity is dominated by the quasi-stationary wave 1 component, while the wave 2 is mainly an eastward travelling wave. Wave numbers 1 and 2 generally explain more than the 90% of the ozone longitudinal variations. Both GOMOS and MLS ozone profile data show that ozone zonal asymmetry covers the whole stratosphere and extends up to the altitudes of 60–65 km. The wave amplitudes in ozone mixing ratio decay with altitude, with maxima (up to 50% below 30 km.

    The characterization of the ozone zonal asymmetry has become important in the climate research. The inclusion of the polar zonal asymmetry in the climate models is essential for an accurate estimation of the future temperature trends. This information might also be important for retrieval algorithms that rely on ozone a priori information.

  17. Trend prognosis of regional ozone maxima in 1994 using various meteorologic data: appendix

    International Nuclear Information System (INIS)

    Loibl, W.

    1995-06-01

    The purpose of this study was to develop and test a statistical method for the short-term forecast of ozone concentrations. Austrian ozone monitoring data from April to September 1994 are used to develop the forecast model. It builds upon a multiple linear regression model developed earlier which uses the temperature of the forecast day, and the ozone maxima of the previous day as variables. In this study temperature difference between previous and forecast day, and wind velocity of the forecast day were additionally taken into account. Furthermore wind direction dependent regression models were developed using subsamples of the data set devided into 8 wind direction classes. Different regression function parameters have to be applied for each of the 40 selected ozone monitoring sites to allow forecasting of regional ozone maxima throughout Austria. It was found that regression models with temperature difference and wind velocity as additional variables did not improve the results. Wind direction dependent regression models only slightly improved the results for some wind directions at several monitoring sites. Best forecast results in general were achieved by using the base regression model with the temperature of the forecast day and the ozone maxima of the previous day as variables. Ozone forecast maps were calculated by spatial interpolation of the forecasted ozone maxima of the monitoring sites. Forecast accuracy is within ± 10 ppb on 70-80 % of the observed days. Errors higher than ± 10 ppb occur mainly on days with ozone maxima of 80 ppb and more. (author)

  18. Table - Impacts of the Proposed Transport Rule on Counties with Monitors Projected to have Ozone and/or Fine Particle Air Quality Problems

    Science.gov (United States)

    This table shows the impacts of the proposed Transport Rule on Counties with Monitors Projected to have Ozone and/or Fine Particle Air Quality Problems, both with and without the Cross-State Air Pollution Rule.

  19. Tropospheric Ozone Change from 1980 to 2010 Dominated by Equatorward Redistribution of Emissions

    Science.gov (United States)

    Zhang, Yuqiang; Cooper, Owen R.; Gaudel, Audrey; Thompson, Anne M.; Nedelec, Philippe; Ogino, Shin-Ya; West, J. Jason

    2016-01-01

    Ozone is an important air pollutant at the surface, and the third most important anthropogenic greenhouse gas in the troposphere. Since 1980, anthropogenic emissions of ozone precursors methane, non-methane volatile organic compounds, carbon monoxide and nitrogen oxides (NOx) have shifted from developed to developing regions. Emissions have thereby been redistributed equatorwards, where they are expected to have a stronger effect on the tropospheric ozone burden due to greater convection, reaction rates and NOx sensitivity. Here we use a global chemical transport model to simulate changes in tropospheric ozone concentrations from 1980 to 2010, and to separate the influences of changes in the spatial distribution of global anthropogenic emissions of short-lived pollutants, the magnitude of these emissions, and the global atmospheric methane concentration. We estimate that the increase in ozone burden due to the spatial distribution change slightly exceeds the combined influences of the increased emission magnitude and global methane. Emission increases in Southeast, East and South Asia may be most important for the ozone change, supported by an analysis of statistically significant increases in observed ozone above these regions. The spatial distribution of emissions dominates global tropospheric ozone, suggesting that the future ozone burden will be determined mainly by emissions from low latitudes.

  20. Impact of climate variability on tropospheric ozone

    International Nuclear Information System (INIS)

    Grewe, Volker

    2007-01-01

    A simulation with the climate-chemistry model (CCM) E39/C is presented, which covers both the troposphere and stratosphere dynamics and chemistry during the period 1960 to 1999. Although the CCM, by its nature, is not exactly representing observed day-by-day meteorology, there is an overall model's tendency to correctly reproduce the variability pattern due to an inclusion of realistic external forcings, like observed sea surface temperatures (e.g. El Nino), major volcanic eruption, solar cycle, concentrations of greenhouse gases, and Quasi-Biennial Oscillation. Additionally, climate-chemistry interactions are included, like the impact of ozone, methane, and other species on radiation and dynamics, and the impact of dynamics on emissions (lightning). However, a number of important feedbacks are not yet included (e.g. feedbacks related to biogenic emissions and emissions due to biomass burning). The results show a good representation of the evolution of the stratospheric ozone layer, including the ozone hole, which plays an important role for the simulation of natural variability of tropospheric ozone. Anthropogenic NO x emissions are included with a step-wise linear trend for each sector, but no interannual variability is included. The application of a number of diagnostics (e.g. marked ozone tracers) allows the separation of the impact of various processes/emissions on tropospheric ozone and shows that the simulated Northern Hemisphere tropospheric ozone budget is not only dominated by nitrogen oxide emissions and other ozone pre-cursors, but also by changes of the stratospheric ozone budget and its flux into the troposphere, which tends to reduce the simulated positive trend in tropospheric ozone due to emissions from industry and traffic during the late 80s and early 90s. For tropical regions the variability in ozone is dominated by variability in lightning (related to ENSO) and stratosphere-troposphere exchange (related to Northern Hemisphere Stratospheric

  1. Importance of Ship Emissions to Local Summertime Ozone Production in the Mediterranean Marine Boundary Layer: A Modeling Study

    OpenAIRE

    Christian N. Gencarelli; Ian M. Hedgecock; Francesca Sprovieri; Gregor J. Schürmann; Nicola Pirrone

    2014-01-01

    Ozone concentrations in the Mediterranean area regularly exceed the maximum levels set by the EU Air Quality Directive, 2008/50/CE, a maximum 8-h mean of 120 μg·m-3, in the summer, with consequences for both human health and agriculture. There are a number of reasons for this: the particular geographical and meteorological conditions in the Mediterranean play a part, as do anthropogenic ozone precursor emissions from around the Mediterranean and continental Europe. Ozone concentrations measur...

  2. Fast Flow Cavity Enhanced Ozone Monitor, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Naturally occurring in the stratosphere, ozone plays a significant role in many atmospheric reactions, cloud formation, and is the key player in shielding harmful UV...

  3. Role of ozone and granular activated carbon in the removal of mutagenic compounds.

    Science.gov (United States)

    Bourbigot, M M; Hascoet, M C; Levi, Y; Erb, F; Pommery, N

    1986-01-01

    The identification of certain organic compounds in drinking water has led water treatment specialists to be increasingly concerned about the eventual risks of such pollutants to the health of consumers. Our experiments focused on the role of ozone and granular activated carbon in removing mutagenic compounds and precursors that become toxic after chlorination. We found that if a sufficient dose of ozone is applied, its use does not lead to the creation of mutagenic compounds in drinking water and can even eliminate the initial mutagenicity of the water. The formation of new mutagenic compounds seems to be induced by ozonation that is too weak, although these mutagens can be removed by GAC filtration. Ozone used with activated carbon can be one of the best means for eliminating the compounds contributing to the mutagenicity of water. A combined treatment of ozone and activated carbon also decreases the chlorine consumption of the treated water and consequently reduces the formation of chlorinated organic compounds. PMID:3816720

  4. Coincident Observations of Surface Ozone and NMVOCs over Abu Dhabi

    Science.gov (United States)

    Abbasi, Naveed; Majeed, Tariq; Iqbal, Mazhar; Tarasick, David; Davies, Jonathan; Riemer, Daniel; Apel, Eric

    2016-07-01

    The vertical profiles of ozone are measured coincidently with non-methane volatile organic compounds (NMVOCs) at the meteorological site located at the Abu Dhabi international airport (latitude 24.45N; longitude 54.22E) during the years 2012 - 2014. Some of the profiles show elevated surface ozone >95 ppbv during the winter months (December, January and February). The ground-level NMVOCs obtained from the gas chromatography-flame ionization detection/mass spectrometry system also show elevated values of acetylene, ethane, propane, butane, pentane, benzene, and toluene. NMVOCs and ozone abundances in other seasons are much lower than the values in winter season. NMVOCs are emitted from an extensive number of sources in urban environments including fuel production, distribution, and consumption, and serve as precursor of ozone. Transport sources contribute a substantial portion of the NMVOC burden to the urban atmosphere in developed regions. Abu Dhabi is located at the edge of the Arabian Gulf and is highly affected by emissions from petrochemical industries in the neighboring Gulf region. The preliminary results indicate that wintertime enhancement in ozone is associated with large values of NMVOCs at Abu Dhabi. The domestic production of surface ozone is estimated from the combination of oxygen recombination and NMVOCs and compared with the data. It is estimated that about 40-50% of ozone in Abu Dhabi is transported from the neighbouring petrochemical industries. We will present ozone sounding and NMVOCs data and our model estimates of surface ozone, including a discussion on the high levels of the tropospheric ozone responsible for contaminating the air quality in the UAE. This work is supported by National Research Foundation, UAE.

  5. Towards an Integrated Assessment Model for Tropospheric Ozone-Emission Inventories, Scenarios and Emission-control Options

    OpenAIRE

    Olsthoorn, X.

    1994-01-01

    IIASA intends to extend its RAINS model for addressing the issue of transboundary ozone air pollution. This requires the development of a VOC-emissions module, VOCs being precursors in ozone formation. The module should contain a Europe-wide emission inventory, a submodule for developing emission scenarios and a database of measures for VOC-emission control, including data about control effectiveness and control costs. It is recommended to use the forthcoming CORINAIR90 inventory for construc...

  6. Ozone air pollution in the Ukrainian Carpathian Mountains and Kiev region

    Science.gov (United States)

    Oleg Blum; Andrzej Bytnerowicz; William Manning; Ludmila Popovicheva

    1998-01-01

    Ambient concentrations of ozone (O3) were measured at five highland forest locations in the Ukrainian Carpathians and in two lowland locations in the Kiev region during August to September 1995 by using O3 passive samplers. The ozone passive samplers were calibrated against a Thermo Environmental Model 49 ozone monitor...

  7. Compact, Rugged and Low-Cost Atmospheric Ozone DIAL Transmitter, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Real-time, high-frequency measurements of atmospheric ozone are becoming increasingly important to understand the impact of ozone towards climate change, to monitor...

  8. A dynamic dilution system-based evaluation of the procedure adopted for determining ozone precursor volatile compounds.

    Science.gov (United States)

    Palluau, Fabienne; Mirabel, Philippe; Millet, Maurice

    2005-02-01

    A dynamic dilution system was created to evaluate the performance and the reliability of ozone precursor volatile organic compound (VOC) sampling ("TO-Can" canisters) and analysis (thermal desorption/gas chromatography/flame ionisation detection) techniques used by the "Laboratoire Interregional de Chimie du Grand Est (LIC)". Different atmospheres of VOCs were generated at concentrations between 0.8 and 25 ppb, with temperatures of 0, 10, 20 and 30 degrees C, and with relative humidities of 0, 30, 50, 70 and 90%. These conditions are generally representative of those commonly observed in ambient air in the eastern France. This dynamic dilution allows the simulation of a wide range of scenarios (concentrations, temperatures and relative humidities). After assessing the capacity and performance of the system, it was applied in order to evaluate the recoveries and stabilities of VOCs from canisters used for the collection and analysis of two mixtures of VOCs. The first mixture contained six alkanes (ethane, propane, butane, pentane, hexane and heptane), and the second contained five alkenes (ethene, propene, butene, 1-pentene and 1-hexene), five aromatics (benzene, toluene, ethylbenzene, m-xylene and o-xylene), acetylene, and 1,3-butadiene. No significant losses of alkanes from the canisters were observed after 21 days of storage, and good recoveries of alkanes from the canisters (>80%) were obtained regardless of the concentration, the temperature and the relative humidity. However, losses of certain aromatics were noted at low relative humidity.

  9. Sensitivity analysis of ground level ozone in India using WRF-CMAQ models

    NARCIS (Netherlands)

    Sharma, Sumit; Chatani, Satoru; Mahtta, Richa; Goel, Anju; Kumar, Atul

    2016-01-01

    Ground level ozone is emerging as a pollutant of concern in India. Limited surface monitoring data reveals that ozone concentrations are well above the prescribed national standards. This study aims to simulate the regional and urban scale ozone concentrations in India using WRF-CMAQ models.

  10. Influence of local meteorology and NO2 conditions on ground-level ozone concentrations in the eastern part of Texas, USA

    OpenAIRE

    Gorai, A. K.; Tuluri, F.; Tchounwou, P. B.; Ambinakudige, S.

    2015-01-01

    The influence of local climatic factors on ground-level ozone concentrations is an area of increasing interest to air quality management in regards to future climate change. This study presents an analysis on the role of temperature, wind speed, wind direction, and NO2 level on ground-level ozone concentrations over the region of Eastern Texas, USA. Ozone concentrations at the ground level depend on the formation and dispersion processes. Formation process mainly depends on the precursor sour...

  11. Characteristics of surface ozone in Agra, a sub-urban site in Indo ...

    Indian Academy of Sciences (India)

    Nidhi Verma

    2018-04-09

    Apr 9, 2018 ... In the present study, measurements of surface ozone (O3) and its precursors (NO and NO2) were carried out at a ...... from road traffic in Great Britain; Atmos. Environ. 54 ... L, Doddridge B G and Holben B N 1997 The impact of.

  12. Ozone-Depleting Gases in the Atmosphere: Results From 28 Years of Measurements by the NOAA Climate Monitoring and Diagnostics Laboratory (CMDL)

    Science.gov (United States)

    Hurst, D. F.; Elkins, J. W.; Montzka, S. A.; Butler, J. H.; Dutton, G. S.; Hall, B. D.; Mondeel, D. J.; Moore, F. L.; Nance, J. D.; Romashkin, P. A.; Thompson, T. M.

    2005-12-01

    Back in 1978, NOAA/CMDL initiated the weekly filling of flasks at CMDL observatories in Alaska, Hawaii, American Samoa, and Antarctica for analyses of CFC-11, CFC-12 and N2O in the home laboratory. A decade later, each observatory was outfitted with an automated gas chromatograph to make routine, in situ measurements of these three source gases plus methyl chloroform and carbon tetrachloride. Both measurement programs are ongoing, having expanded over the years to include methyl halides and substitutes for regulated halocarbons, to presently account for 95% of the total burden of long-lived Cl and Br believed to enter the stratosphere. These long-term monitoring data have been assimilated into temporal records of the global tropospheric burdens of ozone-depleting chlorine and bromine which are critical input to models that predict future trends in stratospheric ozone. Other information pivotal to ozone projections, such as the atmospheric lifetimes of source gases, stratospheric entry values for total chlorine and total bromine, and identification of the stratospheric sink regions for long-lived source gases, has been gained from in situ measurements by NOAA/CMDL instruments aboard NASA high-altitude aircraft (ER-2 and WB-57) and balloons since 1991. Though CMDL's routine monitoring activities provide important historical records of halogenated source gases in the atmosphere, significant inaccuracies in ozone projections may propagate from the uncertain estimates of impending emissions of ozone-depleting gases. Scenarios of future halocarbon emissions require substantial assumptions about past and pending compliance with the Montreal Protocol, and the sizes and release rates of existing global reservoirs (banks) of halocarbons. Recent work by CMDL has focused on quantifying halocarbon bank emission rates in Russia, the USA, and Canada through geographically extensive measurements aboard trains and low-altitude aircraft. The USA and Canada results indicate that

  13. Using satellite data to guide emission control strategies for surface ozone pollution

    Science.gov (United States)

    Jin, X.; Fiore, A. M.

    2017-12-01

    Surface ozone (O3) has adverse effects on public health, agriculture and ecosystems. As a secondary pollutant, ozone is not emitted directly. Ozone forms from two classes of precursors: NOx and VOCs. We use satellite observations of formaldehyde (a marker of VOCs) and NO2 (a marker of NOx) to identify areas which would benefit more from reducing NOx emissions (NOx-limited) versus areas where reducing VOC emissions would lead to lower ozone (VOC-limited). We use a global chemical transport model (GEOS-Chem) to develop a set of threshold values that separate the NOx-limited and VOC-limited conditions. Combining these threshold values with a decadal record of satellite observations, we find that U.S. cities (e.g. New York, Chicago) have shifted from VOC-limited to NOx-limited ozone production regimes in the warm season. This transition reflects the NOx emission controls implemented over the past decade. Increasing NOx sensitivity implies that regional NOx emission control programs will improve O3 air quality more now than it would have a decade ago.

  14. Simultaneous assimilation of ozone profiles from multiple UV-VIS satellite instruments

    Science.gov (United States)

    van Peet, Jacob C. A.; van der A, Ronald J.; Kelder, Hennie M.; Levelt, Pieternel F.

    2018-02-01

    A three-dimensional global ozone distribution has been derived from assimilation of ozone profiles that were observed by satellites. By simultaneous assimilation of ozone profiles retrieved from the nadir looking satellite instruments Global Ozone Monitoring Experiment 2 (GOME-2) and Ozone Monitoring Instrument (OMI), which measure the atmosphere at different times of the day, the quality of the derived atmospheric ozone field has been improved. The assimilation is using an extended Kalman filter in which chemical transport model TM5 has been used for the forecast. The combined assimilation of both GOME-2 and OMI improves upon the assimilation results of a single sensor. The new assimilation system has been demonstrated by processing 4 years of data from 2008 to 2011. Validation of the assimilation output by comparison with sondes shows that biases vary between -5 and +10 % between the surface and 100 hPa. The biases for the combined assimilation vary between -3 and +3 % in the region between 100 and 10 hPa where GOME-2 and OMI are most sensitive. This is a strong improvement compared to direct retrievals of ozone profiles from satellite observations.

  15. Variability in tropical tropospheric ozone: analysis with GOME observations and a global model

    NARCIS (Netherlands)

    Valks, P.J.M.; Koelemeijer, R.B.A.; Weele, van M.; Velthoven, van P.F.J.; Fortuin, J.P.F.; Kelder, H.M.

    2003-01-01

    Tropical tropospheric ozone columns (TTOCs) have been determined with a convective-cloud-differential (CCD) method, using ozone column and cloud measurements from the Global Ozone Monitoring Experiment (GOME) instrument. GOME cloud top pressures, derived with the Fast Retrieval Scheme for Clouds

  16. An evaluation of absorption spectroscopy to monitor YBa2Cu3O7-x precursors for metal organics chemical vapor deposition processing

    International Nuclear Information System (INIS)

    Matthew Edward Thomas

    1999-01-01

    Absorption spectroscopy was evaluated as a technique to monitor the metal organics chemical vapor deposition (MOCVD) process for forming YBa 2 Cu 3 O 7-x superconducting coated conductors. Specifically, this study analyzed the feasibility of using absorption spectroscopy to monitor the MOCVD supply vapor concentrations of the organic ligand 2,2,6,6-tetramethyl-3,5-heptanedionate (TMHD) metal chelates of barium, copper, and yttrium. Ba(TMHD) 2 , Cu(TMHD) 2 , and Y(TMHD) 3 compounds have successfully been vaporized in the MOCVD processing technique to form high temperature superconducting ''coated conductors,'' a promising technology for wire fabrication. The absorption study of the barium, copper, and yttrium (TMHD) precursors was conducted in the ultraviolet wavelength region from 200nm to 400nm. To simulate the MOCVD precursor flows the Ba(TMHD) 2 , Cu(TMHD) 2 , and Y(TMHD) 3 complexes were vaporized at vacuum pressures of (0.03--10)Torr. Spectral absorption scans of each precursor were conducted to examine potential measurement wavelengths for determining vapor concentrations of each precursor via Beer's law. The experimental results show that under vacuum conditions the barium, copper, and yttrium (TMHD) precursors begin to vaporize between 90 C and 135 C, which are considerably lower vaporization temperatures than atmospheric thermal gravimetric analyses indicate. Additionally, complete vaporization of the copper and yttrium (TMHD) precursors occurred during rapid heating at temperatures between 145 C and 195 C and after heating at constant temperatures between 90 C and 125 C for approximately one hour, whereas the Ba(TMHD) 2 precursor did not completely vaporize. At constant temperatures, near constant vaporization levels for each precursor were observed for extended periods of time. Detailed spectroscopic scans at stable vaporization conditions were conducted

  17. Tropospheric ozone and its precursors from the urban to the global scale from air quality to short-lived climate forcer

    Science.gov (United States)

    Monks, P. S.; Archibald, A. T.; Colette, A.; Cooper, O.; Coyle, M.; Derwent, R.; Fowler, D.; Granier, C.; Law, K. S.; Mills, G. E.; Stevenson, D. S.; Tarasova, O.; Thouret, V.; von Schneidemesser, E.; Sommariva, R.; Wild, O.; Williams, M. L.

    2015-08-01

    Ozone holds a certain fascination in atmospheric science. It is ubiquitous in the atmosphere, central to tropospheric oxidation chemistry, yet harmful to human and ecosystem health as well as being an important greenhouse gas. It is not emitted into the atmosphere but is a byproduct of the very oxidation chemistry it largely initiates. Much effort is focused on the reduction of surface levels of ozone owing to its health and vegetation impacts, but recent efforts to achieve reductions in exposure at a country scale have proved difficult to achieve owing to increases in background ozone at the zonal hemispheric scale. There is also a growing realisation that the role of ozone as a short-lived climate pollutant could be important in integrated air quality climate change mitigation. This review examines current understanding of the processes regulating tropospheric ozone at global to local scales from both measurements and models. It takes the view that knowledge across the scales is important for dealing with air quality and climate change in a synergistic manner. The review shows that there remain a number of clear challenges for ozone such as explaining surface trends, incorporating new chemical understanding, ozone-climate coupling, and a better assessment of impacts. There is a clear and present need to treat ozone across the range of scales, a transboundary issue, but with an emphasis on the hemispheric scales. New observational opportunities are offered both by satellites and small sensors that bridge the scales.

  18. The Tropospheric Ozone Assessment Report (TOAR): A community-wide effort to quantify tropospheric ozone in a rapidly changing world

    Science.gov (United States)

    Cooper, O. R.; Schultz, M.; Paoletti, E.; Galbally, I. E.; Naja, M. K.; Tarasick, D. W.; Evans, M. J.; Thompson, A. M.

    2017-12-01

    Tropospheric ozone is a greenhouse gas and pollutant detrimental to human health and crop and ecosystem productivity. Since 1990 a large portion of the anthropogenic emissions that react in the atmosphere to produce ozone has shifted from North America and Europe to Asia. This rapid shift, coupled with limited ozone monitoring in developing nations, left scientists unable to answer the most basic questions: Which regions of the world have the greatest human and plant exposure to ozone pollution? Is ozone continuing to decline in nations with strong emissions controls? To what extent is ozone increasing in the developing world? How can the atmospheric sciences community facilitate access to the ozone metrics necessary for quantifying ozone's impact on human health and crop/ecosystem productivity? To answer these questions the International Global Atmospheric Chemistry Project (IGAC) initiated the Tropospheric Ozone Assessment Report (TOAR). With over 220 member scientists and air quality specialists from 36 nations, TOAR's mission is to provide the research community with an up-to-date scientific assessment of tropospheric ozone's global distribution and trends from the surface to the tropopause. TOAR has also built the world's largest database of surface ozone observations and generated ozone exposure and dose metrics at thousands of measurement sites around the world, freely accessible for research on the global-scale impact of ozone on climate, human health and crop/ecosystem productivity. Plots of these metrics show the regions of the world with the greatest ozone exposure for humans and crops/ecosystems, at least in areas where observations are available. The results also highlight regions where air quality is improving and where it has degraded. TOAR has also conducted the first intercomparison of tropospheric column ozone from ozonesondes and multiple satellite instruments, which provide similar estimates of the present-day tropospheric ozone burden.

  19. Generation and Reduction of NOx on Air-Fed Ozonizers

    Science.gov (United States)

    Ehara, Yoshiyasu; Amemiya, Yusuke; Yamamoto, Toshiaki

    A generation and reduction of NOx on air-fed ozonizers using a ferroelectric packed bed reactor have been experimentally investigated. The reactors packed with CaTiO3, SrTiO3 and BaTiO3 pellets are examined for ozone generation. An ac voltage is applied to the reactor to generate partial discharge. Ozone concentration and the different nitrogen oxides at downstream of the packed bed reactor were measured with UV absorption ozone monitor and a Fourier transform infrared spectroscope respectively. The dielectric constant of packed ferroelectric pellets influences the discharge characteristic, ozone and NOx generations are varied by the dielectric constant value. Focusing on a discharge pulse current and maximum discharge magnitude, the ferroelectric packed bed plasma reactors have been evaluated on nitrogen oxide and ozone generated concentrations.

  20. Ozone-induced changes in the chloroplast structure of conifer needles, and their use in ozone diagnostics

    International Nuclear Information System (INIS)

    Kivimaeenpaeae, M.; Sellden, G.; Sutinen, S.

    2005-01-01

    Ozone induces characteristic symptoms in the chloroplasts of the needles of several coniferous species. Chloroplasts are (1) reduced in size and (2) the stroma is electron dense. Moreover (3) these chloroplast alterations are more pronounced in the outer mesophyll cell layers and in the upper side of the needle compared to the inner layers and lower side. The syndrome, including the three symptoms (1)-(3), is found in the green needles of Scots pine and Norway spruce not only in the experimental fumigations, but also in mature trees in the field, and has potential for diagnosis of ozone stress. For sound ozone diagnostics all three symptoms must be present in the samples studied. The symptoms in relation to needle anatomy and physiology is discussed, and recommendations for sampling and analysis are given. - Ozone-induced alterations in chloroplast structure of conifer needles are reviewed, and recommendations for field monitoring given

  1. Estimation of surface UV levels based on Meteor-3/TOMS ozone data

    Energy Technology Data Exchange (ETDEWEB)

    Borisov, Y A [Central Aerological Observatory, Moscow (Russian Federation); Geogdzhaev, I V [Moscow Inst. of Physics and Technology, Moscow (Russian Federation); Khattatov, V U [Central Aerological Observatory, Moscow (Russian Federation)

    1996-12-31

    The major consequence of ozone layer depletion for the environment is an increase of harmful ultraviolet (UV) radiation on the Earth surface and in the upper ocean. This implies the importance of environmental UV monitoring. Since the direct global monitoring is not currently possible, indirect estimations of surface UV levels may be used based on satellite ozone data (Madronich, S. 1992). Total Ozone Mapping Spectrometer (TOMS) on board the METEOR-3 satellite provided regular set of data for such estimates. During the time of its operation (August, 1991 - December, 1994) the instrument registered several ozone hole events over Antarctica, when ozone levels dropped by as much as 60 % from their unperturbed values. Probably even more alarming ozone depletions were observed over highly populated regions of middle latitudes of northern hemisphere. Radiative transfer modeling was used to convert METEOR-3/TOMS daily ozone values into regional and global maps of biologically active UV. Calculations demonstrate the effect on surface UV levels produced by ozone hole over Antarctica and ozone depletions over the territory of Russia (March, 1994). UV contour lines deviate from the normal appearance which is determined by growing southward solar elevation. UV contour lines are almost perpendicular to the ozone ones in the ozone depletions areas. The 30 % ozone depletion, over Siberia caused more than 30 % increase in noontime erythemal UV levels, which is equivalent to 10-15 degrees southward latitude displacement. Higher UV radiation increases were found in ozone hole over South America (October 1992) equivalent to about 20 degrees southward displacement

  2. Estimation of surface UV levels based on Meteor-3/TOMS ozone data

    Energy Technology Data Exchange (ETDEWEB)

    Borisov, Y.A. [Central Aerological Observatory, Moscow (Russian Federation); Geogdzhaev, I.V. [Moscow Inst. of Physics and Technology, Moscow (Russian Federation); Khattatov, V.U. [Central Aerological Observatory, Moscow (Russian Federation)

    1995-12-31

    The major consequence of ozone layer depletion for the environment is an increase of harmful ultraviolet (UV) radiation on the Earth surface and in the upper ocean. This implies the importance of environmental UV monitoring. Since the direct global monitoring is not currently possible, indirect estimations of surface UV levels may be used based on satellite ozone data (Madronich, S. 1992). Total Ozone Mapping Spectrometer (TOMS) on board the METEOR-3 satellite provided regular set of data for such estimates. During the time of its operation (August, 1991 - December, 1994) the instrument registered several ozone hole events over Antarctica, when ozone levels dropped by as much as 60 % from their unperturbed values. Probably even more alarming ozone depletions were observed over highly populated regions of middle latitudes of northern hemisphere. Radiative transfer modeling was used to convert METEOR-3/TOMS daily ozone values into regional and global maps of biologically active UV. Calculations demonstrate the effect on surface UV levels produced by ozone hole over Antarctica and ozone depletions over the territory of Russia (March, 1994). UV contour lines deviate from the normal appearance which is determined by growing southward solar elevation. UV contour lines are almost perpendicular to the ozone ones in the ozone depletions areas. The 30 % ozone depletion, over Siberia caused more than 30 % increase in noontime erythemal UV levels, which is equivalent to 10-15 degrees southward latitude displacement. Higher UV radiation increases were found in ozone hole over South America (October 1992) equivalent to about 20 degrees southward displacement

  3. Tunable Diode Laser Heterodyne Spectrophotometry of Ozone

    Science.gov (United States)

    Fogal, P. F.; McElroy, C. T.; Goldman, A.; Murcray, D. G.

    1988-01-01

    Tunable diode laser heterodyne spectrophotometry (TDLHS) has been used to make extremely high resolution (less than 0.0005/ cm) solar spectra in the 9.6 micron ozone band. Observations have shown that a signal-to-noise ratio of 95 : 1 (35% of theoretical) for an integration time of 1/8 second can be achieved at a resolution of 0.0005 wavenumbers. The spectral data have been inverted to yield a total column amount of ozone, in good agreement with that. measured at the nearby National Oceanographic and Atmospheric Administration (NOAA) ozone monitoring facility in Boulder, Colorado.

  4. Ozone fumigation under dark/light conditions of Norway Spruce (Picea Abies) and Scots Pine (Pinus Sylvestris)

    Science.gov (United States)

    Canaval, Eva; Jud, Werner; Hansel, Armin

    2015-04-01

    Norway Spruce (Picea abies) and Scots Pine (Pinus sylvestris) represent dominating tree species in the northern hemisphere. Thus, the understanding of their ozone sensitivity in the light of the expected increasing ozone levels in the future is of great importance. In our experiments we investigated the emissions of volatile organic compounds (VOCs) of 3-4 year old Norway Spruce and Scots Pine seedlings under ozone fumigation (50-150 ppbv) and dark/light conditions. For the experiments the plants were placed in a setup with inert materials including a glass cuvette equipped with a turbulent air inlet and sensors for monitoring a large range of meteorological parameters. Typical conditions were 20-25°C and a relative humidity of 70-90 % for both plant species. A fast gas exchange rate was used to minimize reactions of ozone in the gas phase. A Switchable-Reagent-Ion-Time-of-Flight-MS (SRI-ToF-MS) was used to analyze the VOCs at the cuvette outlet in real-time during changing ozone and light levels. The use of H3O+ and NO+ as reagent ions allows the separation of certain isomers (e.g. aldehydes and ketones) due to different reaction pathways depending on the functional groups of the molecules. Within the Picea abies experiments the ozone loss, defined as the difference of the ozone concentration between cuvette inlet and outlet, remained nearly constant at the transition from dark to light. This indicates that a major part of the supplied ozone is depleted non-stomatally. In contrast the ozone loss increased by 50 % at the transition from dark to light conditions within Pinus sylvestris experiments. In this case the stomata represent the dominant loss channel. Since maximally 0.1% of the ozone loss could be explained by gas phase reactions with monoterpenes and sesquiterpenes, we suggest that ozone reactions on the surface of Picea abies represent the major sink in this case and lead to an light-independent ozone loss. This is supported by the fact that we detected

  5. A statistical model to predict total column ozone in Peninsular Malaysia

    Science.gov (United States)

    Tan, K. C.; Lim, H. S.; Mat Jafri, M. Z.

    2016-03-01

    This study aims to predict monthly columnar ozone in Peninsular Malaysia based on concentrations of several atmospheric gases. Data pertaining to five atmospheric gases (CO2, O3, CH4, NO2, and H2O vapor) were retrieved by satellite scanning imaging absorption spectrometry for atmospheric chartography from 2003 to 2008 and used to develop a model to predict columnar ozone in Peninsular Malaysia. Analyses of the northeast monsoon (NEM) and the southwest monsoon (SWM) seasons were conducted separately. Based on the Pearson correlation matrices, columnar ozone was negatively correlated with H2O vapor but positively correlated with CO2 and NO2 during both the NEM and SWM seasons from 2003 to 2008. This result was expected because NO2 is a precursor of ozone. Therefore, an increase in columnar ozone concentration is associated with an increase in NO2 but a decrease in H2O vapor. In the NEM season, columnar ozone was negatively correlated with H2O (-0.847), NO2 (0.754), and CO2 (0.477); columnar ozone was also negatively but weakly correlated with CH4 (-0.035). In the SWM season, columnar ozone was highly positively correlated with NO2 (0.855), CO2 (0.572), and CH4 (0.321) and also highly negatively correlated with H2O (-0.832). Both multiple regression and principal component analyses were used to predict the columnar ozone value in Peninsular Malaysia. We obtained the best-fitting regression equations for the columnar ozone data using four independent variables. Our results show approximately the same R value (≈ 0.83) for both the NEM and SWM seasons.

  6. Ozone impacts of natural gas development in the Haynesville Shale.

    Science.gov (United States)

    Kemball-Cook, Susan; Bar-Ilan, Amnon; Grant, John; Parker, Lynsey; Jung, Jaegun; Santamaria, Wilson; Mathews, Jim; Yarwood, Greg

    2010-12-15

    The Haynesville Shale is a subsurface rock formation located beneath the Northeast Texas/Northwest Louisiana border near Shreveport. This formation is estimated to contain very large recoverable reserves of natural gas, and during the two years since the drilling of the first highly productive wells in 2008, has been the focus of intensive leasing and exploration activity. The development of natural gas resources within the Haynesville Shale is likely to be economically important but may also generate significant emissions of ozone precursors. Using well production data from state regulatory agencies and a review of the available literature, projections of future year Haynesville Shale natural gas production were derived for 2009-2020 for three scenarios corresponding to limited, moderate, and aggressive development. These production estimates were then used to develop an emission inventory for each of the three scenarios. Photochemical modeling of the year 2012 showed increases in 2012 8-h ozone design values of up to 5 ppb within Northeast Texas and Northwest Louisiana resulting from development in the Haynesville Shale. Ozone increases due to Haynesville Shale emissions can affect regions outside Northeast Texas and Northwest Louisiana due to ozone transport. This study evaluates only near-term ozone impacts, but the emission inventory projections indicate that Haynesville emissions may be expected to increase through 2020.

  7. Tropospheric ozone over Equatorial Africa: regional aspects from the MOZAIC data

    Directory of Open Access Journals (Sweden)

    B. Sauvage

    2005-01-01

    Full Text Available We analyze ozone observations recorded over Equatorial Africa between April 1997 and March 2003 by the MOZAIC programme, providing the first ozone climatology deriving from continental in-situ data over this region. Three-dimensional streamlines strongly suggests connections between the characteristics of the ozone monthly mean vertical profiles, the most persistent circulation patterns in the troposphere over Equatorial Africa (on a monthly basis such as the Harmattan, the African Easterly Jet, the Trades and the regions of ozone precursors emissions by biomass burning. During the biomass burning season in each hemisphere, the lower troposphere exhibits layers of enhanced ozone (i.e. 70 ppbv over the coast of Gulf of Guinea in December-February and 85 ppbv over Congo in June-August. The characteristics of the ozone monthly mean vertical profiles are clearly connected to the regional flow regime determined by seasonal dynamic forcing. The mean ozone profile over the coast of Gulf of Guinea in the burning season is characterized by systematically high ozone below 650hPa ; these are due to the transport by the Harmattan and the AEJ of the pollutants originating from upwind fires. The confinement of high ozone to the lower troposphere is due to the high stability of the Harmattan and the blocking Saharan anticyclone which prevents efficient vertical mixing. In contrast, ozone enhancements observed over Central Africa during the local dry season (June-August are not only found in the lower troposphere but throughout the troposphere. Moreover, this study highlights a connection between the regions of the coast of Gulf of Guinea and regions of Congo to the south that appears on a semi annual basis. Vertical profiles in wet-season regions exhibit ozone enhancements in the lower troposphere due to biomass burning products transport from fires situated in the opposite dry-season hemisphere.

  8. Ozone concentrations and damage for realistic future European climate and air quality scenarios

    NARCIS (Netherlands)

    Hendriks, C.; Forsell, N.; Kiesewetter, G.; Schaap, M.; Schöpp, W.

    2016-01-01

    Ground level ozone poses a significant threat to human health from air pollution in the European Union. While anthropogenic emissions of precursor substances (NOx, NMVOC, CH4) are regulated by EU air quality legislation and will decrease further in the future, the emissions of biogenic NMVOC (mainly

  9. Ground-level ozone in China: Distribution and effects on crop yields

    International Nuclear Information System (INIS)

    Wang Xiaoke; Manning, William; Feng Zongwei; Zhu Yongguan

    2007-01-01

    Rapid economic development and an increasing demand for food in China have drawn attention to the role of ozone at pollution levels on crop yields. Some assessments of ozone effects on crop yields have been carried out in China. Determination of ozone distribution by geographical location and resulting crop loss estimations have been made by Chinese investigators and others from abroad. It is evident that surface level ozone levels in China exceed critical levels for occurrence of crop losses. Current levels of information from ozone dose/response studies are limited. Given the size of China, existing ozone monitoring sites are too few to provide enough data to scale ozone distribution to a national level. There are large uncertainties in the database for ozone effects on crop loss and for ozone distribution. Considerable research needs to be done to allow accurate estimation of crop losses caused by ozone in China. - More research is needed to reliably estimate ozone caused crop losses in China

  10. Assimilated ozone from EOS-Aura: Evaluation of the tropopause region and tropospheric columns

    NARCIS (Netherlands)

    Stajner, I.; Wargan, K.; Pawson, S.; Hayashi, H.; Chang, L.-P.; Hudman, R.C.; Froidevaux, L.; Livesey, N.J.; Levelt, P.F.; Thompson, A.M.; Tarasick, D.W.; Stübi, R.; Andersen, S.B.; Yela, M.; König-Langlo, G.; Schmidlin, F.J.; Witte, J.C.

    2008-01-01

    Retrievals from the Microwave Limb Sounder (MLS) and the Ozone Monitoring Instrument (OMI) on EOS-Aura were included in the Goddard Earth Observing System version 4 (GEOS-4) ozone data assimilation system. The distribution and daily to seasonal evolution of ozone in the stratosphere and troposphere

  11. Climate and air quality-driven scenarios of ozone and aerosol precursor abatement

    International Nuclear Information System (INIS)

    Rypdal, Kristin; Rive, Nathan; Berntsen, Terje; Fagerli, Hilde; Klimont, Zbigniew; Mideksa, Torben K.; Fuglestvedt, Jan S.

    2009-01-01

    In addition to causing domestic and regional environmental effects, many air pollutants contribute to radiative forcing (RF) of the climate system. However, climate effects are not considered when cost-effective abatement targets for these pollutants are established, nor are they included in current international climate agreements. We construct air pollution abatement scenarios in 2030 which target cost-effective reductions in RF in the EU, USA, and China and compare these to abatement scenarios which instead target regional ozone effects and particulate matter concentrations. Our analysis covers emissions of PM (fine, black carbon and organic carbon), SO 2 , NO x , CH 4 , VOCs, and CO. We find that the effect synergies are strong for PM/BC, VOC, CO and CH 4 . While an air quality strategy targeted at reducing ozone will also reduce RF, this will not be the case for a strategy targeting particulate matter. Abatement in China dominates RF reduction, but there are cheap abatement options also available in the EU and USA. The justification for international cooperation on air quality issues is underlined when the co-benefits of reduced RF are considered. Some species, most importantly SO 2 , contribute a negative forcing on climate. We suggest that given current knowledge, NO x and SO 2 should be ignored in RF-targeted abatement policies.

  12. A statistical model for forecasting hourly ozone levels during fire season

    Science.gov (United States)

    Haiganoush K. Preisler; Shiyuan (Sharon) Zhong; Annie Esperanza; Leland Tarnay; Julide Kahyaoglu-Koracin

    2009-01-01

    Concerns about smoke from large high-intensity and managed low intensity fires have been increasing during the past decade. Because smoke from large high-intensity fires are known to contain and generate secondary fine particles (PM2.5) and ozone precursors, the effect of fires on air quality in the southern Sierra Nevada is a serious management...

  13. Electrical properties of GaN-based metal-insulator-semiconductor structures with Al2O3 deposited by atomic layer deposition using water and ozone as the oxygen precursors

    Science.gov (United States)

    Kubo, Toshiharu; Freedsman, Joseph J.; Iwata, Yasuhiro; Egawa, Takashi

    2014-04-01

    Al2O3 deposited by atomic layer deposition (ALD) was used as an insulator in metal-insulator-semiconductor (MIS) structures for GaN-based MIS-devices. As the oxygen precursors for the ALD process, water (H2O), ozone (O3), and both H2O and O3 were used. The chemical characteristics of the ALD-Al2O3 surfaces were investigated by x-ray photoelectron spectroscopy. After fabrication of MIS-diodes and MIS-high-electron-mobility transistors (MIS-HEMTs) with the ALD-Al2O3, their electrical properties were evaluated by current-voltage (I-V) and capacitance-voltage (C-V) measurements. The threshold voltage of the C-V curves for MIS-diodes indicated that the fixed charge in the Al2O3 layer is decreased when using both H2O and O3 as the oxygen precursors. Furthermore, MIS-HEMTs with the H2O + O3-based Al2O3 showed good dc I-V characteristics without post-deposition annealing of the ALD-Al2O3, and the drain leakage current in the off-state region was suppressed by seven orders of magnitude.

  14. Estimating changes in urban ozone concentrations due to life cycle emissions from hydrogen transportation systems

    Science.gov (United States)

    Wang, Guihua; Ogden, Joan M.; Chang, Daniel P. Y.

    Hydrogen has been proposed as a low polluting alternative transportation fuel that could help improve urban air quality. This paper examines the potential impact of introducing a hydrogen-based transportation system on urban ambient ozone concentrations. This paper considers two scenarios, where significant numbers of new hydrogen vehicles are added to a constant number of gasoline vehicles. In our scenarios hydrogen fuel cell vehicles (HFCVs) are introduced in Sacramento, California at market penetrations of 9% and 20%. From a life cycle analysis (LCA) perspective, considering all the emissions involved in producing, transporting, and using hydrogen, this research compares three hypothetical natural gas to hydrogen pathways: (1) on-site hydrogen production; (2) central hydrogen production with pipeline delivery; and (3) central hydrogen production with liquid hydrogen truck delivery. Using a regression model, this research shows that the daily maximum temperature correlates well with atmospheric ozone formation. However, increases in initial VOC and NO x concentrations do not necessarily increase the peak ozone concentration, and may even cause it to decrease. It is found that ozone formation is generally limited by NO x in the summer and is mostly limited by VOC in the fall in Sacramento. Of the three hydrogen pathways, the truck delivery pathway contributes the most to ozone precursor emissions. Ozone precursor emissions from the truck pathway at 9% market penetration can cause additional 3-h average VOC (or NO x) concentrations up to approximately 0.05% (or 1%) of current pollution levels, and at 20% market penetration up to approximately 0.1% (or 2%) of current pollution levels. However, all of the hydrogen pathways would result in very small (either negative or positive) changes in ozone air quality. In some cases they will result in worse ozone air quality (mostly in July, August, and September), and in some cases they will result in better ozone air quality

  15. Estimating changes in urban ozone concentrations due to life cycle emissions from hydrogen transportation systems

    International Nuclear Information System (INIS)

    Guihua Wang; Ogden, Joan M.; Chang, Daniel P.Y.

    2007-01-01

    Hydrogen has been proposed as a low polluting alternative transportation fuel that could help improve urban air quality. This paper examines the potential impact of introducing a hydrogen-based transportation system on urban ambient ozone concentrations. This paper considers two scenarios, where significant numbers of new hydrogen vehicles are added to a constant number of gasoline vehicles. In our scenarios hydrogen fuel cell vehicles (HFCVs) are introduced in Sacramento, California at market penetrations of 9% and 20%. From a life cycle analysis (LCA) perspective, considering all the emissions involved in producing, transporting, and using hydrogen, this research compares three hypothetical natural gas to hydrogen pathways: (1) on-site hydrogen production; (2) central hydrogen production with pipeline delivery; and (3) central hydrogen production with liquid hydrogen truck delivery. Using a regression model, this research shows that the daily maximum temperature correlates well with atmospheric ozone formation. However, increases in initial VOC and NO x concentrations do not necessarily increase the peak ozone concentration, and may even cause it to decrease. It is found that ozone formation is generally limited by NO x in the summer and is mostly limited by VOC in the fall in Sacramento. Of the three hydrogen pathways, the truck delivery pathway contributes the most to ozone precursor emissions. Ozone precursor emissions from the truck pathway at 9% market penetration can cause additional 3-h average VOC (or NO x ) concentrations up to approximately 0.05% (or 1%) of current pollution levels, and at 20% market penetration up to approximately 0.1% (or 2%) of current pollution levels. However, all of the hydrogen pathways would result in very small (either negative or positive) changes in ozone air quality. In some cases they will result in worse ozone air quality (mostly in July, August, and September), and in some cases they will result in better ozone air

  16. SUMO: Solar Ultraviolet Monitor and Ozone Nanosatellite

    Science.gov (United States)

    Damé, L.; Meftah, M.; Irbah, A.; Hauchecorne, A.; Keckhut, P.; Sarkissian, A.; Godin-Beekman, S.; Rogers, D. J.; Bove, P.; Lagage, P. O.; DeWitte, S.

    2014-12-01

    SUMO is an innovative proof-of-concept nanosatellite aiming to measure on the same platform the different components of the Earth radiation budget (ERB), the solar energy input and the energy reemitted at the top of the Earth atmosphere, with a particular focus on the far UV (FUV) part of the spectrum and on the ozone layer. The FUV is the only wavelength band with energy absorbed in the high atmosphere (stratosphere), in the ozone (Herzberg continuum, 200-220 nm) and oxygen bands, and its high variability is most probably at the origin of a climate influence (UV affects stratospheric dynamics and temperatures, altering interplanetary waves and weather patterns both poleward and downward to the lower stratosphere and tropopause). A simultaneous observation of incoming FUV and ozone production would bring an invaluable information on this process of solar-climate forcing. Space instruments have already measured the different components of the ERB but this is the first time that all instruments will operate on the same platform. This characteristic by itself guarantees original scientific results. SUMO is a 3.6 kg, 3W, 10x10x30 cm3 nanosatellite ("3U"), with a "1U" payload of definition has been completed (platform and payload AIT are possible in 24 months). SUMO is proposed for the nanosatellite program of Polytechnic School and CNES (following QB50) for a flight in 2018. Follow-up is 2 fold: on one part more complete measurements using SUMO miniaturized instruments on a larger satellite; on the other part, increase of the coverage in local time and latitude using a constellation of SUMO nanosatellites around the Earth to further geolocalize the Sun influence on our planet. Nanosatellites, with cost and risk limited, are also excellent platforms to evaluate technologies for future missions, e.g. nanotechnology ZnO protection barriers to limit contamination from solar panels in the UV and reduce reflection losses in the visible, or MgZnO solar blind detectors (R

  17. Ozone decomposition kinetics on alumina: effects of ozone partial pressure, relative humidity and repeated oxidation cycles

    Directory of Open Access Journals (Sweden)

    R. C. Sullivan

    2004-01-01

    Full Text Available The room temperature kinetics of gas-phase ozone loss via heterogeneous interactions with thin alumina films has been studied in real-time using 254nm absorption spectroscopy to monitor ozone concentrations. The films were prepared from dispersions of fine alumina powder in methanol and their surface areas were determined by an in situ procedure using adsorption of krypton at 77K. The alumina was found to lose reactivity with increasing ozone exposure. However, some of the lost reactivity could be recovered over timescales of days in an environment free of water, ozone and carbon dioxide. From multiple exposures of ozone to the same film, it was found that the number of active sites is large, greater than 1.4x1014 active sites per cm2 of surface area or comparable to the total number of surface sites. The films maintain some reactivity at this point, which is consistent with there being some degree of active site regeneration during the experiment and with ozone loss being catalytic to some degree. The initial uptake coefficients on fresh films were found to be inversely dependent on the ozone concentration, varying from roughly 10-6 for ozone concentrations of 1014 molecules/cm3 to 10-5 at 1013 molecules/cm3. The initial uptake coefficients were not dependent on the relative humidity, up to 75%, within the precision of the experiment. The reaction mechanism is discussed, as well as the implications these results have for assessing the effect of mineral dust on atmospheric oxidant levels.

  18. Satellite Ozone Analysis Center (SOAC)

    International Nuclear Information System (INIS)

    Lovill, J.E.; Sullivan, T.J.; Knox, J.B.; Korver, J.A.

    1976-08-01

    Many questions have been raised during the 1970's regarding the possible modification of the ozonosphere by aircraft operating in the stratosphere. Concern also has been expressed over the manner in which the ozonosphere may change in the future as a result of fluorocarbon releases. There are also other ways by which the ozonosphere may be significantly altered, both anthropogenic and natural. Very basic questions have been raised, bearing upon the amount of ozone which would be destroyed by the NO/sub x/ produced in atmospheric nuclear explosions. Studies of the available satellite data have suggested that the worldwide increase of ozone during the past decade, which was observed over land stations, may have been biased by a poor distribution of stations and/or a shift of the planetary wave. Additional satellite data will be required to resolve this issue. Proposals are presented for monitoring of the Earth's ozone variability from the present time into the 1980's to establish a baseline upon which regional, as well as global, ozone trends can be measured

  19. Production and Transport of Ozone From Boreal Forest Fires

    Science.gov (United States)

    Tarasick, David; Liu, Jane; Osman, Mohammed; Sioris, Christopher; Liu, Xiong; Najafabadi, Omid; Parrington, Mark; Palmer, Paul; Strawbridge, Kevin; Duck, Thomas

    2013-04-01

    In the summer of 2010, the BORTAS (Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites) mission was planned by several universities and government agencies in the United Kingdom, Canada, and USA. Nearly 100 ozone soundings were made at 13 stations through the BORTAS Intensive Sounding Network, although aircraft measurements were unfortunately cancelled due to the volcanic eruption in Iceland. 2010 was actually an exceptional year for Canadian boreal fires. MODIS (Moderate Resolution Imaging Spectroradiometer) fire count data shows large fire events in Saskatchewan on several days in July. High amounts of NO2 close to the large fires are observed from OMI satellite data, indicating that not all NO2 is converted to PAN. Also associated with the fires, large amounts of CO, another precursor of ozone, are observed in MOPITT (Measurements Of Pollution In The Troposphere), AIRS and TES (Tropospheric Emission Spectrometer) satellite data in the middle to upper troposphere. These chemical conditions combined with sunny weather all favour ozone production. Following days with large fire activity, layers of elevated ozone mixing ratio (over 100 ppbv) are observed downwind at several sites. Back-trajectories suggest the elevated ozone in the profile is traceable to the fires in Saskatchewan. Lidar profiles also detect layers of aerosol at the same heights. However, the layers of high ozone are also associated with low humidity, which is not expected from a combustion source, and suggests the possibility of entrainment of stratospheric air.

  20. Influence of local meteorology and NO2 conditions on ground-level ozone concentrations in the eastern part of Texas, USA.

    Science.gov (United States)

    Gorai, A K; Tuluri, F; Tchounwou, P B; Ambinakudige, S

    2015-02-01

    The influence of local climatic factors on ground-level ozone concentrations is an area of increasing interest to air quality management in regards to future climate change. This study presents an analysis on the role of temperature, wind speed, wind direction, and NO 2 level on ground-level ozone concentrations over the region of Eastern Texas, USA. Ozone concentrations at the ground level depend on the formation and dispersion processes. Formation process mainly depends on the precursor sources, whereas, the dispersion of ozone depends on meteorological factors. Study results showed that the spatial mean of ground-level ozone concentrations was highly dependent on the spatial mean of NO 2 concentrations. However, spatial distributions of NO 2 and ozone concentrations were not uniformed throughout the study period due to uneven wind speeds and wind directions. Wind speed and wind direction also played a significant role in the dispersion of ozone. Temperature profile in the area rarely had any effects on the ozone concentrations due to low spatial variations.

  1. Climate-driven ground-level ozone extreme in the fall over the Southeast United States.

    Science.gov (United States)

    Zhang, Yuzhong; Wang, Yuhang

    2016-09-06

    Ground-level ozone is adverse to human and vegetation health. High ground-level ozone concentrations usually occur over the United States in the summer, often referred to as the ozone season. However, observed monthly mean ozone concentrations in the southeastern United States were higher in October than July in 2010. The October ozone average in 2010 reached that of July in the past three decades (1980-2010). Our analysis shows that this extreme October ozone in 2010 over the Southeast is due in part to a dry and warm weather condition, which enhances photochemical production, air stagnation, and fire emissions. Observational evidence and modeling analysis also indicate that another significant contributor is enhanced emissions of biogenic isoprene, a major ozone precursor, from water-stressed plants under a dry and warm condition. The latter finding is corroborated by recent laboratory and field studies. This climate-induced biogenic control also explains the puzzling fact that the two extremes of high October ozone both occurred in the 2000s when anthropogenic emissions were lower than the 1980s and 1990s, in contrast to the observed decreasing trend of July ozone in the region. The occurrences of a drying and warming fall, projected by climate models, will likely lead to more active photochemistry, enhanced biogenic isoprene and fire emissions, an extension of the ozone season from summer to fall, and an increase of secondary organic aerosols in the Southeast, posing challenges to regional air quality management.

  2. Seasonal behavior and long-term trends of tropospheric ozone, its precursors and chemical conditions over Iran: A view from space

    Science.gov (United States)

    Choi, Yunsoo; Souri, Amir Hossein

    2015-04-01

    To identify spatial and temporal variations over the Iranian region, this study analyzed tropospheric formaldehyde (HCHO) and nitrogen dioxide (NO2) columns from Ozone Monitoring Instrument (OMI), carbon monoxide (CO) columns from the Measurement of Pollution in the Troposphere (MOPITT), and tropospheric column O3 (TCO) from OMI/MLS (Microwave Limb Sounder) satellites from 2005 to 2012. The study discovered high levels of HCHO (∼12 × 1015 molec./cm2) from plant isoprene emissions in the air above parts of the northern forest of Iran during the summer and from the oxidation of HCHO precursors emitted from petrochemical industrial facilities and biomass burning in South West Iran. This study showed that maximum NO2 levels (∼18 × 1015 molec./cm2) were concentrated in urban cities, indicating the predominance of anthropogenic sources. The results indicate that maximum concentrations were found in the winter, mainly because of weaker local winds and higher heating fuel consumption, in addition to lower hydroxyl radicals (OH). The high CO concentrations (∼2 × 1018 molec./cm2) in the early spring were inferred to mainly originate from a strong continental air mass from anthropogenic CO "hotspots" including regions around Caspian Sea, Europe, and North America, although the external sources of CO were partly suppressed by the Arabian anticyclone and topographic barriers. Variations in the TCO were seen to peak during the summer (∼40 DU), due to intensive solar radiation and stratospheric sources. This study also examined long-term trends in TCO and its precursors over a period of eight years in five urban cities in Iran. To perform the analysis, we estimated seasonal changes and inter-seasonal variations using least-squares harmonic estimation (LS-HE), which reduced uncertainty in the trend by 5-15%. The results showed significant increases in the levels of HCHO (∼0.08 ± 0.06 × 1015 molec./cm2 yr-1), NO2 (∼0.08 ± 0.02 × 1015 molec./cm2 yr-1), and peak

  3. Godiva, a European Project for Ozone and Trace Gas Measurements from GOME

    Science.gov (United States)

    Goede, A. P. H.; Tanzi, C. P.; Aben, I.; Burrows, J. P.; Weber, M.; Perner, D.; Monks, P. S.; Llewellyn-Jones, D.; Corlett, G. K.; Arlander, D. W.; Platt, U.; Wagner, T.; Pfeilsticker, K.; Taalas, P.; Kelder, H.; Piters, A.

    GODIVA (GOME Data Interpretation, Validation and Application) is a European Commission project aimed at the improvement of GOME (Global Ozone Monitoring Experiment) data products. Existing data products include global ozone, NO2 columns and (ir)radiances. Advanced data products include O3 profiles, BrO, HCHO and OCIO columns. These data are validated by ground-based and balloon borne instruments. Calibration issues are investigated by in-flight monitoring using several complementary calibration sources, as well as an on-ground replica of the GOME instrument. The results will lead to specification of operational processing of the EUMETSAT ozone Satellite Application Facility as well as implementation of the improved and new GOME data products in the NILU database for use in the European THESEO (Third European Stratospheric Experiment on Ozone) campaign of 1999

  4. Effects of ozone as a stand-alone and coagulation-aid treatment on the reduction of trihalomethanes precursors from high DOC and hardness water.

    Science.gov (United States)

    Sadrnourmohamadi, Mehrnaz; Gorczyca, Beata

    2015-04-15

    This study investigates the effect of ozone as a stand-alone and coagulation aid on the removal of dissolved organic carbon (DOC) from the water with a high level of DOC (13.8 mgL(-1)) and calcium hardness (270 mgL(-1)) CaCO3. Natural water collected from the Assiniboine River (Manitoba, Canada) was used in this study. Effectiveness of ozone treatment was evaluated by measurement of DOC, DOC fractions, UV254, and trihalomethane formation potential (THMFP). Additionally, zeta potential and dissolved calcium concentration were measured to discern the mechanism of ozone reactions. Results indicated that 0.8 mg O3/mg DOC ozone stand-alone can cause up to 86% UV254 reduction and up to 27% DOC reduction. DOC fractionation results showed that ozone can change the composition of DOC in the water samples, converting the hydrophobic fractions into hydrophilic ones and resulting in the reduction of THMFP. Also, ozone caused a decrease in particle stability and dissolved calcium concentration. These simultaneous ozonation effects caused improved water flocculation and enhanced removal of DOC. This resulted in reduction of the coagulant dosage when ozone doses higher than 0.2 mg O3/mg DOC were applied prior to coagulation with ferric sulfate. Also, pre-ozonation-coagulation process achieved preferential THMFP removal for all of the ozone doses tested (0-0.8 mg O3/mg DOC), leading to a lower specific THMFP in pre-ozonated-coagulated waters than in the corresponding ozonated waters. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. When will the Antarctic Ozone Hole Recover?

    Science.gov (United States)

    Newman, Paul A.; Nash, Eric R.; Kawa, S. Randolph; Montzka, Steve

    2006-01-01

    The Antarctic ozone hole develops each year and culminates by early Spring. Antarctic ozone values have been monitored since 1979 using satellite observations from the .TOMS instrument. The severity of the hole has been assessed from TOMS using the minimum total ozone value from the October monthly mean (depth of the hole) and by calculating the average size during the September-October period. Ozone is mainly destroyed by halogen catalytic cycles, and these losses are modulated by temperature variations in the collar of the polar lower stratospheric vortex. In this presentation, we show the relationships of halogens and temperature to, both the size and depth of the hole. Because atmospheric halogen levels are responding to international agreements that limit or phase out production, the amount of halogens in the stratosphere should decrease over the next few decades. Using projections of halogen levels combined with age-of-air estimates, we find that the ozone hole is recovering at an extremely slow rate and that large ozone holes will regularly recur over the next 2 decades. The ozone hole will begin to show first signs of recovery in about 2023, and the hole will fully recover to pre-1980 levels in approximately 2070. This 2070 recovery is 20 years later than recent projections.

  6. Nicotiana tabacum as model for ozone - plant surface reactions

    Science.gov (United States)

    Jud, Werner; Fischer, Lukas; Wohlfahrt, Georg; Tissier, Alain; Canaval, Eva; Hansel, Armin

    2015-04-01

    Elevated tropospheric ozone concentrations are considered a toxic threat to plants, responsible for global crop losses with associated economic costs of several billion dollars per year. The ensuing injuries have been related to the uptake of ozone through the stomatal pores and oxidative effects damaging the internal leaf tissue. A striking question of current research is the environment and plant specific partitioning of ozone loss between gas phase, stomatal or plant surface sink terms. Here we show results from ozone fumigation experiments using various Nicotiana Tabacum varieties, whose surfaces are covered with different amounts of unsaturated diterpenoids exuded by their glandular trichomes. Exposure to elevated ozone levels (50 to 150 ppbv) for 5 to 15 hours in an exceptionally clean cuvette system did neither result in a reduction of photosynthesis nor caused any visible leaf damage. Both these ozone induced stress effects have been observed previously in ozone fumigation experiments with the ozone sensitive tobacco line Bel-W3. In our case ozone fumigation was accompanied by a continuous release of oxygenated volatile organic compounds, which could be clearly associated to their condensed phase precursors for the first time. Gas phase reactions of ozone were avoided by choosing a high enough gas exchange rate of the plant cuvette system. In the case of the Ambalema variety, that is known to exude only the diterpenoid cis-abienol, ozone fumigation experiments yield the volatiles formaldehyde and methyl vinyl ketone (MVK). The latter could be unequivocally separated from isomeric methacrolein (MACR) by the aid of a Selective Reagent Ion Time-of-Flight Mass Spectrometer (SRI-ToF-MS), which was switched every six minutes from H3O+ to NO+ primary ion mode and vice versa. Consistent with the picture of an ozone protection mechanism caused by reactive diterpenoids at the leaf surface are the results from dark-light experiments. The ozone loss obtained from the

  7. Monitoring changes in the structure and properties of humic substances following ozonation using UV-Vis, FTIR and (1)H NMR techniques.

    Science.gov (United States)

    Rodríguez, Francisco J; Schlenger, Patrick; García-Valverde, María

    2016-01-15

    The main objective of this work is to conduct a comprehensive structural characterization of humic substances using the following experimental techniques: FTIR, 1H NMR and several UV–Vis parameters (Specific UV Absorbance at 254 nm or SUVA254, SUVA280, A400, the absorbance ratios A210/254, A250/365, A254/203, A254/436, A265/465, A270/400, A280/350, A465/665, the Absorbance Slope Index (ASI), the spectral slopes S275–295, S350–400 and the slope ratio SR). These UV–Vis parameters have also been correlated with key properties of humic substances such as aromaticity, molecular weight (MW) and trihalomethane formation potential (THMFP). An additional objective of this work is also to evaluate the usefulness of these techniques to monitor structural changes in humic substances produced by the ozonation treatment. Four humic substances were studied in this work: three of them were provided by the International Humic Substances Society (Suwannee River Fulvic Acid Standard: SRFA, Suwannee River Humic Acid Standard: SRHA and Nordic Reservoir Fulvic Acid Reference: NLFA) and the other one was a terrestrial humic acid widely used as a surrogate for aquatic humic substances in various studies (Aldrich Humic Acid: AHA). The UV–Vis parameters showing the best correlations with aromaticity in this study were SUVA254, SUVA280, A280/A350 ratio and A250/A364 ratio. The best correlations with molecular weight were for SUVA254, SUVA280 and A280/A350 ratio. Finally, in the case of the THMFP it was STHMFP-per mol HS the parameter showing good correlations with most of the UV–Vis parameters studied (especially with A280/A350 ratio, A265/A465 ratio and A270/A400 ratio) whereas STHMFP-per mg C showed poor correlations in most cases. On the whole, the UV–Vis parameter showing the best results was A280/A350 ratio as it showed excellent correlations for the three properties studied (aromaticity, MW and THMFP). A decrease in aromaticity following ozonation of humic substances can

  8. 1979-1999 satellite total ozone column measurements over West Africa

    Directory of Open Access Journals (Sweden)

    P. Di Carlo

    2000-06-01

    Full Text Available Total Ozone Mapping Spectrometer (TOMS instruments have been flown on NASA/GSFC satellites for over 20 years. They provide near real-time ozone data for Atmospheric Science Research. As part of preliminary efforts aimed to develop a Lidar station in Nigeria for monitoring the atmospheric ozone and aerosol levels, the monthly mean TOMS total column ozone measurements between 1979 to 1999 have been analysed. The trends of the total column ozone showed a spatial and temporal variation with signs of the Quasi Biennial Oscillation (QBO during the 20-year study period. The values of the TOMS total ozone column, over Nigeria (4-14°N is within the range of 230-280 Dobson Units, this is consistent with total ozone column data, measured since April 1993 with a Dobson Spectrophotometer at Lagos (3°21¢E, 6°33¢N, Nigeria.

  9. TROPOMI on the Copernicus Sentinel 5 Precursor: Launched?

    Science.gov (United States)

    Levelt, P.; Veefkind, J. P.; Kleipool, Q.; Ludewig, A.; Aben, I.; De Vries, J.; Loyola, D. G.; Richter, A.; Van Roozendael, M.; Siddans, R.; Tamminen, J.; Wagner, T.; Nett, H.

    2016-12-01

    The Copernicus Sentinel 5 Precursor (S5P) is the first of the European Sentinels satellites dedicated to monitoring of the atmospheric composition. S5P is planned for launch in the 4thquarter of 2016; hopefully in time for the AGU Fall Meeting! The mission objectives of S5P are to monitor air quality, climate and the ozone layer, in the time period between 2017 and 2023. S5P will fly in a Sun-synchronized polar orbit with a 13:30 hr local equator crossing time. The single payload of the S5P mission is TROPOspheric Monitoring Instrument (TROPOMI), which is developed by The Netherlands in cooperation with the European Space Agency (ESA). TROPOMI is a nadir viewing shortwave spectrometer that measures in the UV-visible wavelength range (270-500 nm), the near infrared (710-770 nm) and the shortwave infrared (2314-2382 nm). TROPOMI will have an unprecedented spatial resolution of 7x7 km2at nadir. The spatial resolution is combined with a wide swath to allow for daily global coverage. The TROPOMI/S5P geophysical (Level 2) operational data products include nitrogen dioxide, carbon monoxide, ozone (total column, tropospheric column & profile), methane, sulfur dioxide, formaldehyde and aerosol and cloud parameters. The main heritage for TROPOMI comes from OMI on EOS Aura and SCIAMACHY on Envisat. Many of the lessons learned in these missions have resulted in design improvements for TROPOMI. One of the most striking features is the high spatial resolution of 7x7 km2at nadir. The high spatial resolution serves two goals: (1) emissions sources can be detected with a higher accuracy and (2) the number of cloud-free ground pixels will increase substantially. The higher spatial resolution is also combined with a significantly higher signal-to-noise ratio per ground pixel, compared to OMI. This will further enhance the capabilities of TROPOMI to detect small emissions sources. The S5P will fly in a so-called loose formation with the U.S. Suomi NPP (National Polar

  10. Ozone initiated reactions and human comfort in indoor environments

    DEFF Research Database (Denmark)

    Tamas, Gyöngyi

    2006-01-01

    Chemical reactions between ozone and pollutants commonly found indoors have been suggested to cause adverse health and comfort effects among building occupants. Of special interest are reactions with terpenes and other pollutants containing unsaturated carbon-carbon bonds that are fast enough...... to occur under normal conditions in various indoor settings. These reactions are known to occur both in the gas phase (homogeneous reactions) and on the surfaces of building materials (heterogeneous reactions), producing a number of compounds that can be orders of magnitude more odorous and irritating than...... their precursors. The present thesis investigates the effects of ozone-initiated reactions with limonene and with various interior surfaces, including those associated with people, on short-term sensory responses. The evaluations were conducted using a perceived air quality (PAQ) method introduced by Fanger (1988...

  11. Impact of climate change on tropospheric ozone and its global budgets

    Directory of Open Access Journals (Sweden)

    G. Zeng

    2008-01-01

    Full Text Available We present the chemistry-climate model UMCAM in which a relatively detailed tropospheric chemical module has been incorporated into the UK Met Office's Unified Model version 4.5. We obtain good agreements between the modelled ozone/nitrogen species and a range of observations including surface ozone measurements, ozone sonde data, and some aircraft campaigns.

    Four 2100 calculations assess model responses to projected changes of anthropogenic emissions (SRES A2, climate change (due to doubling CO2, and idealised climate change-associated changes in biogenic emissions (i.e. 50% increase of isoprene emission and doubling emissions of soil-NOx. The global tropospheric ozone burden increases significantly for all the 2100 A2 simulations, with the largest response caused by the increase of anthropogenic emissions. Climate change has diverse impacts on O3 and its budgets through changes in circulation and meteorological variables. Increased water vapour causes a substantial ozone reduction especially in the tropical lower troposphere (>10 ppbv reduction over the tropical ocean. On the other hand, an enhanced stratosphere-troposphere exchange of ozone, which increases by 80% due to doubling CO2, contributes to ozone increases in the extratropical free troposphere which subsequently propagate to the surface. Projected higher temperatures favour ozone chemical production and PAN decomposition which lead to high surface ozone levels in certain regions. Enhanced convection transports ozone precursors more rapidly out of the boundary layer resulting in an increase of ozone production in the free troposphere. Lightning-produced NOx increases by about 22% in the doubled CO2 climate and contributes to ozone production.

    The response to the increase of isoprene emissions shows that the change of ozone is largely determined by background NOx levels: high

  12. Influence of turbidity and clouds on satellite total ozone data over Madrid (Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Camacho, J.L. [Agencia Estatal de Meteorologia (AEMET), Madrid (Spain); Anton, M. [Granada Univ. (Spain). Dept. de Fisica Aplicada; Loyola, D. [German Aerospace Center (DLR), Wessling (DE). Remote Sensing Technology Inst. (IMF); Hernandez, E. [Madrid Univ. Complutense (Spain). Dept. Fisica de la Tierra II

    2010-07-01

    This article focuses on the comparison of the total ozone column data from three satellite instruments; Total Ozone Mapping Spectrometers (TOMS) on board the Earth Probe (EP), Ozone Monitoring Instrument (OMI) on board AURA and Global Ozone Monitoring Experiment (GOME) on board ERS/2, with ground-based measurement recorded by a well calibrated Brewer spectrophotometer located in Madrid during the period 1996-2008. A cluster classification based on solar radiation (global, direct and diffuse), cloudiness and aerosol index allow selecting hazy, cloudy, very cloudy and clear days. Thus, the differences between Brewer and satellite total ozone data for each cluster have been analyzed. The accuracy of EP-TOMS total ozone data is affected by moderate cloudiness, showing a mean absolute bias error (MABE) of 2.0%. In addition, the turbidity also has a significant influence on EP-TOMS total ozone data with a MABE {proportional_to}1.6%. Those data are in contrast with clear days with MABE {proportional_to}1.2%. The total ozone data derived from the OMI instrument show clear bias at clear and hazy days with small uncertainties ({proportional_to}0.8%). Finally, the total ozone observations obtained with the GOME instrument show a very smooth dependence with respect to clouds and turbidity, showing a robust retrieval algorithm over these conditions. (orig.)

  13. Ozone mixing ratios inside tropical deep convective clouds from OMI satellite measurements

    Directory of Open Access Journals (Sweden)

    J. R. Ziemke

    2009-01-01

    Full Text Available We have developed a new technique for estimating ozone mixing ratio inside deep convective clouds. The technique uses the concept of an optical centroid cloud pressure that is indicative of the photon path inside clouds. Radiative transfer calculations based on realistic cloud vertical structure as provided by CloudSat radar data show that because deep convective clouds are optically thin near the top, photons can penetrate significantly inside the cloud. This photon penetration coupled with in-cloud scattering produces optical centroid pressures that are hundreds of hPa inside the cloud. We combine measured column ozone and the optical centroid cloud pressure derived using the effects of rotational-Raman scattering to estimate O3 mixing ratio in the upper regions of deep convective clouds. The data are obtained from the Ozone Monitoring Instrument (OMI onboard NASA's Aura satellite. Our results show that low O3 concentrations in these clouds are a common occurrence throughout much of the tropical Pacific. Ozonesonde measurements in the tropics following convective activity also show very low concentrations of O3 in the upper troposphere. These low amounts are attributed to vertical injection of ozone poor oceanic boundary layer air during convection into the upper troposphere followed by convective outflow. Over South America and Africa, O3 mixing ratios inside deep convective clouds often exceed 50 ppbv which are comparable to mean background (cloud-free amounts and are consistent with higher concentrations of injected boundary layer/lower tropospheric O3 relative to the remote Pacific. The Atlantic region in general also consists of higher amounts of O3 precursors due to both biomass burning and lightning. Assuming that O3 is well mixed (i.e., constant mixing ratio with height up to the tropopause, we can estimate the stratospheric column O3 over

  14. Ozone et propriétés oxydantes de la troposphère Ozone and Oxidizing Properties of the Troposhere

    Directory of Open Access Journals (Sweden)

    Académie des Sciences Groupe de Travail

    2006-11-01

    èles pertinents aux différentes échelles spatiales concernées. Up to now, the problem of the increase in ozone and photo-oxidants concentrations in the troposphere has remained less understood by decision-makers than that of the additional greenhouse effect or the decrease in the stratospheric ozone layer. Yet, the direct consequences of this increase concern the balance of plant ecosystems and the health of populations that are altered by the powerful oxidizing nature of this ozone as well as climatic balances, since ozone is a greenhouse-effect gas that is 1000 times more active than an equal concentration of carbon dioxide. On the global scale, experimental observations show that, since the start of the 20th century, the ozone level in the free atmosphere has been multiplied by 4 in the Northern hemisphere and by 2 in the Southern Hemisphere. This increase is the result of the direct production of ozone in the lower atmosphere by photochemical reactions, involving nitrogen oxides, volatile organic components, carbon monoxide and methane, the amount of which is increasing very fast as the result of anthropogenic activities. In addition to this increase on the global scale, there is also an increase in the frequency of the occurrence of local pollution episodes, linked mainly to the accumulation of ozone precursors, i. e. mainly nitrogen oxides and volatile organic compounds. Photochemical pollution phenomena are no longer solely the result of several large cities but are becoming prevalent in all the industrialized or developing countries. To cope with this fast increase, the present rate of which would lead to the doubling of the ozone concentrations in the troposphere in less than 40 years, regulatory measures are being set up in several countries, and particularly in the European Union. Respecting them will require the development of coherent strategies to reduce the precursors, based on models pertaining to the different spatial scales involved.

  15. VOC reactivity and its effect on ozone production during the HaChi summer campaign

    Directory of Open Access Journals (Sweden)

    L. Ran

    2011-05-01

    Full Text Available Measurements of ozone and its precursors conducted within the HaChi (Haze in China project in summer 2009 were analyzed to characterize volatile organic compounds (VOCs and their effects on ozone photochemical production at a suburban site in the North China Plain (NCP. Ozone episodes, during which running 8-h average ozone concentrations exceeding 80 ppbv lasted for more than 4 h, occurred on about two thirds of the observational days during the 5-week field campaign. This suggests continuous ozone exposure risks in this region in the summer. Average concentrations of nitrogen oxides (NOx and VOCs are about 20 ppbv and 650 ppbC, respectively. On average, total VOC reactivity is dominated by anthropogenic VOCs. The contribution of biogenic VOCs to total ozone-forming potential, however, is also considerable in the daytime. Key species associated with ozone photochemical production are 2-butenes (18 %, isoprene (15 %, trimethylbenzenes (11 %, xylenes (8.5 %, 3-methylhexane (6 %, n-hexane (5 % and toluene (4.5 %. Formation of ozone is found to be NOx-limited as indicated by measured VOCs/NOx ratios and further confirmed by a sensitivity study using a photochemical box model NCAR_MM. The Model simulation suggests that ozone production is also sensitive to changes in VOC reactivity under the NOx-limited regime, although this sensitivity depends strongly on how much NOx is present.

  16. Impact of climate change on ozone-related mortality and morbidity in Europe.

    Science.gov (United States)

    Orru, Hans; Andersson, Camilla; Ebi, Kristie L; Langner, Joakim; Aström, Christofer; Forsberg, Bertil

    2013-02-01

    Ozone is a highly oxidative pollutant formed from precursors in the presence of sunlight, associated with respiratory morbidity and mortality. All else being equal, concentrations of ground-level ozone are expected to increase due to climate change. Ozone-related health impacts under a changing climate are projected using emission scenarios, models and epidemiological data. European ozone concentrations are modelled with the model of atmospheric transport and chemistry (MATCH)-RCA3 (50×50 km). Projections from two climate models, ECHAM4 and HadCM3, are applied under greenhouse gas emission scenarios A2 and A1B, respectively. We applied a European-wide exposure-response function to gridded population data and country-specific baseline mortality and morbidity. Comparing the current situation (1990-2009) with the baseline period (1961-1990), the largest increase in ozone-associated mortality and morbidity due to climate change (4-5%) have occurred in Belgium, Ireland, the Netherlands and the UK. Comparing the baseline period and the future periods (2021-2050 and 2041-2060), much larger increases in ozone-related mortality and morbidity are projected for Belgium, France, Spain and Portugal, with the impact being stronger using the climate projection from ECHAM4 (A2). However, in Nordic and Baltic countries the same magnitude of decrease is projected. The current study suggests that projected effects of climate change on ozone concentrations could differentially influence mortality and morbidity across Europe.

  17. The impact of temperature changes on summer time ozone and its precursors in the Eastern Mediterranean

    Directory of Open Access Journals (Sweden)

    U. Im

    2011-04-01

    Full Text Available Changes in temperature due to variability in meteorology and climate change are expected to significantly impact atmospheric composition. The Mediterranean is a climate sensitive region and includes megacities like Istanbul and large urban agglomerations such as Athens. The effect of temperature changes on gaseous air pollutant levels and the atmospheric processes that are controlling them in the Eastern Mediterranean are here investigated. The WRF/CMAQ mesoscale modeling system is used, coupled with the MEGAN model for the processing of biogenic volatile organic compound emissions. A set of temperature perturbations (spanning from 1 to 5 K is applied on a base case simulation corresponding to July 2004. The results indicate that the Eastern Mediterranean basin acts as a reservoir of pollutants and their precursor emissions from large urban agglomerations. During summer, chemistry is a major sink at these urban areas near the surface, and a minor contributor at downwind areas. On average, the atmospheric processes are more effective within the first 1000 m above ground. Temperature increases lead to increases in biogenic emissions by 9±3% K−1. Ozone mixing ratios increase almost linearly with the increases in ambient temperatures by 1±0.1 ppb O3 K−1 for all studied urban and receptor stations except for Istanbul, where a 0.4±0.1 ppb O3 K−1 increase is calculated, which is about half of the domain-averaged increase of 0.9±0.1 ppb O3 K−1. The computed changes in atmospheric processes are also linearly related with temperature changes.

  18. Ozone-surface interactions: Investigations of mechanisms, kinetics, mass transport, and implications for indoor air quality

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, Glenn Charles [Univ. of California, Berkeley, CA (United States)

    1999-12-01

    In this dissertation, results are presented of laboratory investigations and mathematical modeling efforts designed to better understand the interactions of ozone with surfaces. In the laboratory, carpet and duct materials were exposed to ozone and measured ozone uptake kinetics and the ozone induced emissions of volatile organic compounds. To understand the results of the experiments, mathematical methods were developed to describe dynamic indoor aldehyde concentrations, mass transport of reactive species to smooth surfaces, the equivalent reaction probability of whole carpet due to the surface reactivity of fibers and carpet backing, and ozone aging of surfaces. Carpets, separated carpet fibers, and separated carpet backing all tended to release aldehydes when exposed to ozone. Secondary emissions were mostly n-nonanal and several other smaller aldehydes. The pattern of emissions suggested that vegetable oils may be precursors for these oxidized emissions. Several possible precursors and experiments in which linseed and tung oils were tested for their secondary emission potential were discussed. Dynamic emission rates of 2-nonenal from a residential carpet may indicate that intermediate species in the oxidation of conjugated olefins can significantly delay aldehyde emissions and act as reservoir for these compounds. The ozone induced emission rate of 2-nonenal, a very odorous compound, can result in odorous indoor concentrations for several years. Surface ozone reactivity is a key parameter in determining the flux of ozone to a surface, is parameterized by the reaction probability, which is simply the probability that an ozone molecule will be irreversibly consumed when it strikes a surface. In laboratory studies of two residential and two commercial carpets, the ozone reaction probability for carpet fibers, carpet backing and the equivalent reaction probability for whole carpet were determined. Typically reaction probability values for these materials were 10

  19. ESA CAMELOT study: Challenges in future operational missions for GMES atmospheric monitoring, sentinel 4 and 5

    Science.gov (United States)

    Levelt, P.; Veefkind, P.

    2009-04-01

    Dedicated atmospheric chemistry observations from space have been made for over 30 years now, starting with the SBUV and TOMS measurements of the ozone layer. Since then huge progress has been made, improving the accuracy of the measurements, extending the amount of constituents, and by sensing not only the stratosphere, but the last five to ten years also the troposphere. The potential to operational monitor the atmosphere, following the meteorological community, came within reach. At the same time, the importance for society of regular operational environmental measurements, related to the ozone layer, air quality and climate change, became apparent, amongst others resulting in the EU initiative Global Monitoring for Environment and Security (GMES) In order to prepare the operational missions in the context of the GMES, ESA took the initiative to further study the user requirements for the Sentinel 4 and 5 (precursor) missions. The Sentinel 4 and 5 (precursor) missions are dedicated operational missions to monitor the atmospheric composition in the 2013-2020 timeframe and onward. The user requirements for the sentinel missions focus on monitoring the atmosphere from an environmental point of view (ozone layer, air quality and climate). ESA's CAMELOT (Composition of the Atmospheric Mission concEpts and SentineL Observation Techniques) study is the follow-on study to ESA's CAPACITY study finished in 2005. The general objective of the CAMELOT study is to further contribute to the definition of the air quality and climate protocol monitoring parts of the GMES Sentinel 4 and 5 missions. Key issues in the CAMELOT study are: • trade-offs between different observation strategies (spectral ranges, polarisation, direction etc) for aerosols and several trace gases • a quantitative assessment of the requirements for spatio-temporal sampling taking into account the contamination of nadir-viewing observations by cloud • optimising several orbit scenario's (leo, inclined

  20. Future local and remote influences on Mediterranean ozone air quality and climate forcing

    Science.gov (United States)

    Arnold, Steve; Martin, Maria Val; Emmons, Louisa; Rap, Alex; Heald, Colette; Lamarque, Jean-Francois; Tilmes, Simone

    2013-04-01

    under both RCP scenarios, and a significant increase in ozone between 5-10km. Using tagged regional NOy and tropospheric ozone tracers, we show that this ozone increase is coincident with an increase in easterly import of ozone and precursors in upper tropospheric outflow from Asian monsoon convection in 2050. We present a breakdown of the projected Mediterranean ozone changes by precursor source (anthropogenic and biogenic), and contributions due to changes in climate. Finally, we estimate the implications of the predicted changes in tropospheric composition for Mediterranean air quality and climate in 2050, and the consequences for the effectiveness of European policies aimed at protecting the region's climate and public health.

  1. Significant increase of surface ozone at a rural site, north of eastern China

    Directory of Open Access Journals (Sweden)

    Z. Ma

    2016-03-01

    Full Text Available Ozone pollution in eastern China has become one of the top environmental issues. Quantifying the temporal trend of surface ozone helps to assess the impacts of the anthropogenic precursor reductions and the likely effects of emission control strategies implemented. In this paper, ozone data collected at the Shangdianzi (SDZ regional atmospheric background station from 2003 to 2015 are presented and analyzed to obtain the variation in the trend of surface ozone in the most polluted region of China, north of eastern China or the North China Plain. A modified Kolmogorov–Zurbenko (KZ filter method was performed on the maximum daily average 8 h (MDA8 concentrations of ozone to separate the contributions of different factors from the variation of surface ozone and remove the influence of meteorological fluctuations on surface ozone. Results reveal that the short-term, seasonal and long-term components of ozone account for 36.4, 57.6 and 2.2 % of the total variance, respectively. The long-term trend indicates that the MDA8 has undergone a significant increase in the period of 2003–2015, with an average rate of 1.13 ± 0.01 ppb year−1 (R2 = 0.92. It is found that meteorological factors did not significantly influence the long-term variation of ozone and the increase may be completely attributed to changes in emissions. Furthermore, there is no significant correlation between the long-term O3 and NO2 trends. This study suggests that emission changes in VOCs might have played a more important role in the observed increase of surface ozone at SDZ.

  2. Ozone-mist spray sterilization for pest control in agricultural management

    Science.gov (United States)

    Ebihara, Kenji; Mitsugi, Fumiaki; Ikegami, Tomoaki; Nakamura, Norihito; Hashimoto, Yukio; Yamashita, Yoshitaka; Baba, Seiji; Stryczewska, Henryka D.; Pawlat, Joanna; Teii, Shinriki; Sung, Ta-Lun

    2013-02-01

    We developed a portable ozone-mist sterilization system to exterminate pests (harmful insects) in agricultural field and greenhouse. The system is composed of an ozone generator, an ozone-mist spray and a small container of ozone gas. The ozone generator can supply highly concentrated ozone using the surface dielectric barrier discharge. Ozone-mist is produced using a developed nozzle system. We studied the effects of ozone-mist spray sterilization on insects and agricultural plants. The sterilization conditions are estimated by monitoring the behavior of aphids and observing the damage of the plants. It was shown that aphids were exterminated in 30 s without noticeable damages of the plant leaves. The reactive radicals with strong oxidation potential such as hydroxyl radical (*OH), hydroperoxide radical (*HO2), the superoxide ion radical (*O2‒) and ozonide radical ion (*O3‒) can increase the sterilization rate for aphids. Contribution to the Topical Issue "13th International Symposium on High Pressure Low Temperature Plasma Chemistry (Hakone XIII)", Edited by Nicolas Gherardi, Henryca Danuta Stryczewska and Yvan Ségui.

  3. Relationship between surface, free tropospheric and total column ozone in 2 contrasting areas in South-Africa

    CSIR Research Space (South Africa)

    Combrink, J

    1995-04-01

    Full Text Available Measurements of surface ozone in two contrasting areas of South Africa are compared with free tropospheric and Total Ozone Mapping Spectrometer (TOMS) total column ozone data. Cape Point is representative of a background monitoring station which...

  4. Monitoring ambient ozone with a passive measurement technique method, field results and strategy

    NARCIS (Netherlands)

    Scheeren, BA; Adema, EH

    1996-01-01

    A low-cost, accurate and sensitive passive measurement method for ozone has been developed and tested. The method is based on the reaction of ozone with indigo carmine which results in colourless reaction products which are detected spectrophotometrically after exposure. Coated glass filters are

  5. Process-scale modeling of elevated wintertime ozone in Wyoming.

    Energy Technology Data Exchange (ETDEWEB)

    Kotamarthi, V. R.; Holdridge, D. J.; Environmental Science Division

    2007-12-31

    Measurements of meteorological variables and trace gas concentrations, provided by the Wyoming Department of Environmental Quality for Daniel, Jonah, and Boulder Counties in the state of Wyoming, were analyzed for this project. The data indicate that highest ozone concentrations were observed at temperatures of -10 C to 0 C, at low wind speeds of about 5 mph. The median values for nitrogen oxides (NOx) during these episodes ranged between 10 ppbv and 20 ppbv (parts per billion by volume). Measurements of volatile organic compounds (VOCs) during these periods were insufficient for quantitative analysis. The few available VOCs measurements indicated unusually high levels of alkanes and aromatics and low levels of alkenes. In addition, the column ozone concentration during one of the high-ozone episodes was low, on the order of 250 DU (Dobson unit) as compared to a normal column ozone concentration of approximately 300-325 DU during spring for this region. Analysis of this observation was outside the scope of this project. The data analysis reported here was used to establish criteria for making a large number of sensitivity calculations through use of a box photochemical model. Two different VOCs lumping schemes, RACM and SAPRC-98, were used for the calculations. Calculations based on this data analysis indicated that the ozone mixing ratios are sensitive to (a) surface albedo, (b) column ozone, (c) NOx mixing ratios, and (d) available terminal olefins. The RACM model showed a large response to an increase in lumped species containing propane that was not reproduced by the SAPRC scheme, which models propane as a nearly independent species. The rest of the VOCs produced similar changes in ozone in both schemes. In general, if one assumes that measured VOCs are fairly representative of the conditions at these locations, sufficient precursors might be available to produce ozone in the range of 60-80 ppbv under the conditions modeled.

  6. Occurrence of ozone anomalies over cloudy areas in TOMS version-7 level-2 data

    Directory of Open Access Journals (Sweden)

    X. Liu

    2003-01-01

    because of rich ozone precursors and higher photolysis rates over high-frequency, low-altitude clouds than in clear areas. Ozone anomalies due to ozone retrieval errors have important implications in TOMS applications such as tropospheric ozone derivation and analysis of ozone seasonal variation.

  7. Degradation of the ammonia wastewater in aqueous medium with ozone in combination with mesoporous TiO2 catalytic

    Science.gov (United States)

    Liu, Zhiwu; Qiu, Jianping; Zheng, Chaocan; Li, Liqing

    2017-03-01

    TiO2 mesoporous nanomaterials are now widely used in catalytic ozone technology. In this paper, the market P25 as precursor hydrothermal method to prepare TiO2 mesoporous materials, ozone catalyst material characterization by transmission electron microscopy, surface area analyzers, and X-ray diffraction technique and found that nanotubes, nanosheets, nanorods through characterization results, nano-particles of different morphology and anatase and rutile proportion of the ozone catalytic material can be controlled by the calcination temperature and the temperature of hot water to give, and with the hot water temperature and calcination temperature, the catalyst becomes small aperture size larger catalyst crystalline phase from anatase to rutile gradually shift. Catalytic materials have been prepared by the Joint ozone degradation of ammonia wastewater to evaluate mesoporous TiO2 nanomaterials ozone catalytic performance, the results showed that: ammonia wastewater removal efficiency of various catalytic materials relatively separate ozone and markets P25 effects are significantly improved, and TiO2 nanotubes cooperate with ozone degradation ammonia wastewater highest efficiency, in addition, rutile TiO2 catalysts, the more the better the performance of their ozone catalysis.

  8. Dependence of Ozone Generation on Gas Temperature Distribution in AC Atmospheric Pressure Dielectric Barrier Discharge in Oxygen

    Science.gov (United States)

    Takahashi, Go; Akashi, Haruaki

    AC atmospheric pressure multi-filament dielectric barrier discharge in oxygen has been simulated using two dimensional fluid model. In the discharge, three kinds of streamers have been obtained. They are primary streamers, small scale streamers and secondary streamers. The primary streamers are main streamers in the discharge and the small scale streamers are formed after the ceasing of the primary streamers. And the secondary streamers are formed on the trace of the primary streamers. In these streamers, the primary and the small scale streamers are very effective to generate O(3P) oxygen atoms which are precursor of ozone. And the ozone is generated mainly in the vicinity of the dielectrics. In high gas temperature region, ozone generation decreases in general. However, increase of the O(3P) oxygen atom density in high gas temperature region compensates decrease of ozone generation rate coefficient. As a result, amount of ozone generation has not changed. But if the effect of gas temperature was neglected, amount of ozone generation increases 10%.

  9. NOAA JPSS Ozone Mapping and Profiler Suite (OMPS) Nadir Profile Science Sensor Data Record (SDR) from IDPS

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Ozone Mapping and Profiler Suite (OMPS) onboard the Suomi-NPP satellite monitors ozone from space. OMPS will collect total column and vertical profile ozone data...

  10. NOAA JPSS Ozone Mapping and Profiler Suite (OMPS) Nadir Total Column Sensor Data Record (SDR) from IDPS

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Ozone Mapping and Profiler Suite (OMPS) onboard the Suomi NPP satellite monitors ozone from space. OMPS will collect total column and vertical profile ozone data...

  11. Photochemically consumed hydrocarbons and their relationship with ozone formation in two megacities of China

    Science.gov (United States)

    Chang, C.; Wang, J.; Liu, S.; Shao, M.; Zhang, Y.; Zhu, T.; Shiu, C.; Lai, C.

    2010-12-01

    Two on-site continuous measurements of ozone and its precursors in two megacities of China were carried out in an urban site of Beijing and a suburban site near Guangzhou in the Pearl River Delta (PRD) to estimate precursor consumption and to assess its relationship with oxidant (O3+NO2) formation level. An observation-based method (OBM) with the precursor consumption concept was adopted to assess the relationship between oxidant production and amounts of photochemically consumed non-methane hydrocarbons (NMHCs). In this approach, the ratio of ethylbenzene to m,p-xylenes was used to estimate the degree of photochemical processing, as well as the amounts of photochemically consumed NMHCs by reacting with OH. By trying to correlate the observed oxidant with the observed NMHC concentration, the two areas both revealed nearly no to low correlation between them. However, it existed fair to good correlations (R2=0.68 for Beijing, 0.53 for PRD) between the observed oxidant level and the degree of photochemical processing (ethylbenzene/m,p-xylenes). Furthermore, after taking the approach of consumption to estimate the consumed amounts of NMHCs, an interesting finding reveals that the definite correlation existed between the observed oxidant level and the total consumed NMHCs. The good correlations (R2=0.83 for Beijing, 0.81 for PRD) implies that the ambient oxidant level correlated to the amount of consumed NMHCs. The results of the two megacities in China by using the OBM with the precursor consumption concept can provide another pathway to explore the relationship between photochemically produced oxidant and consumed precursors, and will be helpful to validate model results and to reduce uncertainty of model predictions. However, the method has some room for uncertainty, as injection of fresh precursor emissions and additional boundary ozone involved, etc. could affect the estimation of consumed NMHCs and observed oxidant levels. Assistance of approaches in assessing the

  12. Experimental effect of ozone upon the microbial flora of commercially produced dairy fermented products.

    Science.gov (United States)

    Alexopoulos, A; Plessas, S; Kourkoutas, Y; Stefanis, C; Vavias, S; Voidarou, C; Mantzourani, I; Bezirtzoglou, E

    2017-04-04

    Ozone was used to control spoilage microorganisms during the manufacturing of dairy products. Ozone stream was applied onto the surface of freshly filled yoghurt cups just before storage for curd development in order to prevent cross contamination from spoilage airborne microorganisms. Accordingly, brine solution was bubbled with ozone for various periods of time and used for ripening of white (feta type) cheese. Both products were subjected to a continuous monitoring of microbial load and also tested for their sensorial properties. In ozonated yoghurt samples there was a reduction in mould counts of approximately 0.6Logcfu/g (25.1%) by the end of the monitoring period in relation to the control samples. In white cheese ripened with ozonated brine (1.3mg/L O 3 , NaCl 5%) it seems that ozone treatment during the two months of observation reduced some of the mould load but without offering any advantages over the use of traditional brine (NaCl 7%). However, some sensorial alterations were observed, probably due to the organic load in the brine which deactivates ozone in early stages of application. It is concluded that, if the factors of time and concentration of ozone are configured properly, ozonation could be a promising approach safeguarding the production of some dairy products. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Detecting the Recovery of the Antarctic Ozone Hole

    Science.gov (United States)

    Newman, Paul A.; Nash, Eric R.; Kawa, S. Randolph; Montzka, Steve

    2004-01-01

    The Antarctic ozone hole develops each year and culminates by early Spring. Antarctic ozone values have been monitored since 1979 using satellite observations from the TOMS instrument. The severity of the hole has been assessed from TOMS using the minimum total ozone value from the October monthly mean (depth of the hole) and by calculating the average size during the September-October period. Ozone is mainly destroyed by halogen catalytic cycles, and these losses are modulated by temperature variations in the collar of the polar lower stratospheric vortex. In this presentation, we show the relationships of halogens and temperature to both the size and depth of the hole. Because atmospheric halogen levels are responding to international agreements that limit or phase out production, the amount of halogens in the stratosphere should decrease over the next few decades. Using projections of halogen levels combined with age-of-air estimates, we find that the ozone hole is recovering at an extremely slow rate and that large ozone holes will regularly recur over the next 2 decades. We will show estimates of both when the ozone hole will begin to show first signs of recovery, and when the hole will fully recover to pre-1980 levels.

  14. Ground-level ozone pollution and its health impacts in China

    Science.gov (United States)

    Liu, Huan; Liu, Shuai; Xue, Boru; Lv, Zhaofeng; Meng, Zhihang; Yang, Xiaofan; Xue, Tao; Yu, Qiao; He, Kebin

    2018-01-01

    In recent years, ground-level ozone pollution in China has become an increasingly prominent problem. This study simulated and analyzed spatiotemporal distribution of ozone and exposure level by the Weather Research and Forecasting (WRF)-Community Multiscale Air Quality (CMAQ) models and monitoring data from 1516 national air quality monitoring stations in China during 2015. The simulation results show that the Sichuan Basin, Shandong, Shanxi, Henan, Anhui, Qinghai-Tibetan Plateau, Yangtze River Delta (YRD), Pearl River Delta (PRD) and Beijing-Tianjin-Hebei (BTH) region had relatively high average annual concentrations of ozone. The regions with more than 10% nonattainment days of 160 μg/m3 (daily maximum 8-h) are mainly concentrated in BTH, Shandong Peninsula and YRD, where large seasonal variations were also found. Exposure levels were calculated based on population data and simulated ozone concentrations. The cumulative population exposed to daily maximum 8-h concentration greater than or equal to 100 μg/m3 was 816.04 million, 61.17% of the total. Three methods were used to estimate the mortality of chronic obstructive pulmonary disease (COPD) attributable to ozone. A comparative study using different exposure concentrations and threshold concentrations found large variations among these methods, although they were all peer-reviewed methods. The estimated mortality of COPD caused by ozone in China in 2015 ranged from 55341 to 80280, which mainly distributed in Beijing, Shandong, Henan, Hubei and Sichuan Province, the YRD and PRD region.

  15. Spatial and temporal variation of surface ozone, NO and NO₂ at urban, suburban, rural and industrial sites in the southwest of the Iberian Peninsula.

    Science.gov (United States)

    Domínguez-López, D; Adame, J A; Hernández-Ceballos, M A; Vaca, F; De la Morena, B A; Bolívar, J P

    2014-09-01

    Surface ozone is one of the most important photochemical pollutants in the low atmosphere, causing damage to human health, vegetation, materials and climate. The weather (high temperatures and high solar radiation), orography (presence of the Guadalquivir valley) and anthropogenic (the cities of Cádiz, Córdoba, Huelva and Seville and two important industrial complexes) characteristics of the southwestern Iberian Peninsula make this region ideal for the formation and accumulation of ozone. To increase the knowledge of ozone behaviour in this area, the monthly, daily and weekly variations of ozone and its precursors, nitrogen oxides (NO(x) = NO + NO2), were analysed over a 4-year period (2003 to 2006). Using the k-means cluster technique, 12 representative stations of five different areas with different ozone behaviour were selected from a total of 29 monitoring sites. This is the first time that the analysis of these atmospheric pollutants has been carried out for the whole area, allowing therefore a complete understanding of the dynamics and the relationships of these compounds in this region. The results showed an opposite behaviour among ozone and NO and NO2 concentrations in urban and suburban zones, marked by maximums of ozone (minimums NO(x)) in spring and summer and minimums (maximums) in autumn and winter. A seasonal behaviour, with lower amplitude, was also observed in rural and industrial areas for ozone concentrations, with the NO and NO2 concentrations remaining at low and similar values during the year in rural zones due to the absence of emission sources in their surroundings. The daily cycles of ozone in urban, suburban and industrial sites registered a maximum value in the early afternoon (14:00-17:00 UTC) while for NOx two peaks were observed, at 7:00-10:00 UTC and 20:00-22:00. In the case of rural stations, no hourly peak of ozone or NO(x) was registered. The weekend effect was studied by using a statistical contrast tests (Student's t

  16. Simulation of summer ozone episodes in Southeast Louisiana during 2006-2015

    Science.gov (United States)

    Guo, H.; Zhang, H.

    2017-12-01

    Southeast Louisiana experiences high ozone (O3) events due to immense emissions from industrial and urban sources and unique meteorology conditions of high temperatures, intensive solar radiation and land-sea breeze circulation. The Community Multi-scale Air Quality (CMAQ) model with modified photochemical mechanism is used to investigate the contributions of regional transport to ozone (O3) and its precursors to Southeast Louisiana in summer months from 2006 to 2015. The meteorological and CMAQ model performance are validated. Spatial and temporal variations of O3 are investigated during summer episodes in 10 years. Contributions of different source types and regions to 1 hour O3 are also quantified. Changes in the contributions of different source types and regions are also obtained to help design intelligent control measures.

  17. Modelling and analysis of ozone concentration by artificial intelligent techniques for estimating air quality

    Science.gov (United States)

    Taylan, Osman

    2017-02-01

    High ozone concentration is an important cause of air pollution mainly due to its role in the greenhouse gas emission. Ozone is produced by photochemical processes which contain nitrogen oxides and volatile organic compounds in the lower atmospheric level. Therefore, monitoring and controlling the quality of air in the urban environment is very important due to the public health care. However, air quality prediction is a highly complex and non-linear process; usually several attributes have to be considered. Artificial intelligent (AI) techniques can be employed to monitor and evaluate the ozone concentration level. The aim of this study is to develop an Adaptive Neuro-Fuzzy inference approach (ANFIS) to determine the influence of peripheral factors on air quality and pollution which is an arising problem due to ozone level in Jeddah city. The concentration of ozone level was considered as a factor to predict the Air Quality (AQ) under the atmospheric conditions. Using Air Quality Standards of Saudi Arabia, ozone concentration level was modelled by employing certain factors such as; nitrogen oxide (NOx), atmospheric pressure, temperature, and relative humidity. Hence, an ANFIS model was developed to observe the ozone concentration level and the model performance was assessed by testing data obtained from the monitoring stations established by the General Authority of Meteorology and Environment Protection of Kingdom of Saudi Arabia. The outcomes of ANFIS model were re-assessed by fuzzy quality charts using quality specification and control limits based on US-EPA air quality standards. The results of present study show that the ANFIS model is a comprehensive approach for the estimation and assessment of ozone level and is a reliable approach to produce more genuine outcomes.

  18. Multi-year assimilation of IASI and MLS ozone retrievals: variability of tropospheric ozone over the tropics in response to ENSO

    Science.gov (United States)

    Peiro, Hélène; Emili, Emanuele; Cariolle, Daniel; Barret, Brice; Le Flochmoën, Eric

    2018-05-01

    The Infrared Atmospheric Sounder Instrument (IASI) allows global coverage with very high spatial resolution and its measurements are promising for long-term ozone monitoring. In this study, Microwave Limb Sounder (MLS) O3 profiles and IASI O3 partial columns (1013.25-345 hPa) are assimilated in a chemistry transport model to produce 6-hourly analyses of tropospheric ozone for 6 years (2008-2013). We have compared and evaluated the IASI-MLS analysis and the MLS analysis to assess the added value of IASI measurements. The global chemical transport model MOCAGE (MOdèle de Chimie Atmosphérique à Grande Echelle) has been used with a linear ozone chemistry scheme and meteorological forcing fields from ERA-Interim (ECMWF global reanalysis) with a horizontal resolution of 2° × 2° and 60 vertical levels. The MLS and IASI O3 retrievals have been assimilated with a 4-D variational algorithm to constrain stratospheric and tropospheric ozone respectively. The ozone analyses are validated against ozone soundings and tropospheric column ozone (TCO) from the OMI-MLS residual method. In addition, an Ozone ENSO Index (OEI) is computed from the analysis to validate the TCO variability during the ENSO events. We show that the assimilation of IASI reproduces the variability of tropospheric ozone well during the period under study. The variability deduced from the IASI-MLS analysis and the OMI-MLS measurements are similar for the period of study. The IASI-MLS analysis can reproduce the extreme oscillation of tropospheric ozone caused by ENSO events over the tropical Pacific Ocean, although a correction is required to reduce a constant bias present in the IASI-MLS analysis.

  19. The influence of European pollution on ozone in the Near East and northern Africa

    Directory of Open Access Journals (Sweden)

    B. N. Duncan

    2008-04-01

    Full Text Available We present a modeling study of the long-range transport of pollution from Europe, showing that European emissions regularly elevate surface ozone by as much as 20 ppbv in summer in northern Africa and the Near East. European emissions cause 50–150 additional violations per year (i.e. above those that would occur without European pollution of the European health standard for ozone (8-h average >120 μg/m3 or ~60 ppbv in northern Africa and the Near East. We estimate that European ozone pollution is responsible for 50 000 premature mortalities globally each year, of which the majority occurs outside of Europe itself, including 37% (19 000 in northern Africa and the Near East. Much of the pollution from Europe is exported southward at low altitudes in summer to the Mediterranean Sea, northern Africa and the Near East, regions with favorable photochemical environments for ozone production. Our results suggest that assessments of the human health benefits of reducing ozone precursor emissions in Europe should include effects outside of Europe, and that comprehensive planning to improve air quality in northern Africa and the Near East likely needs to address European emissions.

  20. The Influence of European Pollution on Ozone in the Near East and Northern Africa

    Science.gov (United States)

    Duncan, B. N.; West, J. J.; Yoshida, Y.; Fiore, A. M.; Ziemke, J. R.

    2008-01-01

    We present a modeling study of the long-range transport of pollution from Europe, showing that European emissions regularly elevate surface ozone by as much as 20 ppbv in summer in northern Africa and the Near East. European emissions cause 50-150 additional violations per year (i.e. above those that would occur without European pollution) of the European health standard for ozone (8-h average greater than 120 micrograms per cubic meters or approximately 60 ppbv) in northern Africa and the Near East. We estimate that European ozone pollution is responsible for 50 000 premature mortalities globally each year, of which the majority occurs outside of Europe itself, including 37% (19 000) in northern Africa and the Near East. Much of the pollution from Europe is exported southward at low altitudes in summer to the Mediterranean Sea, northern Africa and the Near East, regions with favorable photochemical environments for ozone production. Our results suggest that assessments of the human health benefits of reducing ozone precursor emissions in Europe should include effects outside of Europe, and that comprehensive planning to improve air quality in northern Africa and the Near East likely needs to address European emissions.

  1. Attribution and evolution of ozone from Asian wild fires using satellite and aircraft measurements during the ARCTAS campaign

    Directory of Open Access Journals (Sweden)

    R. Dupont

    2012-01-01

    Full Text Available We use ozone and carbon monoxide measurements from the Tropospheric Emission Spectrometer (TES, model estimates of Ozone, CO, and ozone pre-cursors from the Real-time Air Quality Modeling System (RAQMS, and data from the NASA DC8 aircraft to characterize the source and dynamical evolution of ozone and CO in Asian wildfire plumes during the spring ARCTAS campaign 2008. On the 19 April, NASA DC8 O3 and aerosol Differential Absorption Lidar (DIAL observed two biomass burning plumes originating from North-Western Asia (Kazakhstan and South-Eastern Asia (Thailand that advected eastward over the Pacific reaching North America in 10 to 12 days. Using both TES observations and RAQMS chemical analyses, we track the wildfire plumes from their source to the ARCTAS DC8 platform. In addition to photochemical production due to ozone pre-cursors, we find that exchange between the stratosphere and the troposphere is a major factor influencing O3 concentrations for both plumes. For example, the Kazakhstan and Siberian plumes at 55 degrees North is a region of significant springtime stratospheric/tropospheric exchange. Stratospheric air influences the Thailand plume after it is lofted to high altitudes via the Himalayas. Using comparisons of the model to the aircraft and satellite measurements, we estimate that the Kazakhstan plume is responsible for increases of O3 and CO mixing ratios by approximately 6.4 ppbv and 38 ppbv in the lower troposphere (height of 2 to 6 km, and the Thailand plume is responsible for increases of O3 and CO mixing ratios of approximately 11 ppbv and 71 ppbv in the upper troposphere (height of 8 to 12 km respectively. However, there are significant sources of uncertainty in these estimates that point to the need for future improvements in both model and satellite observations. For example, it is challenging to characterize the fraction of air parcels from the stratosphere versus those from the

  2. Effects of black carbon and boundary layer interaction on surface ozone in Nanjing, China

    Directory of Open Access Journals (Sweden)

    J. Gao

    2018-05-01

    Full Text Available As an important solar radiation absorbing aerosol, the effect of black carbon (BC on surface ozone, via reducing photolysis rate, has been widely discussed by offline model studies. However, BC–boundary layer (BL interactions also influence surface ozone. Using the online model simulations and process analysis, we demonstrate the significant impact of BC–BL interaction on surface ozone in Nanjing. The absorbing effect of BC heats the air above the BL and suppresses and delays the development of the BL, which eventually leads to a change in surface ozone via a change in the contributions from chemical and physical processes (photochemistry, vertical mixing and advection. For chemical processes, the suppression of the BL leads to large amounts of ozone precursors being confined below the BL which has an increased effect on ozone chemical production and offsets the decrease caused by the reduction of the photolysis rate, thus enhancing ozone chemical formation from 10:00 to 12:00 LT. Furthermore, changes in physical processes, especially the vertical mixing process, show a more significant influence on surface ozone. The weakened turbulence, caused by the suppressed BL, entrains much less ozone aloft down to the surface. Finally, summing-up the changes in the processes, surface ozone reduces before noon and the maximum reduction reaches 16.4 ppb at 12:00 LT. In the afternoon, the changes in chemical process are small which inconspicuously influence surface ozone. However, change in the vertical mixing process still influences surface ozone significantly. Due to the delayed development of the BL, there are obvious ozone gradients around the top of BL. Therefore, high concentrations of ozone aloft can still be entrained down to the surface which offsets the reduction of surface ozone. Comparing the changes in the processes, the change in vertical mixing plays the most important role in impacting surface ozone. Our results highlight the

  3. Effects of black carbon and boundary layer interaction on surface ozone in Nanjing, China

    Science.gov (United States)

    Gao, Jinhui; Zhu, Bin; Xiao, Hui; Kang, Hanqing; Pan, Chen; Wang, Dongdong; Wang, Honglei

    2018-05-01

    As an important solar radiation absorbing aerosol, the effect of black carbon (BC) on surface ozone, via reducing photolysis rate, has been widely discussed by offline model studies. However, BC-boundary layer (BL) interactions also influence surface ozone. Using the online model simulations and process analysis, we demonstrate the significant impact of BC-BL interaction on surface ozone in Nanjing. The absorbing effect of BC heats the air above the BL and suppresses and delays the development of the BL, which eventually leads to a change in surface ozone via a change in the contributions from chemical and physical processes (photochemistry, vertical mixing and advection). For chemical processes, the suppression of the BL leads to large amounts of ozone precursors being confined below the BL which has an increased effect on ozone chemical production and offsets the decrease caused by the reduction of the photolysis rate, thus enhancing ozone chemical formation from 10:00 to 12:00 LT. Furthermore, changes in physical processes, especially the vertical mixing process, show a more significant influence on surface ozone. The weakened turbulence, caused by the suppressed BL, entrains much less ozone aloft down to the surface. Finally, summing-up the changes in the processes, surface ozone reduces before noon and the maximum reduction reaches 16.4 ppb at 12:00 LT. In the afternoon, the changes in chemical process are small which inconspicuously influence surface ozone. However, change in the vertical mixing process still influences surface ozone significantly. Due to the delayed development of the BL, there are obvious ozone gradients around the top of BL. Therefore, high concentrations of ozone aloft can still be entrained down to the surface which offsets the reduction of surface ozone. Comparing the changes in the processes, the change in vertical mixing plays the most important role in impacting surface ozone. Our results highlight the great impacts BC

  4. Evaluating A Priori Ozone Profile Information Used in TEMPO Tropospheric Ozone Retrievals

    Science.gov (United States)

    Johnson, Matthew S.; Sullivan, John T.; Liu, Xiong; Newchurch, Mike; Kuang, Shi; McGee, Thomas J.; Langford, Andrew O'Neil; Senff, Christoph J.; Leblanc, Thierry; Berkoff, Timothy; hide

    2016-01-01

    Ozone (O3) is a greenhouse gas and toxic pollutant which plays a major role in air quality. Typically, monitoring of surface air quality and O3 mixing ratios is primarily conducted using in situ measurement networks. This is partially due to high-quality information related to air quality being limited from space-borne platforms due to coarse spatial resolution, limited temporal frequency, and minimal sensitivity to lower tropospheric and surface-level O3. The Tropospheric Emissions: Monitoring of Pollution (TEMPO) satellite is designed to address these limitations of current space-based platforms and to improve our ability to monitor North American air quality. TEMPO will provide hourly data of total column and vertical profiles of O3 with high spatial resolution to be used as a near-real-time air quality product. TEMPO O3 retrievals will apply the Smithsonian Astrophysical Observatory profile algorithm developed based on work from GOME, GOME-2, and OMI. This algorithm uses a priori O3 profile information from a climatological data-base developed from long-term ozone-sonde measurements (tropopause-based (TB) O3 climatology). It has been shown that satellite O3 retrievals are sensitive to a priori O3 profiles and covariance matrices. During this work we investigate the climatological data to be used in TEMPO algorithms (TB O3) and simulated data from the NASA GMAO Goddard Earth Observing System (GEOS-5) Forward Processing (FP) near-real-time (NRT) model products. These two data products will be evaluated with ground-based lidar data from the Tropospheric Ozone Lidar Network (TOLNet) at various locations of the US. This study evaluates the TB climatology, GEOS-5 climatology, and 3-hourly GEOS-5 data compared to lower tropospheric observations to demonstrate the accuracy of a priori information to potentially be used in TEMPO O3 algorithms. Here we present our initial analysis and the theoretical impact on TEMPO retrievals in the lower troposphere.

  5. Evaluating A Priori Ozone Profile Information Used in TEMPO Tropospheric Ozone Retrievals

    Science.gov (United States)

    Johnson, M. S.; Sullivan, J. T.; Liu, X.; Newchurch, M.; Kuang, S.; McGee, T. J.; Langford, A. O.; Senff, C. J.; Leblanc, T.; Berkoff, T.; Gronoff, G.; Chen, G.; Strawbridge, K. B.

    2016-12-01

    Ozone (O3) is a greenhouse gas and toxic pollutant which plays a major role in air quality. Typically, monitoring of surface air quality and O3 mixing ratios is primarily conducted using in situ measurement networks. This is partially due to high-quality information related to air quality being limited from space-borne platforms due to coarse spatial resolution, limited temporal frequency, and minimal sensitivity to lower tropospheric and surface-level O3. The Tropospheric Emissions: Monitoring of Pollution (TEMPO) satellite is designed to address these limitations of current space-based platforms and to improve our ability to monitor North American air quality. TEMPO will provide hourly data of total column and vertical profiles of O3 with high spatial resolution to be used as a near-real-time air quality product. TEMPO O3 retrievals will apply the Smithsonian Astrophysical Observatory profile algorithm developed based on work from GOME, GOME-2, and OMI. This algorithm uses a priori O3 profile information from a climatological data-base developed from long-term ozone-sonde measurements (tropopause-based (TB) O3 climatology). It has been shown that satellite O3 retrievals are sensitive to a priori O3 profiles and covariance matrices. During this work we investigate the climatological data to be used in TEMPO algorithms (TB O3) and simulated data from the NASA GMAO Goddard Earth Observing System (GEOS-5) Forward Processing (FP) near-real-time (NRT) model products. These two data products will be evaluated with ground-based lidar data from the Tropospheric Ozone Lidar Network (TOLNet) at various locations of the US. This study evaluates the TB climatology, GEOS-5 climatology, and 3-hourly GEOS-5 data compared to lower tropospheric observations to demonstrate the accuracy of a priori information to potentially be used in TEMPO O3 algorithms. Here we present our initial analysis and the theoretical impact on TEMPO retrievals in the lower troposphere.

  6. Optical monitoring of Disinfection By-product Precursors with Fluorescence Excitation-Emission Mapping (F-EEM): Practical Application Issues for Drinking, Waste and Reuse Water Industry

    Science.gov (United States)

    Gilmore, A. M.

    2012-12-01

    Drinking water, wastewater and reuse plants must deal with regulations associated with bacterial contamination and halogen disinfection procedures that can generate harmful disinfection by-products (DBPs) including trihalomethanes (THMs), haloacetic acids (HOAAs) and other compounds. The natural fluorescent chromophoric dissolved organic matter (CDOM) is regulated as the major DBP precursor. This study outlines the advantages and current limitations associated with optical monitoring of water treatment processes using tcontemporary Fluorescence Excitation-Emission Mapping (F-EEM). The F-EEM method coupled with practical peak indexing and multi-variate analyses is potentially superior in terms of cost, speed and sensitivity over conventional total organic carbon (TOC) meters and specific UV-absorbance (SUVA) measurements. Hence there is strong interest in developing revised environmental regulations around the F-EEM technique instruments which can incidentally simultaneously measure the SUVA and DOC parameters. Importantly, the F-EEM technique, compared to the single-point TOC and SUVA signals can resolve CDOM classes distinguishing those that strongly cause DBPs. The F-EEM DBP prediction method can be applied to surface water sources to evaluate DBP potential as a function of the point sources and reservoir depth profiles. It can also be applied in-line to rapidly adjust DOC removal processes including sedimentation-flocculation, microfiltration, reverse-osmosis, and ozonation. Limitations and interferences for F-EEMs are discussed including those common to SUVA and TOC in contrast to the advantages including that F-EEMs are less prone to interferences from inorganic carbon and metal contaminations and require little if any chemical preparation. In conclusion, the F-EEM method is discussed in terms of not only the DBP problem but also as a means of predicting (concurrent to DBP monitoring) organic membrane fouling in water-reuse and desalination plants.

  7. Interpretation of ozone vertical profiles and their variations in the Northern hemisphere on the basis of GOME satellite data. Final report; Interpretation von Ozon-Vertikalprofilen und deren Variationen in der noerdlichen Hemisphaere unter Benutzung von GOME Satellitendaten. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Eichmann, K.U.; Bramstedt, K.; Weber, M.; Rozanov, V.; Debeek, R.; Hoogen, R.; Burrows, J.P.

    2000-07-04

    Semiglobal ozone vertical profiles based on GOME measurements were established and evaluated systematically. GOME (Global Ozone Monitoring Experiment), carried by the ERS-2 satellite, is the first European passive optical sensor for long-term monitoring of ozone, other trace elements, and aerosols. Especially the vertical distribution of ozone in the Arctic region was measured and interpreted with a view to enhanced ozone degradation in the Arctic winter and spring seasons. Apart from the regional variations, also the time variations of the profiles are to provide further information on the dynamics and chemical processes in the polar vortex. The retrieval algorithm used for assessing the ozone vertical profiles, FURM (FUll Retrieval Method), is based on the GOMETRAN radiation transport model developed at Bremen university especially for evaluation of the GOME data. The GOME ozone profiles were validated with ozone probes and other satellite experiments. [German] Ziel des Projektes war eine systematische Bestimmung und Auswertung von semiglobalen Ozonvertikalprofilen aus den Messdaten von GOME. Das auf dem Satelliten ERS-2 fliegende Spektrometer GOME (Global Ozone Monitoring Experiment) ist der erste europaeische, passive, optische Sensor, der fuer Langzeitmessungen von Ozon, anderen Spurenstoffen und Aerosolen konzipiert wurde. Im Projekt wurde insbesondere die vertikale Verteilung von Ozon in der Arktis bestimmt und interpretiert hinsichtlich des verstaerkten Ozonabbaus im arktischen Winter und Fruehjahr. Neben der raeumlichen Variation sollen auch die zeitlichen Ablaeufe und Veraenderungen der Profile weitere Erkenntnise hinsichtlich der Dynamik und der chemischen Prozesse im Polarwirbel liefern. Der Retrievalalgorithmus zur Bestimmung des Ozonhoehenprofils, FURM (Full Retrieval Method) genannt, basiert auf dem Strahlungstransportmodell GOMETRAN, das an der Universitaet Bremen speziell fuer die Auswertung der Daten des GOME Instrumentes entwickelt wurde

  8. Statistical evaluation of the impact of shale gas activities on ozone pollution in North Texas.

    Science.gov (United States)

    Ahmadi, Mahdi; John, Kuruvilla

    2015-12-01

    Over the past decade, substantial growth in shale gas exploration and production across the US has changed the country's energy outlook. Beyond its economic benefits, the negative impacts of shale gas development on air and water are less well known. In this study the relationship between shale gas activities and ground-level ozone pollution was statistically evaluated. The Dallas-Fort Worth (DFW) area in north-central Texas was selected as the study region. The Barnett Shale, which is one the most productive and fastest growing shale gas fields in the US, is located in the western half of DFW. Hourly meteorological and ozone data were acquired for fourteen years from monitoring stations established and operated by the Texas Commission on Environmental Quality (TCEQ). The area was divided into two regions, the shale gas region (SGR) and the non-shale gas (NSGR) region, according to the number of gas wells in close proximity to each monitoring site. The study period was also divided into 2000-2006 and 2007-2013 because the western half of DFW has experienced significant growth in shale gas activities since 2007. An evaluation of the raw ozone data showed that, while the overall trend in the ozone concentration was down over the entire region, the monitoring sites in the NSGR showed an additional reduction of 4% in the annual number of ozone exceedance days than those in the SGR. Directional analysis of ozone showed that the winds blowing from areas with high shale gas activities contributed to higher ozone downwind. KZ-filtering method and linear regression techniques were used to remove the effects of meteorological variations on ozone and to construct long-term and short-term meteorologically adjusted (M.A.) ozone time series. The mean value of all M.A. ozone components was 8% higher in the sites located within the SGR than in the NSGR. These findings may be useful for understanding the overall impact of shale gas activities on the local and regional ozone

  9. Passive sampling of ambient ozone by solid phase microextraction with on-fiber derivatization

    International Nuclear Information System (INIS)

    Lee, I-S.; Tsai, S.-W.

    2008-01-01

    The solid phase microextraction (SPME) device with the polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber was used as a passive sampler for ambient ozone. Both O-2,3,4,5,6-(pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) and 1,2-di-(4-pyridyl)ethylene (DPE) were loaded onto the fiber before sampling. The SPME fiber assembly was then inserted into a PTFE tubing as a passive sampler. Known concentrations of ozone around the ambient ground level were generated by a calibrated ozone generator. Laboratory validations of the SPME passive sampler with the direct-reading ozone monitor were performed side-by-side in an exposure chamber at 25 deg. C. After exposures, pyriden-4-aldehyde was formed due to the reaction between DPE and ozone. Further on-fiber derivatizations between pyriden-4-aldehyde and PFBHA were followed and the derivatives, oximes, were then determined by portable gas chromatography with electron capture detector. The experimental sampling rate of the SPME ozone passive sampler was found to be 1.10 x 10 -4 cm 3 s -1 with detection limit of 58.8 μg m -3 h -1 . Field validations with both SPME device and the direct-reading ozone monitor were also performed. The correlations between the results from both methods were found to be consistent with r = 0.9837. Compared with other methods, the current designed sampler provides a convenient and sensitive tool for the exposure assessments of ozone

  10. Use of bioindicators and passive sampling devices to evaluate ambient ozone concentrations in north central Pennsylvania

    Energy Technology Data Exchange (ETDEWEB)

    Yuska, D.E.; Skelly, J.M.; Ferdinand, J.A.; Stevenson, R.E.; Savage, J.E.; Mulik, J.D.; Hines, A

    2003-09-01

    Passive samplers and bioindicator plants detect ozone air pollution in north central Pennsylvania. - Ambient concentrations of tropospheric ozone and ozone-induced injury to black cherry (Prunus serotina) and common milkweed (Asclepias syriaca) were determined in north central Pennsylvania from 29 May to 5 September 2000 and from 28 May to 18 September 2001. Ogawa passive ozone samplers were utilized within openings at 15 forested sites of which six were co-located with TECO model 49 continuous ozone monitors. A significant positive correlation was observed between the Ogawa passive samplers and the TECO model 49 continuous ozone monitors for the 2000 (r=0.959) and 2001 (r=0.979) seasons. In addition, a significant positive correlation existed in 2000 and 2001 between ozone concentration and elevation (r=0.720) and (r=0.802), respectively. Classic ozone-induced symptoms were observed on black cherry and common milkweed. In 2000, initial injury was observed in early June, whereas for the 2001 season, initial injury was initially observed in late June. During both seasons, injury was noted at most sites by mid- to late-July. Soil moisture potential was measured for the 2001 season and a significant positive relationship (P<0.001) showed that injury to black cherry was a function of cumulative ozone concentrations and available soil moisture.

  11. Use of bioindicators and passive sampling devices to evaluate ambient ozone concentrations in north central Pennsylvania

    International Nuclear Information System (INIS)

    Yuska, D.E.; Skelly, J.M.; Ferdinand, J.A.; Stevenson, R.E.; Savage, J.E.; Mulik, J.D.; Hines, A.

    2003-01-01

    Passive samplers and bioindicator plants detect ozone air pollution in north central Pennsylvania. - Ambient concentrations of tropospheric ozone and ozone-induced injury to black cherry (Prunus serotina) and common milkweed (Asclepias syriaca) were determined in north central Pennsylvania from 29 May to 5 September 2000 and from 28 May to 18 September 2001. Ogawa passive ozone samplers were utilized within openings at 15 forested sites of which six were co-located with TECO model 49 continuous ozone monitors. A significant positive correlation was observed between the Ogawa passive samplers and the TECO model 49 continuous ozone monitors for the 2000 (r=0.959) and 2001 (r=0.979) seasons. In addition, a significant positive correlation existed in 2000 and 2001 between ozone concentration and elevation (r=0.720) and (r=0.802), respectively. Classic ozone-induced symptoms were observed on black cherry and common milkweed. In 2000, initial injury was observed in early June, whereas for the 2001 season, initial injury was initially observed in late June. During both seasons, injury was noted at most sites by mid- to late-July. Soil moisture potential was measured for the 2001 season and a significant positive relationship (P<0.001) showed that injury to black cherry was a function of cumulative ozone concentrations and available soil moisture

  12. Development of a climate record of tropospheric and stratospheric column ozone from satellite remote sensing: evidence of an early recovery of global stratospheric ozone

    Directory of Open Access Journals (Sweden)

    J. R. Ziemke

    2012-07-01

    Full Text Available Ozone data beginning October 2004 from the Aura Ozone Monitoring Instrument (OMI and Aura Microwave Limb Sounder (MLS are used to evaluate the accuracy of the Cloud Slicing technique in effort to develop long data records of tropospheric and stratospheric ozone and for studying their long-term changes. Using this technique, we have produced a 32-yr (1979–2010 long record of tropospheric and stratospheric column ozone from the combined Total Ozone Mapping Spectrometer (TOMS and OMI. Analyses of these time series suggest that the quasi-biennial oscillation (QBO is the dominant source of inter-annual variability of stratospheric ozone and is clearest in the Southern Hemisphere during the Aura time record with related inter-annual changes of 30–40 Dobson Units. Tropospheric ozone for the long record also indicates a QBO signal in the tropics with peak-to-peak changes varying from 2 to 7 DU. The most important result from our study is that global stratospheric ozone indicates signature of a recovery occurring with ozone abundance now approaching the levels of year 1980 and earlier. The negative trends in stratospheric ozone in both hemispheres during the first 15 yr of the record are now positive over the last 15 yr and with nearly equal magnitudes. This turnaround in stratospheric ozone loss is occurring about 20 yr earlier than predicted by many chemistry climate models. This suggests that the Montreal Protocol which was first signed in 1987 as an international agreement to reduce ozone destroying substances is working well and perhaps better than anticipated.

  13. Studies on calibration and validation of data provided by the Global Ozone Monitoring Experiment GOME on ERS-2 (CAVEAT). Final report; Studie zur Kalibrierung und Validation von Daten des Global Ozone Monitoring Experiments GOME auf ERS-2 (CAVEAT). Endbericht

    Energy Technology Data Exchange (ETDEWEB)

    Burrows, J.P.; Kuenzi, K.; Ladstaetter-Weissenmayer, A.; Langer, J. [Bremen Univ. (Germany). Inst. fuer Umweltphysik; Neuber, R.; Eisinger, M. [Alfred-Wegener-Institut fuer Polar- und Meeresforschung, Potsdam (Germany)

    2000-04-01

    The Global Ozone Monitoring Experiment (GOME) was launched on 21 April 1995 as one of six scientific instruments on board the second European remote sensing satellite (ERS-2) of the ESA. The investigations presented here aimed at assessing and improving the accuracy of the GOME measurements of sun-standardized and absolute radiation density and the derived data products. For this purpose, the GOME data were compared with measurements pf terrestrial, airborne and satellite-borne systems. For scientific reasons, the measurements will focus on the medium and high latitudes of both hemispheres, although equatorial regions were investigated as well. In the first stage, operational data products of GOME were validated, i.e. radiation measurements (spectra, level1 product) and trace gas column densities (level2 product). [German] Am 21. April 1995 wurde das Global Ozone Monitoring Experiment (GOME) als eines von insgesamt sechs wissenschaftlichen Instrumenten an Bord des zweiten europaeischen Fernerkundungssatelliten (ERS-2) der ESA ins All gebracht. Das Ziel dieses Vorhabens ist es, die Genauigkeit der von GOME durchgefuehrten Messungen von sonnennormierter und absoluter Strahlungsdichte sowie der aus ihnen abgeleiteten Datenprodukte zu bewerten und zu verbessern. Dazu sollten die GOME-Daten mit Messungen von boden-, flugzeug- und satellitengestuetzten Systemen verglichen werden. Aus wissenschaftlichen Gruenden wird der Schwerpunkt auf Messungen bei mittleren und hohen Breitengraden in beiden Hemisphaeren liegen. Jedoch wurden im Laufe des Projektzeitraumes auch Regionen in Aequatornaehe untersucht. Im ersten Schritt sollen operationelle Datenprodukte von GOME validiert werden. Dieses sind Strahlungsmessungen (Spektren, Level1-Produkt) und Spurengas-Saeulendichten (Level2-Produkt). (orig.)

  14. A multi-model analysis of vertical ozone profiles

    Directory of Open Access Journals (Sweden)

    J. E. Jonson

    2010-06-01

    Full Text Available A multi-model study of the long-range transport of ozone and its precursors from major anthropogenic source regions was coordinated by the Task Force on Hemispheric Transport of Air Pollution (TF HTAP under the Convention on Long-range Transboundary Air Pollution (LRTAP. Vertical profiles of ozone at 12-h intervals from 2001 are available from twelve of the models contributing to this study and are compared here with observed profiles from ozonesondes. The contributions from each major source region are analysed for selected sondes, and this analysis is supplemented by retroplume calculations using the FLEXPART Lagrangian particle dispersion model to provide insight into the origin of ozone transport events and the cause of differences between the models and observations.

    In the boundary layer ozone levels are in general strongly affected by regional sources and sinks. With a considerably longer lifetime in the free troposphere, ozone here is to a much larger extent affected by processes on a larger scale such as intercontinental transport and exchange with the stratosphere. Such individual events are difficult to trace over several days or weeks of transport. This may explain why statistical relationships between models and ozonesonde measurements are far less satisfactory than shown in previous studies for surface measurements at all seasons. The lowest bias between model-calculated ozone profiles and the ozonesonde measurements is seen in the winter and autumn months. Following the increase in photochemical activity in the spring and summer months, the spread in model results increases, and the agreement between ozonesonde measurements and the individual models deteriorates further.

    At selected sites calculated contributions to ozone levels in the free troposphere from intercontinental transport are shown. Intercontinental transport is identified based on differences in model calculations with unperturbed emissions and

  15. Unequivocal detection of ozone recovery in the Antarctic Ozone Hole through significant increases in atmospheric layers with minimum ozone

    Science.gov (United States)

    de Laat, Jos; van Weele, Michiel; van der A, Ronald

    2015-04-01

    An important new landmark in present day ozone research is presented through MLS satellite observations of significant ozone increases during the ozone hole season that are attributed unequivocally to declining ozone depleting substances. For many decades the Antarctic ozone hole has been the prime example of both the detrimental effects of human activities on our environment as well as how to construct effective and successful environmental policies. Nowadays atmospheric concentrations of ozone depleting substances are on the decline and first signs of recovery of stratospheric ozone and ozone in the Antarctic ozone hole have been observed. The claimed detection of significant recovery, however, is still subject of debate. In this talk we will discuss first current uncertainties in the assessment of ozone recovery in the Antarctic ozone hole by using multi-variate regression methods, and, secondly present an alternative approach to identify ozone hole recovery unequivocally. Even though multi-variate regression methods help to reduce uncertainties in estimates of ozone recovery, great care has to be taken in their application due to the existence of uncertainties and degrees of freedom in the choice of independent variables. We show that taking all uncertainties into account in the regressions the formal recovery of ozone in the Antarctic ozone hole cannot be established yet, though is likely before the end of the decade (before 2020). Rather than focusing on time and area averages of total ozone columns or ozone profiles, we argue that the time evolution of the probability distribution of vertically resolved ozone in the Antarctic ozone hole contains a better fingerprint for the detection of ozone recovery in the Antarctic ozone hole. The advantages of this method over more tradition methods of trend analyses based on spatio-temporal average ozone are discussed. The 10-year record of MLS satellite measurements of ozone in the Antarctic ozone hole shows a

  16. Budget calculations for ozone and its precursors: Seasonal and episodic features based on model simulations

    NARCIS (Netherlands)

    Memmesheimer, M.; Ebel, A.; Roemer, M.

    1997-01-01

    Results from two air quality models (LOTOS, EURAD) have been used to analyse the contribution of the different terms in the continuity equation to the budget of ozone, NO(x) and PAN. Both models cover large parts of Europe and describe the processes relevant for tropospheric chemistry and dynamics.

  17. Modeling of recovery mechanism of ozone zero phenomenaby adding small amount of nitrogen in atmospheric pressure oxygen dielectric barrier discharges

    Science.gov (United States)

    Akashi, Haruaki; Yoshinaga, Tomokazu

    2013-09-01

    Ozone zero phenomena in an atmospheric pressure oxygen dielectric barrier discharges have been one of the major problems during a long time operation of ozone generators. But it is also known that the adding a small amount of nitrogen makes the recover from the ozone zero phenomena. To make clear the mechanism of recovery, authors have been simulated the discharges with using the results of Ref. 3. As a result, the recovery process can be seen and ozone density increased. It is found that the most important species would be nitrogen atoms. The reaction of nitrogen atoms and oxygen molecules makes oxygen atoms which is main precursor species of ozone. This generation of oxygen atoms is effective to increase ozone. The dependence of oxygen atom density (nO) and nitrogen atom density (nN) ratio was examined in this paper. In the condition of low nN/nO ratio case, generation of nitrogen oxide is low, and the quenching of ozone by the nitrogen oxide would be low. But in the high ratio condition, the quenching of ozone by nitrogen oxide would significant. This work was supported by KAKENHI(23560352).

  18. The effect of ambient ozone and humidity on the performance of nylon and Teflon filters used in ambient air monitoring filter-pack systems

    Science.gov (United States)

    PE Padgett

    2010-01-01

    Nylon and Teflon filter media are frequently used for monitoring ambient air pollutants. These media are subject to many environmental factors that may influence adsorption and retention of particulate and gaseous nitrogenous pollutants. This study evaluated the effects of ozone and humidity on the efficacy of nylon and Teflon filters used in the US dry deposition...

  19. Application of ozone micro-nano-bubbles to groundwater remediation.

    Science.gov (United States)

    Hu, Liming; Xia, Zhiran

    2018-01-15

    Ozone is widely used for water treatment because of its strong oxidation ability. However, the efficiency of ozone in groundwater remediation is limited because of its relatively low solubility and rapid decomposition in the aqueous phase. Methods for increasing the stability of ozone within the subsurface are drawing increasing attention. Micro-nano-bubbles (MNBs), with diameters ranging from tens of nanometres to tens of micrometres, present rapid mass transfer rates, persist for a relatively long time in water, and transport with groundwater flow, which significantly improve gas concentration and provide a continuous gas supply. Therefore, MNBs show a considerable potential for application in groundwater remediation. In this study, the characteristics of ozone MNBs were examined, including their size distribution, bubble quantity, and zeta potential. The mass transfer rate of ozone MNBs was experimentally investigated. Ozone MNBs were then used to treat organics-contaminated water, and they showed remarkable cleanup efficiency. Column tests were also conducted to study the efficiency of ozone MNBs for organics-contaminated groundwater remediation. Based on the laboratory tests, field monitoring was conducted on a trichloroethylene (TCE)-contaminated site. The results showed that ozone MNBs can greatly improve remediation efficiency and represent an innovative technology for in situ remediation of organics-contaminated groundwater. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  20. Mass tracking for chemical analysis: the causes of ozone formation in southern Ontario during BAQS-Met 2007

    Directory of Open Access Journals (Sweden)

    P. A. Makar

    2010-11-01

    Full Text Available A three-level nested regional air pollution model has been used to study the processes leading to high ozone concentrations in the southern Great Lakes region of North America. The highest resolution simulations show that complex interactions between the lake-breeze circulation and the synoptic flow lead to significant enhancements in the photochemical production and transport of ozone at the local scale. Mass tracking of individual model processes show that Lakes Erie and St. Clair frequently act as photochemical ozone production regions, with average mid-day production rates of up to 3 ppbv per hour. Enhanced ozone levels are evident over these two lakes in 23-day-average surface ozone fields. Analysis of other model fields and aircraft measurements suggests that vertical circulation enhances ozone levels at altitudes up to 1500 m over Lake St. Clair, whereas subsidence enhances ozone over Lake Erie in a shallow layer only 250 m deep. Mass tracking of model transport shows that lake-breeze surface convergence zones combined with the synoptic flow can then carry ozone and its precursors hundreds of kilometers from these source areas, in narrow, elongated features. Comparison with surface mesonet ozone observations confirm the presence, magnitude, and timing of these features, which can create local ozone enhancements on the order of 30 ppbv above the regional ozone levels. Sensitivity analyses of model-predicted ozone and HOx concentrations show that most of the region is VOC-limited, and that the secondary oxidation pathways of aromatic hydrocarbons have a key role in setting the region's ozone and HOx levels.

  1. Ozonation for source treatment of pharmaceuticals in hospital wastewater - ozone lifetime and required ozone dose

    DEFF Research Database (Denmark)

    Hansen, Kamilla Marie Speht; Spiliotopoulou, Aikaterini; Chhetri, Ravi Kumar

    2016-01-01

    Ozonation aimed at removing pharmaceuticals was studied in an effluent from an experimental pilot system using staged moving bed biofilm reactor (MBBR) tanks for the optimal biological treatment of wastewater from a medical care unit of Aarhus University Hospital. Dissolved organic carbon (DOC......) and pH in samples varied considerably, and the effect of these two parameters on ozone lifetime and the efficiency of ozone in removing pharmaceuticals were determined. The pH in the effluent varied from 5.0 to 9.0 resulting in approximately a doubling of the required ozone dose at the highest p......H for each pharmaceutical. DOC varied from 6 to 20 mg-DOC/L. The ozone required for removing each pharmaceutical, varied linearly with DOC and thus, ozone doses normalized to DOC (specific ozone dose) agreed between water samples (typically within 15%). At neutral pH the specific ozone dose required...

  2. Exposure-Relevant Ozone Chemistry in Occupied Spaces

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, Beverly Kaye [Univ. of California, Berkeley, CA (United States)

    2009-04-01

    Ozone, an ambient pollutant, is transformed into other airborne pollutants in the indoor environment. In this dissertation, the type and amount of byproducts that result from ozone reactions with common indoor surfaces, surface residues, and vapors were determined, pollutant concentrations were related to occupant exposure, and frameworks were developed to predict byproduct concentrations under various indoor conditions. In Chapter 2, an analysis is presented of secondary organic aerosol formation from the reaction of ozone with gas-phase, terpene-containing consumer products in small chamber experiments under conditions relevant for residential and commercial buildings. The full particle size distribution was continuously monitored, and ultrafine and fine particle concentrations were in the range of 10 to>300 mu g m-3. Particle nucleation and growth dynamics were characterized.Chapter 3 presents an investigation of ozone reactions with aircraft cabin surfaces including carpet, seat fabric, plastics, and laundered and worn clothing fabric. Small chamber experiments were used to determine ozone deposition velocities, ozone reaction probabilities, byproduct emission rates, and byproduct yields for each surface category. The most commonly detected byproducts included C1?C10 saturated aldehydes and skin oil oxidation products. For all materials, emission rates were higher with ozone than without. Experimental results were used to predict byproduct exposure in the cabin and compare to other environments. Byproduct levels are predicted to be similar to ozone levels in the cabin, which have been found to be tens to low hundreds of ppb in the absence of an ozone converter. In Chapter 4, a model is presented that predicts ozone uptake by and byproduct emission from residual chemicals on surfaces. The effects of input parameters (residue surface concentration, ozone concentration, reactivity of the residue and the surface, near-surface airflow conditions, and

  3. Background Ozone in Southern China During 1994-2015: Role of Anthropogenic Emission and Climate Change

    Science.gov (United States)

    Wang, T.; Zhang, L.; Poon, S.

    2016-12-01

    Tropospheric ozone plays important roles in atmospheric chemistry, air quality, and climate. Changes in background ozone concentrations and underlying causes are therefore of great interest to the scientific community and governments. Compared with North America and Europe, long-term measurements of background ozone in China are scarce. This study reports the longest continuous ozone record in southern China measured at a background site (Hok Tsui) in Hong Kong during 1994-2015. The analysis of the 22-year record shows that the surface ozone in the background atmosphere of southern China has been increasing, with an overall Theil-Sen estimated rate of 0.43 ppbv/yr. Compared with our previous results during 1994-2007 (Wang et al., 2009), the average rate of increase has slowed down over during 2008-2015 (0.32 vs. 0.58 ppbv/yr), possibly due to smaller increase or even decrease in ozone precursors emission in mainland China in recent years. The average rates of change show significant seasonal differences with the largest rate occurring in summer (0.32, 0.55, 0.52, and 0.36 ppbv/yr in spring, summer, autumn, and winter, respectively). Monthly mean ozone concentrations at Hok Tsui are compared against an East Asian Monsoon index. It is found that only the summer-time ozone over period 2008-2015 has a strong positive correlation with the index, suggesting that climate might have played an important role in driving the ozone increase observed in summer since 2008. The ozone trend in Hong Kong will be compared to those from other regions in East Asia, and the role of emission changes in Asia will be discussed.

  4. The impact of anthropogenic and biogenic emissions on surface ozone concentrations in Istanbul.

    Science.gov (United States)

    Im, Ulas; Poupkou, Anastasia; Incecik, Selahattin; Markakis, Konstantinos; Kindap, Tayfun; Unal, Alper; Melas, Dimitros; Yenigun, Orhan; Topcu, Sema; Odman, M Talat; Tayanc, Mete; Guler, Meltem

    2011-03-01

    Surface ozone concentrations at Istanbul during a summer episode in June 2008 were simulated using a high resolution and urban scale modeling system coupling MM5 and CMAQ models with a recently developed anthropogenic emission inventory for the region. Two sets of base runs were performed in order to investigate for the first time the impact of biogenic emissions on ozone concentrations in the Greater Istanbul Area (GIA). The first simulation was performed using only the anthropogenic emissions whereas the second simulation was performed using both anthropogenic and biogenic emissions. Biogenic NMVOC emissions were comparable with anthropogenic NMVOC emissions in terms of magnitude. The inclusion of biogenic emissions significantly improved the performance of the model, particularly in reproducing the low night time values as well as the temporal variation of ozone concentrations. Terpene emissions contributed significantly to the destruction of the ozone during nighttime. Biogenic NMVOCs emissions enhanced ozone concentrations in the downwind regions of GIA up to 25ppb. The VOC/NO(x) ratio almost doubled due to the addition of biogenic NMVOCs. Anthropogenic NO(x) and NMVOCs were perturbed by ±30% in another set of simulations to quantify the sensitivity of ozone concentrations to the precursor emissions in the region. The sensitivity runs, as along with the model-calculated ozone-to-reactive nitrogen ratios, pointed NO(x)-sensitive chemistry, particularly in the downwind areas. On the other hand, urban parts of the city responded more to changes in NO(x) due to very high anthropogenic emissions. Copyright © 2010 Elsevier B.V. All rights reserved.

  5. Regional-scale modeling of near-ground ozone in the Central East China, source attributions and an assessment of outflow to East Asia The role of regional-scale transport during MTX2006

    Science.gov (United States)

    Li, J.; Wang, Z.; Akimoto, H.; Yamaji, K.; Takigawa, M.; Pochanart, P.; Liu, Y.; Kanaya, Y.

    2008-07-01

    A 3-D regional chemical transport model, the Nested Air Quality Prediction Model System (NAQPMS), with an on-line tracer tagging module was applied to study the source of the near-ground (pollutants. In particular, the model captured highly polluted and clean cases well. The simulated near-ground ozone over CEC is 60 85 ppbv (parts per billion by volume), higher than those (20 50 ppbv) in Japan and over the North Pacific. The simulated tagged tracer indicates that the regional-scale transport of chemically produced ozone over other areas in CEC contributes to the most fractions (49%) of the near-ground mean ozone at Mt. Tai in June, rather than the in-situ photochemistry (12%). Due to high anthropogenic and biomass burning emissions, the contributions of the ground ozone from the southern part of CEC plays the most important role (32.4 ppbv, 37.9% of total ozone) in the monthly mean ozone concentration at Mt. Tai, which even reached 59 ppbv (62%) on 6 7 June 2006. The monthly mean horizontal distribution of chemically produced ozone from various source regions indicates that the spatial distribution of O3 over CEC is controlled by the photochemical reactions. In addition, the regional-scale transport of pollutants also plays an important role in the spatial and temporal distribution of ozone over CEC. The chemically produced ozone from the southern part of the study region can be transported northeastwardly to the northern rim of CEC. The mean contribution is 5 10 ppbv, and it can reach 25 ppbv during high ozone events. This work also studied the outflow of CEC ozone and its precursors, as well as their influences and contributions to the ozone level over adjacent regions/countries. It shows that the contribution of CEC ozone to mean ozone mixing ratios over Korea Peninsula and Japan is 5 15 ppbv, of which about half was due to the direct transport of ozone from CEC and half was contributed by the ozone produced locally by the transported ozone precursors from CEC.

  6. Effects of anthropogenic emissions on tropospheric ozone and its radiative forcing

    Energy Technology Data Exchange (ETDEWEB)

    Berntsen, T.; Isaksen, I.S.A.; Fuglestvedt, J.S.; Myhre, G.; Larsen, T. Alsvik; Stordal, F.; Freckleton, R.S.; Shine, K.P.

    1997-12-31

    As described in this report, changes in tropospheric ozone since pre-industrial times due to changes in emissions have been calculated by the University of Oslo global three-dimensional photochemical model. The radiative forcing caused by the increase in ozone has been calculated by means of two independent radiative transfer models: the University of Reading model (Reading), and the University of Oslo/Norwegian Institute for Air Research model (OsloRad). Significant increases in upper tropospheric ozone concentrations are found at northern mid-latitudes at about 10 km altitude. In the tropical regions the largest increase is found at about 15 km altitude. The increase is found to be caused mainly by enhanced in situ production due to transport of precursors from the boundary layer, with a smaller contribution from increased transport of ozone produced in the boundary layer. The lifetime of ozone in the troposphere decreased by about 35% as a result of enhanced concentrations of HO{sub 2}. The calculated increase in surface ozone in Europe is in good agreement with observations. The calculations of radiative forcing include the effect of clouds and allow for thermal adjustment in the stratosphere. The global and annual averaged radiative forcing at the tropopause from both models are in the lower part of the Intergovernmental Panel on Climate Change estimated range. The calculated radiative forcing is similar in magnitude to the negative radiative forcing by sulfate aerosols, but displaced southward in source regions at northern mid-latitudes. The increase in tropospheric ozone is calculated to have cooled the lower stratosphere by up to 0.9 K, with possibly half of this cooling occurring in the past 2 to 3 decades. 76 refs., 16 figs., 9 tabs.

  7. Spatio-temporal observations of the tertiary ozone maximum

    Directory of Open Access Journals (Sweden)

    V. F. Sofieva

    2009-07-01

    Full Text Available We present spatio-temporal distributions of the tertiary ozone maximum (TOM, based on GOMOS (Global Ozone Monitoring by Occultation of Stars ozone measurements in 2002–2006. The tertiary ozone maximum is typically observed in the high-latitude winter mesosphere at an altitude of ~72 km. Although the explanation for this phenomenon has been found recently – low concentrations of odd-hydrogen cause the subsequent decrease in odd-oxygen losses – models have had significant deviations from existing observations until recently. Good coverage of polar night regions by GOMOS data has allowed for the first time to obtain spatial and temporal observational distributions of night-time ozone mixing ratio in the mesosphere.

    The distributions obtained from GOMOS data have specific features, which are variable from year to year. In particular, due to a long lifetime of ozone in polar night conditions, the downward transport of polar air by the meridional circulation is clearly observed in the tertiary ozone maximum time series. Although the maximum tertiary ozone mixing ratio is achieved close to the polar night terminator (as predicted by the theory, TOM can be observed also at very high latitudes, not only in the beginning and at the end, but also in the middle of winter. We have compared the observational spatio-temporal distributions of the tertiary ozone maximum with that obtained using WACCM (Whole Atmosphere Community Climate Model and found that the specific features are reproduced satisfactorily by the model.

    Since ozone in the mesosphere is very sensitive to HOx concentrations, energetic particle precipitation can significantly modify the shape of the ozone profiles. In particular, GOMOS observations have shown that the tertiary ozone maximum was temporarily destroyed during the January 2005 and December 2006 solar proton events as a result of the HOx enhancement from the increased ionization.

  8. A preliminary comparison between TOVS and GOME level 2 ozone data

    Science.gov (United States)

    Rathman, William; Monks, Paul S.; Llewellyn-Jones, David; Burrows, John P.

    1997-09-01

    A preliminary comparison between total column ozone concentration values derived from TIROS Operational Vertical Sounder (TOVS) and Global Ozone Monitoring Experiment (GOME) has been carried out. Two comparisons of ozone datasets have been made: a) TOVS ozone analysis maps vs. GOME level 2 data; b) TOVS data located at Northern Hemisphere Ground Ozone Stations (NHGOS) vs. GOME data. Both analyses consistently showed an offset in the value of the total column ozone between the datasets [for analyses a) 35 Dobson Units (DU); and for analyses b) 10 DU], despite a good correlation between the spatial and temporal features of the datasets. A noticeably poor correlation in the latitudinal bands 10°/20° North and 10°/20° South was observed—the reasons for which are discussed. The smallest region which was statistically representative of the ozone value correlation dataset of TOVS data at NHGOS and GOME level-2 data was determined to be a region that was enclosed by effective radius of 0.75 arc-degrees (83.5km).

  9. Ozone fumigation (twice ambient) reduces leaf infestation following natural and artificial inoculation by the endophytic fungus Apiognomonia errabunda of adult European beech trees

    International Nuclear Information System (INIS)

    Olbrich, Maren; Knappe, Claudia; Wenig, Marion; Gerstner, Elke; Haeberle, Karl-Heinz; Kitao, Mitsutoshi; Matyssek, Rainer; Stich, Susanne; Leuchner, Michael; Werner, Herbert; Schlink, Katja; Mueller-Starck, Gerhard; Welzl, Gerhard; Scherb, Hagen; Ernst, Dieter; Heller, Werner; Bahnweg, Guenther

    2010-01-01

    In 2006, a controlled infection study was performed in the 'Kranzberger Forst' to address the following questions: (1) Will massive artificial inoculation with Apiognomonia errabunda override the previously observed inhibitory effect of chronic ozone? (2) Can biochemical or molecular markers be detected to account for the action of ozone? To this end six adult beech trees were chosen, three ozone fumigated (2x ozone) and three control trees (ambient = 1x ozone). Spore-sprayed branches of sun and shade crown positions of each of the trees, and uninoculated control branches, were enclosed in 100-L plastic bags for one night to facilitate infection initiation. Samples were taken within a five-week period after inoculation. A. errabunda infestation levels quantified by real-time PCR increased in leaves that were not fumigated with additional ozone. Cell wall components and ACC (ethylene precursor 1-amino cyclopropane-1-carboxylic acid) increased upon ozone fumigation and may in part lead to the repression of fungal infection. - Chronic sublethal ozone exposure reduces both natural and artificial infestation of beech leaves by the endophytic fungus Apiognomonia errabunda.

  10. Ozone fumigation (twice ambient) reduces leaf infestation following natural and artificial inoculation by the endophytic fungus Apiognomonia errabunda of adult European beech trees

    Energy Technology Data Exchange (ETDEWEB)

    Olbrich, Maren; Knappe, Claudia; Wenig, Marion; Gerstner, Elke [Institute of Biochemical Plant Pathology, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, 85764 Neuherberg (Germany); Haeberle, Karl-Heinz; Kitao, Mitsutoshi; Matyssek, Rainer [Forest Botany, Technische Universitaet Muenchen, Am Hochanger 13, 85354 Freising (Germany); Stich, Susanne [Institute of Biochemical Plant Pathology, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, 85764 Neuherberg (Germany); Leuchner, Michael; Werner, Herbert [Bioclimatology, Technische Universitaet Muenchen, Am Hochanger 13, 85354 Freising (Germany); Schlink, Katja; Mueller-Starck, Gerhard [Section of Forest Genetics, Technische Universitaet Muenchen, Am Hochanger 13, 85354 Freising (Germany); Welzl, Gerhard [Institute of Developmental Genetics, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, 85764 Neuherberg (Germany); Scherb, Hagen [Institute of Biomathematics and Biometry, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, 85764 Neuherberg (Germany); Ernst, Dieter; Heller, Werner [Institute of Biochemical Plant Pathology, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, 85764 Neuherberg (Germany); Bahnweg, Guenther, E-mail: bahnweg@helmholtz-muenchen.d [Institute of Biochemical Plant Pathology, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, 85764 Neuherberg (Germany)

    2010-04-15

    In 2006, a controlled infection study was performed in the 'Kranzberger Forst' to address the following questions: (1) Will massive artificial inoculation with Apiognomonia errabunda override the previously observed inhibitory effect of chronic ozone? (2) Can biochemical or molecular markers be detected to account for the action of ozone? To this end six adult beech trees were chosen, three ozone fumigated (2x ozone) and three control trees (ambient = 1x ozone). Spore-sprayed branches of sun and shade crown positions of each of the trees, and uninoculated control branches, were enclosed in 100-L plastic bags for one night to facilitate infection initiation. Samples were taken within a five-week period after inoculation. A. errabunda infestation levels quantified by real-time PCR increased in leaves that were not fumigated with additional ozone. Cell wall components and ACC (ethylene precursor 1-amino cyclopropane-1-carboxylic acid) increased upon ozone fumigation and may in part lead to the repression of fungal infection. - Chronic sublethal ozone exposure reduces both natural and artificial infestation of beech leaves by the endophytic fungus Apiognomonia errabunda.

  11. Tropospheric Ozone Assessment Report: Present-day distribution and trends of tropospheric ozone relevant to climate and global atmospheric chemistry model evaluation

    Directory of Open Access Journals (Sweden)

    A. Gaudel

    2018-05-01

    Full Text Available 'The Tropospheric Ozone Assessment Report' (TOAR is an activity of the International Global Atmospheric Chemistry Project. This paper is a component of the report, focusing on the present-day distribution and trends of tropospheric ozone relevant to climate and global atmospheric chemistry model evaluation. Utilizing the TOAR surface ozone database, several figures present the global distribution and trends of daytime average ozone at 2702 non-urban monitoring sites, highlighting the regions and seasons of the world with the greatest ozone levels. Similarly, ozonesonde and commercial aircraft observations reveal ozone’s distribution throughout the depth of the free troposphere. Long-term surface observations are limited in their global spatial coverage, but data from remote locations indicate that ozone in the 21st century is greater than during the 1970s and 1980s. While some remote sites and many sites in the heavily polluted regions of East Asia show ozone increases since 2000, many others show decreases and there is no clear global pattern for surface ozone changes since 2000. Two new satellite products provide detailed views of ozone in the lower troposphere across East Asia and Europe, revealing the full spatial extent of the spring and summer ozone enhancements across eastern China that cannot be assessed from limited surface observations. Sufficient data are now available (ozonesondes, satellite, aircraft across the tropics from South America eastwards to the western Pacific Ocean, to indicate a likely tropospheric column ozone increase since the 1990s. The 2014–2016 mean tropospheric ozone burden (TOB between 60°N–60°S from five satellite products is 300 Tg ± 4%. While this agreement is excellent, the products differ in their quantification of TOB trends and further work is required to reconcile the differences. Satellites can now estimate ozone’s global long-wave radiative effect, but evaluation is difficult due to limited

  12. Global economic effects of changes in crops, pasture, and forests due to changing climate, carbon dioxide, and ozone

    International Nuclear Information System (INIS)

    Reilly, J.; Paltsev, S.; Felzer, B.; Wang, X.; Kicklighter, D.; Melillo, J.; Prinn, R.; Sarofim, M.; Sokolov, A.; Wang, C.

    2007-01-01

    Multiple environmental changes will have consequences for global vegetation. To the extent that crop yields and pasture and forest productivity are affected, there can be important economic consequences. We examine the combined effects of changes in climate, increases in carbon dioxide (CO 2 ), and changes in tropospheric ozone on crop, pasture, and forest lands and the consequences for the global and regional economies. We examine scenarios where there is limited or little effort to control these substances, and policy scenarios that limit emissions of CO 2 and ozone precursors. We find the effects of climate and CO 2 to be generally positive, and the effects of ozone to be very detrimental. Unless ozone is strongly controlled, damage could offset CO 2 and climate benefits. We find that resource allocation among sectors in the economy, and trade among countries, can strongly affect the estimate of economic effect in a country

  13. Tropospheric Ozone and Photochemical Smog

    Science.gov (United States)

    Sillman, S.

    2003-12-01

    global background ozone can make the effects of local pollution events everywhere more acute, and can also cause ecological damage in remote locations that are otherwise unaffected by urban pollution. Ozone at the global scale is also related to greenhouse warming.This chapter provides an overview of photochemical smog at the urban and regional scale, focused primarily on ozone and including a summary of information about particulates. It includes the following topics: dynamics and extent of pollution events; health and ecological impacts; relation between ozone and precursor emissions, including hydrocarbons and nitrogen oxides (NOx); sources, composition, and fundamental properties of particulates; chemistry of ozone and related species; methods of interpretation based on ambient measurements; and the connection between air pollution events and the chemistry of the global troposphere. Because there are many similarities between the photochemistry of ozone during pollution events and the chemistry of the troposphere in general, this chapter will include some information about global tropospheric chemistry and the links between urban-scale and global-scale events. Additional treatment of the global troposphere is found in Volume 4 of this work. The chemistry of ozone formation discussed here is also related to topics discussed in greater detail elsewhere in this volume (see Chapters 9.10 and 9.12) and in Volume 4.

  14. A New ENSO Index Derived from Satellite Measurements of Column Ozone

    Science.gov (United States)

    Ziemke, J. R.; Chandra, S.; Oman, L. D.; Bhartia, P. K.

    2010-01-01

    Column Ozone measured in tropical latitudes from Nimbus 7 total ozone mapping spectrometer (TOMS), Earth Probe TOMS, solar backscatter ultraviolet (SBUV), and Aura ozone monitoring instrument (OMI) are used to derive an El Nino-Southern Oscillation (ENSO) index. This index, which covers a time period from 1979 to the present, is defined as the Ozone ENSO Index (OEI) and is the first developed from atmospheric trace gas measurements. The OEI is constructed by first averaging monthly mean column ozone over two broad regions in the western and eastern Pacific and then taking their difference. This differencing yields a self-calibrating ENSO index which is independent of individual instrument calibration offsets and drifts in measurements over the long record. The combined Aura OMI and MLS ozone data confirm that zonal variability in total column ozone in the tropics caused by ENSO events lies almost entirely in the troposphere. As a result, the OEI can be derived directly from total column ozone instead of tropospheric column ozone. For clear-sky ozone measurements a +1K change in Nino 3.4 index corresponds to +2.9 Dobson Unit (DU) change in the OEI, while a +1 hPa change in SOI coincides with a -1.7DU change in the OEI. For ozone measurements under all cloud conditions these numbers are +2.4DU and -1.4 DU, respectively. As an ENSO index based upon ozone, it is potentially useful in evaluating climate models predicting long term changes in ozone and other trace gases.

  15. Validation of Copernicus Height-resolved Ozone data Products from Sentinel-5P TROPOMI using global sonde and lidar networks (CHEOPS-5P)

    Science.gov (United States)

    Keppens, Arno; Lambert, Jean-Christopher; Hubert, Daan; Verhoelst, Tijl; Granville, José; Ancellet, Gérard; Balis, Dimitris; Delcloo, Andy; Duflot, Valentin; Godin-Beekmann, Sophie; Koukouli, Marilisa; Leblanc, Thierry; Stavrakou, Trissevgeni; Steinbrecht, Wolfgang; Stübi, Réné; Thompson, Anne

    2017-04-01

    Monitoring of and research on air quality, stratospheric ozone and climate change require global and long-term observation of the vertical distribution of atmospheric ozone, at ever-improving resolution and accuracy. Global tropospheric and stratospheric ozone profile measurement capabilities from space have therefore improved substantially over the last decades. Being a part of the space segment of the Copernicus Atmosphere and Climate Services that is currently under implementation, the upcoming Sentinel-5 Precursor (S5P) mission with its imaging spectrometer TROPOMI (Tropospheric Monitoring Instrument) is dedicated to the measurement of nadir atmospheric radiance and solar irradiance in the UV-VIS-NIR-SWIR spectral range. Ozone profile and tropospheric ozone column data will be retrieved from these measurements by use of several complementary retrieval methods. The geophysical validation of the enhanced height-resolved ozone data products, as well as support to the continuous evolution of the associated retrieval algorithms, is a key objective of the CHEOPS-5P project, a contributor to the ESA-led S5P Validation Team (S5PVT). This work describes the principles and implementation of the CHEOPS-5P quality assessment (QA) and validation system. The QA/validation methodology relies on the analysis of S5P retrieval diagnostics and on comparisons of S5P data with reference ozone profile measurements. The latter are collected from ozonesonde, stratospheric lidar and tropospheric lidar stations performing network operation in the context of WMO's Global Atmosphere Watch, including the NDACC global and SHADOZ tropical networks. After adaptation of the Multi-TASTE versatile satellite validation environment currently operational in the context of ESA's CCI, EUMETSAT O3M-SAF, and CEOS and SPARC initiatives, a list of S5P data Quality Indicators (QI) will be derived from complementary investigations: (1) data content and information content studies of the S5P data retrievals

  16. Ozone Layer Protection

    Science.gov (United States)

    ... and Research Centers Contact Us Share Ozone Layer Protection The stratospheric ozone layer is Earth’s “sunscreen” – protecting ... GreenChill Partnership Responsible Appliance Disposal (RAD) Program Ozone Protection vs. Ozone Pollution This website addresses stratospheric ozone ...

  17. Southern Hemisphere Additional Ozonesondes (SHADOZ) Ozone Climatology (2005-2009): Tropospheric and Tropical Tropopause Layer (TTL) Profiles with Comparisons to Omi-based Ozone Products

    Science.gov (United States)

    Thompson, Anne M.; Miller, Sonya K.; Tilmes, Simone; Kollonige, Debra W.; Witte, Jacquelyn C.; Oltmans, Samuel J.; Johnson, Brian J.; Fujiwara, Masatomo; Schmidlin, F. J.; Coetzee, G. J. R.; hide

    2012-01-01

    We present a regional and seasonal climatology of SHADOZ ozone profiles in the troposphere and tropical tropopause layer (TTL) based on measurements taken during the first five years of Aura, 2005-2009, when new stations joined the network at Hanoi, Vietnam; Hilo, Hawaii; Alajuela Heredia, Costa Rica; Cotonou, Benin. In all, 15 stations operated during that period. A west-to-east progression of decreasing convective influence and increasing pollution leads to distinct tropospheric ozone profiles in three regions: (1) western Pacific eastern Indian Ocean; (2) equatorial Americas (San Cristobal, Alajuela, Paramaribo); (3) Atlantic and Africa. Comparisons in total ozone column from soundings, the Ozone Monitoring Instrument (OMI, on Aura, 2004-) satellite and ground-based instrumentation are presented. Most stations show better agreement with OMI than they did for EPTOMS comparisons (1998-2004; Earth-ProbeTotal Ozone Mapping Spectrometer), partly due to a revised above-burst ozone climatology. Possible station biases in the stratospheric segment of the ozone measurement noted in the first 7 years of SHADOZ ozone profiles are re-examined. High stratospheric bias observed during the TOMS period appears to persist at one station. Comparisons of SHADOZ tropospheric ozone and the daily Trajectory-enhanced Tropospheric Ozone Residual (TTOR) product (based on OMIMLS) show that the satellite-derived column amount averages 25 low. Correlations between TTOR and the SHADOZ sondes are quite good (typical r2 0.5-0.8), however, which may account for why some published residual-based OMI products capture tropospheric interannual variability fairly realistically. On the other hand, no clear explanations emerge for why TTOR-sonde discrepancies vary over a wide range at most SHADOZ sites.

  18. Productions of Volatile Organic Compounds (VOCs) in Surface Waters from Reactions with Atmospheric Ozone

    Science.gov (United States)

    Hopkins, Frances; Bell, Thomas; Yang, Mingxi

    2017-04-01

    Ozone (O3) is a key atmospheric oxidant, greenhouse gas and air pollutant. In marine environments, some atmospheric ozone is lost by reactions with aqueous compounds (e.g. dissolved organic material, DOM, dimethyl sulfide, DMS, and iodide) near the sea surface. These reactions also lead to formations of volatile organic compounds (VOCs). Removal of O3 by the ocean remains a large uncertainty in global and regional chemical transport models, hampering coastal air quality forecasts. To better understand the role of the ocean in controlling O3 concentrations in the coastal marine atmosphere, we designed and implemented a series of laboratory experiments whereby ambient surface seawater was bubbled with O3-enriched, VOC-free air in a custom-made glass bubble equilibration system. Gas phase concentrations of a range of VOCs were monitored continuously over the mass range m/z 33 - 137 at the outflow of the bubble equilibrator by a proton transfer reaction - mass spectrometer (PTR-MS). Gas phase O3 was also measured at the input and output of the equilibrator to monitor the uptake due to reactions with dissolved compounds in seawater. We observed consistent productions of a variety of VOCs upon reaction with O3, notably isoprene, aldehydes, and ketones. Aqueous DMS is rapidly removed from the reactions with O3. To test the importance of dissolved organic matter precursors, we added increasing (milliliter) volumes of Emiliania huxleyi culture to the equilibrator filled with aged seawater, and observed significant linear increases in gas phase concentrations of a number of VOCs. Reactions between DOM and O3 at the sea-air interface represent a potentially significant source of VOCs in marine air and a sink of atmospheric O3.

  19. Combined UV treatment and ozonation for the removal of by-product precursors in swimming pool water

    DEFF Research Database (Denmark)

    Cheema, Waqas Akram; Kaarsholm, Kamilla Marie Speht; Andersen, Henrik Rasmus

    2017-01-01

    Both UV treatment and ozonation are used to reduce different types of disinfection by-products (DBPs) in swimming pools. UV treatment is the most common approach, as it is particularly efficient at removing combined chlorine. However, the UV treatment of pool water increases chlorine reactivity...

  20. ISOTOPIC (14C) AND CHEMICAL COMPOSITION OF ATMOSPHERIC VOLATILE ORGANIC COMPOUND FRACTIONS - PRECURSORS TO OZONE FORMATION

    Science.gov (United States)

    Atmospheric volatile organic compounds (VOCs) are an important factor in the production of ozone near ground level [3]. Many hydrocarbons originate from auto exhaust. However, a number of VOCs, e.g., isoprene, are known to be natural in origin. To develop reliable models for un...

  1. Extreme value analysis for evaluating ozone control strategies.

    Science.gov (United States)

    Reich, Brian; Cooley, Daniel; Foley, Kristen; Napelenok, Sergey; Shaby, Benjamin

    2013-06-01

    Tropospheric ozone is one of six criteria pollutants regulated by the US EPA, and has been linked to respiratory and cardiovascular endpoints and adverse effects on vegetation and ecosystems. Regional photochemical models have been developed to study the impacts of emission reductions on ozone levels. The standard approach is to run the deterministic model under new emission levels and attribute the change in ozone concentration to the emission control strategy. However, running the deterministic model requires substantial computing time, and this approach does not provide a measure of uncertainty for the change in ozone levels. Recently, a reduced form model (RFM) has been proposed to approximate the complex model as a simple function of a few relevant inputs. In this paper, we develop a new statistical approach to make full use of the RFM to study the effects of various control strategies on the probability and magnitude of extreme ozone events. We fuse the model output with monitoring data to calibrate the RFM by modeling the conditional distribution of monitoring data given the RFM using a combination of flexible semiparametric quantile regression for the center of the distribution where data are abundant and a parametric extreme value distribution for the tail where data are sparse. Selected parameters in the conditional distribution are allowed to vary by the RFM value and the spatial location. Also, due to the simplicity of the RFM, we are able to embed the RFM in our Bayesian hierarchical framework to obtain a full posterior for the model input parameters, and propagate this uncertainty to the estimation of the effects of the control strategies. We use the new framework to evaluate three potential control strategies, and find that reducing mobile-source emissions has a larger impact than reducing point-source emissions or a combination of several emission sources.

  2. Evaluation of passive methods for measuring ozone in the European Alps

    Energy Technology Data Exchange (ETDEWEB)

    Hangartner, M. [Inst. of Applied Ergonomics and Hygiene, Zurich (Switzerland); Kirchner, M. [GSF Research Centre for Environment and Human Health, Neuherberg (Germany); Werner, H. [Munich Univ. (Germany). Inst. for Bioclimatology and Environmental Research

    1995-12-31

    Under the leadership of the GSF research centre, various research groups were invited to make their ozone and nitrogen oxide collection systems available for comparative testing. It was considered valuable to include not only well developed systems but also methods still under development. For the main comparative test 11 working groups with differing methods took part. Essentially the goal was to evaluate of the integrating ozone measuring methods as compared to continual ozone monitoring methods under field conditions. For this the various collection systems at 6 alpine continual measuring stations in Italy and Bavaria characterising different location types, were compared over 22 weeks

  3. Biocidal action of ozone-treated polystyrene surfaces on vegetative and sporulated bacteria

    International Nuclear Information System (INIS)

    Mahfoudh, Ahlem; Barbeau, Jean; Moisan, Michel; Leduc, Annie; Seguin, Jacynthe

    2010-01-01

    Surfaces of materials can be modified to ensure specific interaction features with microorganisms. The current work discloses biocidal properties of polystyrene (PS) Petri-dish surfaces that have been exposed to a dry gaseous-ozone flow. Such treated PS surfaces are able to inactivate various species of vegetative and sporulated bacteria on a relatively short contact time. Denaturation of proteins seems likely based on a significant loss of enzymatic activity of the lysozyme protein. Characterization of these surfaces by atomic-force microscopy (AFM), Fourier-transform infra-red (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) reveals specific structural and chemical modifications as compared to untreated PS. Persistence of the biocidal properties of these treated surfaces is observed. This ozone-induced process is technically simple to achieve and does not require active precursors as in grafting.

  4. Two Years of Ozone Vertical Profiles Collected from Aircraft over California and the Pacific Ocean

    Science.gov (United States)

    Austerberry, D.; Yates, E. L.; Roby, M.; Chatfield, R. B.; Iraci, L. T.; Pierce, B.; Fairlie, T. D.; Johnson, B. J.; Ives, M.

    2012-12-01

    Tropospheric ozone transported across the Pacific Ocean has been strongly suggested to contribute substantially to surface ozone levels at several sites within Northern California's Sacramento Valley. Because this contribution can affect a city's ability to meet regulatory ozone limits, the influence of Pacific ozone transport has implications for air quality control strategies in the San Joaquin Valley (SJV). The Alpha Jet Atmospheric Experiment is designed to collect a multi-year data set of tropospheric ozone vertical profiles. Forty-four flights with ozone profiles were conducted between February 2nd, 2011 and August 9th, 2012, and approximately ten more flights are expected in the remainder of 2012. Twenty marine air profiles have been collected at sites including Trinidad Head and two locations tens of kilometers offshore at 37° N latitude. Good agreement is seen with ozonesondes launched from Trinidad Head. Additional profiles over Merced, California were obtained on many of these flight days. These in-situ measurements were conducted during spiral descents of H211's Alpha Jet at mid-day local times using a 2B Technologies Dual Beam Ozone Monitor. Hourly surface ambient ozone data were obtained from the California Air Resources Board's SJV monitoring sites. For each site, the Pearson linear correlation coefficient was calculated between ozone in a 300m vertical layer of an offshore profile and the surface site at varying time offsets from the time of the profile. Each site's local and regional ozone production component was estimated and removed. The resulting correlations suggest instances of Pacific ozone transport following some of the offshore observations. Real-Time Air Quality Modeling System (RAQMS) products constrained by assimilated satellite data model the transport of ozone enhancements and guide flight planning. RAQMS hindcasts also suggest that ozone transport to the surface of the SJV basin occurred following some of these offshore profiles

  5. Comparative study of ozonized olive oil and ozonized sunflower oil

    Directory of Open Access Journals (Sweden)

    Díaz Maritza F.

    2006-01-01

    Full Text Available In this study the ozonized olive and sunflower oils are chemical and microbiologically compared. These oils were introduced into a reactor with bubbling ozone gas in a water bath at room temperature until they were solidified. The peroxide, acidity and iodine values along with antimicrobial activity were determined. Ozonization effects on the fatty acid composition of these oils were analyzed using Gas-Liquid Chromatographic Technique. An increase in peroxidation and acidity values was observed in both oils but they were higher in ozonized sunflower oil. Iodine value was zero in ozonized olive oil whereas in ozonized sunflower was 8.8 g Iodine per 100 g. The antimicrobial activity was similar for both ozonized oils except for Minimum Bactericidal Concentrations of Pseudomona aeruginosa. Composition of fatty acids in both ozonized oils showed gradual decrease in unsaturated fatty acids (C18:1, C18:2 with gradual increase in ozone doses.

  6. Evaluation of the Ozone Fields in NASA's MERRA-2 Reanalysis

    Science.gov (United States)

    Wargan, Krzysztof; Labow, Gordon; Frith, Stacey; Pawson, Steven; Livesey, Nathaniel; Partyka, Gary

    2017-01-01

    We describe and assess the quality of the assimilated ozone product from the Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA-2) produced at NASAs Global Modeling and Assimilation Office (GMAO) spanning the time period from 1980 to present. MERRA-2 assimilates partial column ozone retrievals from a series of Solar Backscatter Ultraviolet (SBUV) radiometers on NASA and NOAA spacecraft between January 1980 and September 2004; starting in October 2004 retrieved ozone profiles from the Microwave Limb Sounder (MLS) and total column ozone from the Ozone Monitoring Instrument on NASAs EOS Aura satellite are assimilated. We compare the MERRA-2 ozone with independent satellite and ozonesonde data focusing on the representation of the spatial and temporal variability of stratospheric and upper tropospheric ozone and on implications of the change in the observing system from SBUV to EOS Aura. The comparisons show agreement within 10 (standard deviation of the difference) between MERRA-2 profiles and independent satellite data in most of the stratosphere. The agreement improves after 2004 when EOS Aura data are assimilated. The standard deviation of the differences between the lower stratospheric and upper tropospheric MERRA-2 ozone and ozonesondes is 11.2 and 24.5, respectively, with correlations of 0.8 and above, indicative of a realistic representation of the near-tropopause ozone variability in MERRA-2. The agreement improves significantly in the EOS Aura period, however MERRA-2 is biased low in the upper troposphere with respect to the ozonesondes. Caution is recommended when using MERRA-2 ozone for decadal changes and trend studies.

  7. A direct sensitivity approach to predict hourly ozone resulting from compliance with the National Ambient Air Quality Standard.

    Science.gov (United States)

    Simon, Heather; Baker, Kirk R; Akhtar, Farhan; Napelenok, Sergey L; Possiel, Norm; Wells, Benjamin; Timin, Brian

    2013-03-05

    In setting primary ambient air quality standards, the EPA's responsibility under the law is to establish standards that protect public health. As part of the current review of the ozone National Ambient Air Quality Standard (NAAQS), the US EPA evaluated the health exposure and risks associated with ambient ozone pollution using a statistical approach to adjust recent air quality to simulate just meeting the current standard level, without specifying emission control strategies. One drawback of this purely statistical concentration rollback approach is that it does not take into account spatial and temporal heterogeneity of ozone response to emissions changes. The application of the higher-order decoupled direct method (HDDM) in the community multiscale air quality (CMAQ) model is discussed here to provide an example of a methodology that could incorporate this variability into the risk assessment analyses. Because this approach includes a full representation of the chemical production and physical transport of ozone in the atmosphere, it does not require assumed background concentrations, which have been applied to constrain estimates from past statistical techniques. The CMAQ-HDDM adjustment approach is extended to measured ozone concentrations by determining typical sensitivities at each monitor location and hour of the day based on a linear relationship between first-order sensitivities and hourly ozone values. This approach is demonstrated by modeling ozone responses for monitor locations in Detroit and Charlotte to domain-wide reductions in anthropogenic NOx and VOCs emissions. As seen in previous studies, ozone response calculated using HDDM compared well to brute-force emissions changes up to approximately a 50% reduction in emissions. A new stepwise approach is developed here to apply this method to emissions reductions beyond 50% allowing for the simulation of more stringent reductions in ozone concentrations. Compared to previous rollback methods, this

  8. Tropospheric Ozone Assessment Report: Present-day ozone distribution and trends relevant to human health

    Directory of Open Access Journals (Sweden)

    Zoë L. Fleming

    2018-02-01

    Full Text Available This study quantifies the present-day global and regional distributions (2010–2014 and trends (2000–2014 for five ozone metrics relevant for short-term and long-term human exposure. These metrics, calculated by the Tropospheric Ozone Assessment Report, are: 4th highest daily maximum 8-hour ozone (4MDA8; number of days with MDA8 > 70 ppb (NDGT70, SOMO35 (annual Sum of Ozone Means Over 35 ppb and two seasonally averaged metrics (3MMDA1; AVGMDA8. These metrics were explored at ozone monitoring sites worldwide, which were classified as urban or non-urban based on population and nighttime lights data. Present-day distributions of 4MDA8 and NDGT70, determined predominantly by peak values, are similar with highest levels in western North America, southern Europe and East Asia. For the other three metrics, distributions are similar with North–South gradients more prominent across Europe and Japan. Between 2000 and 2014, significant negative trends in 4MDA8 and NDGT70 occur at most US and some European sites. In contrast, significant positive trends are found at many sites in South Korea and Hong Kong, with mixed trends across Japan. The other three metrics have similar, negative trends for many non-urban North American and some European and Japanese sites, and positive trends across much of East Asia. Globally, metrics at many sites exhibit non-significant trends. At 59% of all sites there is a common direction and significance in the trend across all five metrics, whilst 4MDA8 and NDGT70 have a common trend at ~80% of all sites. Sensitivity analysis shows AVGMDA8 trends differ with averaging period (warm season or annual. Trends are unchanged at many sites when a 1995–2014 period is used; although fewer sites exhibit non-significant trends. Over the longer period 1970–2014, most Japanese sites exhibit positive 4MDA8/SOMO35 trends. Insufficient data exist to characterize ozone trends for the rest of Asia and other world regions.

  9. Development of pollution reduction strategies for Mexico City: Estimating cost and ozone reduction effectiveness

    International Nuclear Information System (INIS)

    Thayer, G.R.; Hardie, R.W.; Barrera-Roldan, A.

    1993-01-01

    This reports on the collection and preparation of data (costs and air quality improvement) for the strategic evaluation portion of the Mexico City Air Quality Research Initiative (MARI). Reports written for the Mexico City government by various international organizations were used to identify proposed options along with estimates of cost and emission reductions. Information from appropriate options identified by SCAQMD for Southem California were also used in the analysis. A linear optimization method was used to select a group of options or a strategy to be evaluated by decision analysis. However, the reduction of ozone levels is not a linear function of the reduction of hydrocarbon and NO x emissions. Therefore, a more detailed analysis was required for ozone. An equation for a plane on an isopleth calculated with a trajectory model was obtained using two endpoints that bracket the expected total ozone precursor reductions plus the starting concentrations for hydrocarbons and NO x . The relationship between ozone levels and the hydrocarbon and NO x concentrations was assumed to lie on this plane. This relationship was used in the linear optimization program to select the options comprising a strategy

  10. Ozone in the atmosphere. Basic principles, natural and human impacts

    Energy Technology Data Exchange (ETDEWEB)

    Fabian, Peter [Technical Univ. Munich (Germany). Immission Research; Dameris, Martin [German Aerospace Center (DLR), Oberpfaffenhofen-Wessling (Germany). Inst. of Atmospheric Physics

    2014-09-01

    climate changes. For many years he has been an active contributor to the WMO scientific ozone depletion assessments, which have been used to monitor the depletion and recovery of the ozone layer in accordance with the Montreal Protocol.

  11. Ozone in the atmosphere. Basic principles, natural and human impacts

    International Nuclear Information System (INIS)

    Fabian, Peter; Dameris, Martin

    2014-01-01

    climate changes. For many years he has been an active contributor to the WMO scientific ozone depletion assessments, which have been used to monitor the depletion and recovery of the ozone layer in accordance with the Montreal Protocol.

  12. Detection of Changes in Ground-Level Ozone Concentrations via Entropy

    Directory of Open Access Journals (Sweden)

    Yuehua Wu

    2015-04-01

    Full Text Available Ground-level ozone concentration is a key indicator of air quality. Theremay exist sudden changes in ozone concentration data over a long time horizon, which may be caused by the implementation of government regulations and policies, such as establishing exhaust emission limits for on-road vehicles. To monitor and assess the efficacy of these policies, we propose a methodology for detecting changes in ground-level ozone concentrations, which consists of three major steps: data transformation, simultaneous autoregressive modelling and change-point detection on the estimated entropy. To show the effectiveness of the proposed methodology, the methodology is applied to detect changes in ground-level ozone concentration data collected in the Toronto region of Canada between June and September for the years from 1988 to 2009. The proposed methodology is also applicable to other climate data.

  13. Efficiency of ozone production by pulsed positive corona discharge in synthetic air

    Energy Technology Data Exchange (ETDEWEB)

    Simek, Milan [Institute of Plasma Physics, Department of Pulsed Plasma Systems, Academy of Sciences of the Czech Republic, Prague (Czech Republic)]. E-mail: simek@ipp.cas.cz; Clupek, Martin [Institute of Plasma Physics, Department of Pulsed Plasma Systems, Academy of Sciences of the Czech Republic, Prague (Czech Republic)

    2002-06-07

    We have studied the efficiency of ozone production by pulsed positive corona discharge in coaxial wire-cylinder geometry at atmospheric pressure. A corona discharge was generated by short ({approx}150 ns) high voltage pulses applied between a silver coated copper wire anode and stainless steel cylinder cathode in synthetic air. A pyrex probe and Teflon tube was used for collecting discharge products and an ozone concentration was monitored outside of the discharge chamber by a non-dispersive UV absorption technique. The production of ozone was investigated as a function of energy density (10{sup -4}-3x10{sup -1} Wh l{sup -1}) delivered to the discharge volume by combining the discharge frequency (0.1-10 Hz) and airflow rate (1-32 l min{sup -1}). From ozone concentration measurements we have evaluated the ozone production, yield and production energy cost. The ozone production yield and cost vary in the range of 15-55 g kWh{sup -1} and 35-110 eV/molecule. (author)

  14. Spatial distribution of ozone over Indonesia (Study case: Forest fire event 2015)

    Science.gov (United States)

    Muslimah, Sri; Buce Saleh, Muhamad; Hidayat, Rahmat

    2018-05-01

    Tropospheric ozone is known as surface ozone and caused several health impact. The objective of this study was to analysis spatial distribution of tropospheric ozone over Indonesia case study forest fire event in 2015. Monthly observation measured by Ozone Monitoring Instrument (OMI) have been analysed from January – December 2015 to study spatial distribution of tropospheric ozone related to forest fire event 2015. The study discovered high level of tropospheric column ozone (TCO) from October to November 2015. The result shows increasing average of TCO from September to October almost 6 DU. Meanwhile, monthly number of hotspot is higher in September 2015 with total number 257 hotspot which is acquired by Moderate Resolution Imaging Spectrometer (MODIS) Terra version 6.1 with confidence level same or more than 90%. The hotspot distribution compared with spatial TCO distribution and shows interesting time lag with respect to hotspot distribution, one month. Further study for daily comparison of TCO and forest fire event needed. This result suggested that the tropospheric ozone over the Indonesian region increases in 2015 were remarkable and corresponded to forest fire event.

  15. Ozone's impact on public health: Contributions from indoor exposures to ozone and products of ozone-initiated chemistry

    DEFF Research Database (Denmark)

    Weschler, Charles J.

    2006-01-01

    OBJECTIVES: The associations between ozone concentrations measured outdoors and both morbidity and mortality may be partially due to indoor exposures to ozone and ozone-initiated oxidation products. In this article I examine the contributions of such indoor exposures to overall ozone-related heal...

  16. Trends in air concentration and deposition at background monitoring sites in Sweden - major inorganic compounds, heavy metals and ozone

    Energy Technology Data Exchange (ETDEWEB)

    Kindbom, K.; Svensson, Annika; Sjoeberg, K.; Pihl Karlsson, G.

    2001-09-01

    This report describes concentrations in air of sulphur compounds, soot, nitrogen compounds and ozone in Sweden between 1985-1998. Time trends of concentration in precipitation and deposition of sulphate, nitrate, ammonium, acidity, base cations and chloride in six different regions covering Sweden are evaluated during the period 1983-1998. Trends of heavy metals in precipitation have been analysed for the period 1983-1998 and the change in heavy metal concentration, 1975-1995, in mosses is described. Data used in the trend analyses originates from measurements performed at six Swedish EMEP stations and from approximately 25 stations within the national Precipitation Chemistry Network. Two different statistical methods, linear regression and the non-parametric Mann Kendall test, have been used to evaluate changes in annual mean values. Time trends of concentration of sulphur dioxide, particulate sulphate, soot, nitrogen dioxide, total nitrate and total ammonium in air show highly significant decreasing trends, except for soot at one station in northern Sweden. Concentrations of ozone have a strong seasonal variation with a peak occurring in spring every year. However, annual ozone concentrations show no obvious trends in spite of decreasing emissions of the precursors NOx and VOC. A slight indication of a decreasing trend in the number of ozone episodes might be seen from 1990 to 1998. Sulphate concentrations in precipitation and deposition show strongly significant decreasing trends in the whole country. Concentrations and deposition of nitrate and ammonium have been decreasing in all areas except for nitrate at stations in south-west and north-west Sweden and ammonium in south-west Sweden. Acidity has decreased in all areas since 1989, resulting in increasing pH values in Sweden. The interannual variations of concentration and deposition of base cations and chloride are large and few general trends can be seen during 1983-1997. Time trends of four heavy metals in

  17. Ozone modeling within plasmas for ozone sensor applications

    OpenAIRE

    Arshak, Khalil; Forde, Edward; Guiney, Ivor

    2007-01-01

    peer-reviewed Ozone (03) is potentially hazardous to human health and accurate prediction and measurement of this gas is essential in addressing its associated health risks. This paper presents theory to predict the levels of ozone concentration emittedfrom a dielectric barrier discharge (DBD) plasma for ozone sensing applications. This is done by postulating the kinetic model for ozone generation, with a DBD plasma at atmospheric pressure in air, in the form of a set of rate equations....

  18. Ozonation of acid yellow 17 dye in a semi-batch bubble column

    International Nuclear Information System (INIS)

    Lackey, Laura W.; Mines, Richard O.; McCreanor, Philip T.

    2006-01-01

    A semi-batch bubble column was used to evaluate the effect of ozonation on the removal of acid yellow 17 dye from water. Results indicate that ozonation is very effective at removing acid yellow 17 dye from synthetic textile wastewater. The ozone consumed to apparent dye removal ratio ranged from 2 to 15,000 mg ozone per mg of dye decolorized and was dependent on both ozonation time and apparent dye concentration. The biodegradability of the dye wastewater was evaluated by monitoring changes in 5-day biochemical oxygen demand (BOD 5 ) with respect to chemical oxygen demand (COD). Results indicate that the wastewater biodegradability increased with an increase in ozonation time. Film theory was used to kinetically model the gas-liquid reactions occurring in the reactor. Modeling results indicated that during the first 10-15 min of ozonation, the system could be characterized by a fast, pseudo-first-order regime. With continued ozonation, system kinetics transitioned through a moderate then to a slow regime. Successful modeling of this period required use of a kinetic equation corresponding to a more inclusive condition. Model results are presented

  19. Nitrogen oxides transport from La Cygne Station, KS: A study for assessing its influence on urban ozone. Final report

    International Nuclear Information System (INIS)

    Blumenthal, D.L.

    1998-02-01

    As a result of the new ozone and PM 2.5 national ambient air quality standards, it appears that the Kansas City metropolitan area will be classified as nonattainment with respect to ozone. The Kansas Department of Health and Environment (KDHE) is planning to develop a new Kansas State Implementation Plan (SIP) to address this issue between 1997 and 2000 with implementation scheduled for 2004. Some Ozone Transport Assessment Group (OTAG) related air quality analyses have indicated that the Kansas City area is subject to surface and aloft windfields that could carry ozone or ozone precursors into Kansas City from outside the region, including from other parts of the state of Kansas. But questions have arisen whether or not local emission reductions would be more effective in achieving ozone standards. To better understand the causes of high ozone in the region and, specifically, to understand the role of emissions from certain power generating stations, the NO x Steering Committee was formed. The Committee includes representatives of the Kansas Department of Health and Environment and two local utility companies (Kansas City Power and Light (KCPL) and Western Resources). Input was also solicited from the US Environmental Protection Agency (EPA). This report presents the results of a scoping study commissioned by the Committee

  20. Numerical simulation for regional ozone concentrations: A case study by weather research and forecasting/chemistry (WRF/Chem) model

    Energy Technology Data Exchange (ETDEWEB)

    Habib Al Razi, Khandakar Md; Hiroshi, Moritomi [Environmental and Renewable Energy System, Graduate School of Engineering, Gifu University, 1-1 Yanagido, Gifu City, 501-1193 (Japan)

    2013-07-01

    The objective of this research is to better understand and predict the atmospheric concentration distribution of ozone and its precursor (in particular, within the Planetary Boundary Layer (Within 110 km to 12 km) over Kasaki City and the Greater Tokyo Area using fully coupled online WRF/Chem (Weather Research and Forecasting/Chemistry) model. In this research, a serious and continuous high ozone episode in the Greater Tokyo Area (GTA) during the summer of 14–18 August 2010 was investigated using the observation data. We analyzed the ozone and other trace gas concentrations, as well as the corresponding weather conditions in this high ozone episode by WRF/Chem model. The simulation results revealed that the analyzed episode was mainly caused by the impact of accumulation of pollution rich in ozone over the Greater Tokyo Area. WRF/Chem has shown relatively good performance in modeling of this continuous high ozone episode, the simulated and the observed concentrations of ozone, NOx and NO2 are basically in agreement at Kawasaki City, with best correlation coefficients of 0.87, 0.70 and 0.72 respectively. Moreover, the simulations of WRF/Chem with WRF preprocessing software (WPS) show a better agreement with meteorological observations such as surface winds and temperature profiles in the ground level of this area. As a result the surface ozone simulation performances have been enhanced in terms of the peak ozone and spatial patterns, whereas WRF/Chem has been succeeded to generate meteorological fields as well as ozone, NOx, NO2 and NO.

  1. A Fast and Sensitive New Satellite SO2 Retrieval Algorithm based on Principal Component Analysis: Application to the Ozone Monitoring Instrument

    Science.gov (United States)

    Li, Can; Joiner, Joanna; Krotkov, A.; Bhartia, Pawan K.

    2013-01-01

    We describe a new algorithm to retrieve SO2 from satellite-measured hyperspectral radiances. We employ the principal component analysis technique in regions with no significant SO2 to capture radiance variability caused by both physical processes (e.g., Rayleigh and Raman scattering and ozone absorption) and measurement artifacts. We use the resulting principal components and SO2 Jacobians calculated with a radiative transfer model to directly estimate SO2 vertical column density in one step. Application to the Ozone Monitoring Instrument (OMI) radiance spectra in 310.5-340 nm demonstrates that this approach can greatly reduce biases in the operational OMI product and decrease the noise by a factor of 2, providing greater sensitivity to anthropogenic emissions. The new algorithm is fast, eliminates the need for instrument-specific radiance correction schemes, and can be easily adapted to other sensors. These attributes make it a promising technique for producing longterm, consistent SO2 records for air quality and climate research.

  2. Ozonation kinetics of winery wastewater in a pilot-scale bubble column reactor.

    Science.gov (United States)

    Lucas, Marco S; Peres, José A; Lan, Bing Yan; Li Puma, Gianluca

    2009-04-01

    The degradation of organic substances present in winery wastewater was studied in a pilot-scale, bubble column ozonation reactor. A steady reduction of chemical oxygen demand (COD) was observed under the action of ozone at the natural pH of the wastewater (pH 4). At alkaline and neutral pH the degradation rate was accelerated by the formation of radical species from the decomposition of ozone. Furthermore, the reaction of hydrogen peroxide (formed from natural organic matter in the wastewater) and ozone enhances the oxidation capacity of the ozonation process. The monitoring of pH, redox potential (ORP), UV absorbance (254 nm), polyphenol content and ozone consumption was correlated with the oxidation of the organic species in the water. The ozonation of winery wastewater in the bubble column was analysed in terms of a mole balance coupled with ozonation kinetics modeled by the two-film theory of mass transfer and chemical reaction. It was determined that the ozonation reaction can develop both in and across different kinetic regimes: fast, moderate and slow, depending on the experimental conditions. The dynamic change of the rate coefficient estimated by the model was correlated with changes in the water composition and oxidant species.

  3. Meteorological and chemical impacts on ozone formation: A case study in Hangzhou, China

    Science.gov (United States)

    Li, Kangwei; Chen, Linghong; Ying, Fang; White, Stephen J.; Jang, Carey; Wu, Xuecheng; Gao, Xiang; Hong, Shengmao; Shen, Jiandong; Azzi, Merched; Cen, Kefa

    2017-11-01

    Regional ozone pollution has become one of the most challenging problems in China, especially in the more economically developed and densely populated regions like Hangzhou. In this study, measurements of O3, CO, NOx and non-methane hydrocarbons (NMHCs), together with meteorological data, were obtained for the period July 1, 2013-August 15, 2013 at three sites in Hangzhou. These sites included an urban site (Zhaohui ;ZH;), a suburban site (Xiasha ;XS;) and a rural site (Qiandaohu ;QDH;). During the observation period, both ZH and XS had a higher ozone level than QDH, with exceeding rates of 41.3% and 47.8%, respectively. Elevated O3 levels in QDH were found at night, which could be explained by less prominent NO titration effect in rural area. Detailed statistical analysis of meteorological and chemical impacts on ozone formation was carried out for ZH, and higher ozone concentration was observed when the wind direction was from the east. This is possibly due to emissions of VOCs from XS, a typical chemical industrial park located in 30 km upwind area of ZH. A comprehensive comparison between three ozone episode periods and one non-episode period were made in ZH. It was concluded that elevated concentrations of precursors and temperatures, low relative humidity and wind speed and easterly-dominated wind direction contribute to urban ozone episodes in Hangzhou. VOCs reactivity analysis indicated that reactive alkenes like isoprene and isobutene contributed most to ozone formation. Three methods were applied to evaluate O3-VOCs-NOx sensitivity in ZH: VOCs/NOx ratio method, Smog Production Model (SPM) and Relative Incremental Reactivity (RIR). The results show that summer ozone in urban Hangzhou mostly presents VOCs-limited and transition region alternately. Our study implies that the increasing automobiles and VOCs emissions from upwind area could result in ozone pollution in urban Hangzhou, and synergistic reduction of VOCs and NOx will be more effective.

  4. Ozone decomposition

    Directory of Open Access Journals (Sweden)

    Batakliev Todor

    2014-06-01

    Full Text Available Catalytic ozone decomposition is of great significance because ozone is a toxic substance commonly found or generated in human environments (aircraft cabins, offices with photocopiers, laser printers, sterilizers. Considerable work has been done on ozone decomposition reported in the literature. This review provides a comprehensive summary of the literature, concentrating on analysis of the physico-chemical properties, synthesis and catalytic decomposition of ozone. This is supplemented by a review on kinetics and catalyst characterization which ties together the previously reported results. Noble metals and oxides of transition metals have been found to be the most active substances for ozone decomposition. The high price of precious metals stimulated the use of metal oxide catalysts and particularly the catalysts based on manganese oxide. It has been determined that the kinetics of ozone decomposition is of first order importance. A mechanism of the reaction of catalytic ozone decomposition is discussed, based on detailed spectroscopic investigations of the catalytic surface, showing the existence of peroxide and superoxide surface intermediates

  5. Adsorption of N-nitrosodimethylamine precursors by powdered and granular activated carbon.

    Science.gov (United States)

    Hanigan, David; Zhang, Jinwei; Herckes, Pierre; Krasner, Stuart W; Chen, Chao; Westerhoff, Paul

    2012-11-20

    Activated carbon (AC) has been shown to remove precursors of halogenated disinfection byproducts. Granular and powdered activated carbon (GAC, PAC) were investigated for their potential to adsorb N-nitrosodimethylamine (NDMA) precursors from blends of river water and effluent from a wastewater treatment plant (WWTP). At bench scale, waters were exposed to lignite or bituminous AC, either as PAC in bottle point experiments or as GAC in rapid small-scale column tests (RSSCTs). NDMA formation potential (FP) was used as a surrogate for precursor removal. NDMA FP was reduced by 37, 59, and 91% with 3, 8, and 75 mg/L of one PAC, respectively, with a 4-h contact time. In RSSCTs and in full-scale GAC contactors, NDMA FP removal always exceeded that of the bulk dissolved organic carbon (DOC) and UV absorbance at 254 nm. For example, whereas DOC breakthrough exceeded 90% of its influent concentration after 10,000 bed volumes of operation in an RSSCT, NDMA FP was less than 40% of influent concentration after the same bed life of the GAC. At full or pilot scale, high NDMA FP reduction ranging from >60 to >90% was achieved across GAC contactors, dependent upon the GAC bed life and/or use of a preoxidant (chlorine or ozone). In all experiments, NDMA formation was not reduced to zero, which suggests that although some precursors are strongly sorbed, others are not. This is among the first studies to show that AC is capable of adsorbing NDMA precursors, but further research is needed to better understand NDMA precursor chemical properties (e.g., hydrophobicity, molecular size) and evaluate how best to incorporate this finding into full-scale designs and practice.

  6. High Precision, Absolute Total Column Ozone Measurements from the Pandora Spectrometer System: Comparisons with Data from a Brewer Double Monochromator and Aura OMI

    Science.gov (United States)

    Tzortziou, Maria A.; Herman, Jay R.; Cede, Alexander; Abuhassan, Nader

    2012-01-01

    We present new, high precision, high temporal resolution measurements of total column ozone (TCO) amounts derived from ground-based direct-sun irradiance measurements using our recently deployed Pandora single-grating spectrometers. Pandora's small size and portability allow deployment at multiple sites within an urban air-shed and development of a ground-based monitoring network for studying small-scale atmospheric dynamics, spatial heterogeneities in trace gas distribution, local pollution conditions, photochemical processes and interdependencies of ozone and its major precursors. Results are shown for four mid- to high-latitude sites where different Pandora instruments were used. Comparisons with a well calibrated double-grating Brewer spectrometer over a period of more than a year in Greenbelt MD showed excellent agreement and a small bias of approximately 2 DU (or, 0.6%). This was constant with slant column ozone amount over the full range of observed solar zenith angles (15-80), indicating adequate Pandora stray light correction. A small (1-2%) seasonal difference was found, consistent with sensitivity studies showing that the Pandora spectral fitting TCO retrieval has a temperature dependence of 1% per 3K, with an underestimation in temperature (e.g., during summer) resulting in an underestimation of TCO. Pandora agreed well with Aura-OMI (Ozone Measuring Instrument) satellite data, with average residuals of <1% at the different sites when the OMI view was within 50 km from the Pandora location and OMI-measured cloud fraction was <0.2. The frequent and continuous measurements by Pandora revealed significant short-term (hourly) temporal changes in TCO, not possible to capture by sun-synchronous satellites, such as OMI, alone.

  7. Ozone and ozone injury on plants in and around Beijing, China

    International Nuclear Information System (INIS)

    Wan, Wuxing; Manning, W.J.; Wang, Xiaoke; Zhang, Hongxing; Sun, Xu; Zhang, Qianqian

    2014-01-01

    Ozone (O 3 ) levels were assessed for the first time with passive samplers at 10 sites in and around Beijing in summer 2012. Average O 3 concentrations were higher at locations around Beijing than in the city center. Levels varied with site locations and ranged from 22.5 to 48.1 ppb and were highest at three locations. Hourly O 3 concentrations exceeded 40 ppb for 128 h and 80 ppb for 17 h from 2 to 9 in August at one site, where it had a real-time O 3 analyzer. Extensive foliar O 3 injury was found on 19 species of native and cultivated trees, shrubs, and herbs at 6 of the 10 study sites and the other 2 sites without passive sampler. This is the first report of O 3 foliar injury in and around Beijing. Our results warrant an extensive program of O 3 monitoring and foliar O 3 injury assessment in and around Beijing. - Highlights: • Plants have been threatened by high O 3 concentration in and around Beijing, China. • 19 plant species are reported as obvious ambient O 3 injury symptoms in Beijing. • The O 3 injury symptoms occur more often where ambient O 3 concentration is higher. • The results warrant more extensive and long-term study of ambient O 3 in China. - First report of ozone incidence and ozone injury on plants in and around Beijing, China

  8. Ozone and ultraviolet radiation. Observations and research in the Netherlands and Belgium

    International Nuclear Information System (INIS)

    1997-01-01

    An overview of recent scientific research in Belgium and the Netherlands on the title subject is given. After an overall introduction on ozone and ultraviolet radiation in chapter 1 attention is paid to observations and monitoring of ozone and UV-radiation in chapter 2 and recent research projects in the Netherlands and Belgium with respect to those quantities in chapter 3. In chapter 4 the biological effects of UV-radiation are described, while in chapter 5 the international policy to protect the ozone layer is discussed as well as the effects of such policy on the UV burden and public health. 10 refs

  9. Photochemical model evaluation of the ground-level ozone impacts on ambient air quality and vegetation health in the Alberta oil sands region: Using present and future emission scenarios

    Science.gov (United States)

    Vijayaraghavan, Krish; Cho, Sunny; Morris, Ralph; Spink, David; Jung, Jaegun; Pauls, Ron; Duffett, Katherine

    2016-09-01

    One of the potential environmental issues associated with oil sands development is increased ozone formation resulting from NOX and volatile organic compound emissions from bitumen extraction, processing and upgrading. To manage this issue in the Athabasca Oil Sands Region (AOSR) in northeast Alberta, a regional multi-stakeholder group, the Cumulative Environmental Management Association (CEMA), developed an Ozone Management Framework that includes a modelling based assessment component. In this paper, we describe how the Community Multi-scale Air Quality (CMAQ) model was applied to assess potential ground-level ozone formation and impacts on ambient air quality and vegetation health for three different ozone precursor cases in the AOSR. Statistical analysis methods were applied, and the CMAQ performance results met the U.S. EPA model performance goal at all sites. The modelled 4th highest daily maximum 8-h average ozone concentrations in the base and two future year scenarios did not exceed the Canada-wide standard of 65 ppb or the newer Canadian Ambient Air Quality Standards of 63 ppb in 2015 and 62 ppb in 2020. Modelled maximum 1-h ozone concentrations in the study were well below the Alberta Ambient Air Quality Objective of 82 ppb in all three cases. Several ozone vegetation exposure metrics were also evaluated to investigate the potential impact of ground-level ozone on vegetation. The chronic 3-months SUM60 exposure metric is within the CEMA baseline range (0-2000 ppb-hr) everywhere in the AOSR. The AOT40 ozone exposure metric predicted by CMAQ did not exceed the United Nations Economic Commission for Europe (UN/ECE) threshold of concern of 3000 ppb-hr in any of the cases but is just below the threshold in high-end future emissions scenario. In all three emission scenarios, the CMAQ predicted W126 ozone exposure metric is within the CEMA baseline threshold of 4000 ppb-hr. This study outlines the use of photochemical modelling of the impact of an industry (oil

  10. On the Role of Convection and Turbulence for Tropospheric Ozone and its Precursors

    International Nuclear Information System (INIS)

    Olivie, D.J.L.

    2005-01-01

    The aim of the work in this thesis is to investigate the convective and diffusive transport in the TM chemistry transport model, and to investigate some aspects of the consequences for NOx. The large inaccuracy and uncertainty in the description of processes like convection and turbulent diffusion, the strong dependence of the radiative forcing of ozone on its vertical distribution, and the strong dependence of the ozone production on the distribution of NOx, are the main motivation. The availability of the ERA-40 data, where convective data and vertical diffusion coefficients are archived, allows a study of the effect of different convective mass flux sets, and different vertical diffusion coefficients on the model-simulated distribution of tracers. In this thesis the following questions are addressed : (1) How large is the sensitivity of the (model simulated) distribution of ozone and nitrogen oxides on (the) convection (parameterisation)?; (2) What requirements should be fulfilled by diffusive transport parameterisations in order to simulate the diurnal cycle in trace gas concentrations?; (3) How large are the differences in concentrations between simulations with archived and off-line diagnosed physical parameterisations?; (4) How do the results of different parameterisations of nitrogen oxide production by lightning compare?; (5) What is the effect of an explicit description of the effect of convective redistribution on the vertical distribution of lightning produced NOx? In Chapter 2, the first question and part of the third question are addressed. Because convection can bring reactive trace gases to the upper troposphere where they can live longer, and possibly are transported to remote regions, it is important to well describe the convective transport. The archival of convective mass fluxes in the ERA-40 data set allows us to drive the convective transport in the TM model. We compare these archived fluxes with the standard off-line diagnosed fluxes used in

  11. Ozone concentrations at a selected high-elevation forest site downwind Mexico City

    Science.gov (United States)

    Torres-JArdon, R.

    2013-05-01

    Torres-Jardón, R.*, Rosas-Pérez, I., Granada-Macías, L. M., Ruiz-Suárez, L. G. Centro de Ciencias de la Atmósfera, UNAM, México D. F. México * rtorres@unam.mx For many years, the vegetation of forest species such as Abies religiosa in natural parks located in the southwest mountains of Mexico City has attracted much attention since these parks have been experiencing a severe decline of unclear etiology. The high ozone levels in the area and the observed naked eye macroscopic, histological and cytological injuries on these species, strongly suggest an important contribution of tropospheric ozone to this deterioration process. Apart of historical short monitoring campaigns for measuring ozone levels in these mountains, it is known just a little is known about the present exposure levels at which the local vegetation is exposed. A continuous ozone analyzer has been in operation since 2011 at a high-elevation forest site (Parque Nacional Miguel Hidalgo, PNMH; 3110 m above mean sea level) located downwind of Mexico City Metropolitan Area (MCMA), in order to characterize the local ozone diel amplitude and its seasonal trend, as well as the influence of MCMA on the local O3 concentrations. Hourly average ozone data in PNMH shows that in general, the diel of ozone concentrations in the forest site has a statistical significant correlation with the pattern of ozone levels observed in several monitoring sites (smog receptor sites) within the MCMA, although the high elevation O3 levels are relatively lower than those in the urban area (around 2200 m above mean sea level). It is possible that a part of the oxidants in the air masses are removed by sink deposition processes during the air mass transport across the hills. The diel amplitude of ozone concentrations is small in the cold season, increasing as the seasons advance to June. As in the city, the highest ozone concentrations occur in April or May and the lowest levels during the rainy season, which extends from

  12. Ozone decay in chemical reactor for ozone-dynamical disintegration of used tyres

    International Nuclear Information System (INIS)

    Golota, V.I.; Manuilenko, O.V.; Taran, G.V.; Dotsenko, Yu.V.; Pismenetskii, A.S.; Zamuriev, A.A.; Benitskaja, V.A.

    2011-01-01

    The ozone decay kinetics in the chemical reactor intended for used tyres disintegration is investigated experimentally and theoretically. Ozone was synthesized in barrierless ozonizers based on the streamer discharge. The chemical reactor for tyres disintegration in the ozone-air environment represents the cylindrical chamber, which feeds from the ozonizer by ozone-air mixture with the specified rate of volume flow, and with known ozone concentration. The output of the used mixture, which rate of volume flow is also known, is carried out through the ozone destructor. As a result of ozone decay in the volume and on the reactor walls, and output of the used mixture from the reactor, the ozone concentration in the reactor depends from time. In the paper, the analytical expression for dependence of ozone concentration in the reactor from time and from the parameters of a problem such as the volumetric feed rate, ozone concentration on the input in the reactor, volume flow rate of the used mixture, the volume of the reactor and the area of its internal surface is obtained. It is shown that experimental results coincide with good accuracy with analytical ones.

  13. Ozone distribution in remote ecologically vulnerable terrain of the southern Sierra Nevada, CA

    International Nuclear Information System (INIS)

    Panek, Jeanne; Saah, David; Esperanza, Annie; Bytnerowicz, Andrzej; Fraczek, Witold; Cisneros, Ricardo

    2013-01-01

    Ozone concentration spatial patterns remain largely uncharacterized across the extensive wilderness areas of the Sierra Nevada, CA, despite being downwind of major pollution sources. These natural areas, including four national parks and four national forests, contain forest species that are susceptible to ozone injury. Forests stressed by ozone are also more vulnerable to other agents of mortality, including insects, pathogens, climate change, and ultimately fire. Here we analyze three years of passive ozone monitor data from the southern Sierra Nevada and interpolate landscape-scale spatial and temporal patterns during the summer-through-fall high ozone concentration period. Segmentation analysis revealed three types of ozone exposure sub-regions: high, low, and variable. Consistently high ozone exposure regions are expected to be most vulnerable to forest mortality. One high exposure sub-region has been documented elsewhere as being further vulnerable to increased drought and fire potential. Identifying such hot-spots of forest vulnerability has utility for prioritizing management. -- Highlights: •Three years of passive ozone sampler data over 49,000 km 2 were analyzed spatially. •Spatial and temporal ozone patterns were mapped across the Sierra Nevada, CA. •Sub-regions of consistently high, low and variable ozone exposure were identified. •The 1700–2400 m elevation band delineated a distinct break in ozone concentration. •This approach has utility for prioritizing management across vulnerable landscapes. -- A passive ozone sampler network in combination with spatial analysis techniques was used to characterize landscape-scale ozone patterns and dynamics, identifying regions of consistently high and low ozone exposure for forest management prioritization

  14. How to most effectively expand the global surface ozone observing network

    Directory of Open Access Journals (Sweden)

    E. D. Sofen

    2016-02-01

    Full Text Available Surface ozone observations with modern instrumentation have been made around the world for more than 40 years. Some of these observations have been made as one-off activities with short-term, specific science objectives and some have been made as part of wider networks which have provided a foundational infrastructure of data collection, calibration, quality control, and dissemination. These observations provide a fundamental underpinning to our understanding of tropospheric chemistry, air quality policy, atmosphere–biosphere interactions, etc. brought together eight of these networks to provide a single data set of surface ozone observations. We investigate how representative this combined data set is of global surface ozone using the output from a global atmospheric chemistry model. We estimate that on an area basis, 25 % of the globe is observed (34 % land, 21 % ocean. Whereas Europe and North America have almost complete coverage, other continents, Africa, South America, Australia, and Asia (12–17 % show significant gaps. Antarctica is surprisingly well observed (78 %. Little monitoring occurs over the oceans, with the tropical and southern oceans particularly poorly represented. The surface ozone over key biomes such as tropical forests and savanna is almost completely unmonitored. A chemical cluster analysis suggests that a significant number of observations are made of polluted air masses, but cleaner air masses whether over the land or ocean (especially again in the tropics are significantly under-observed. The current network is unlikely to see the impact of the El Niño–Southern Oscillation (ENSO but may be capable of detecting other planetary-scale signals. Model assessment and validation activities are hampered by a lack of observations in regions where the models differ substantially, as is the ability to monitor likely changes in surface ozone over the next century. Using our methodology we are able to suggest new

  15. How to most effectively expand the global surface ozone observing network

    Science.gov (United States)

    Sofen, E. D.; Bowdalo, D.; Evans, M. J.

    2016-02-01

    Surface ozone observations with modern instrumentation have been made around the world for more than 40 years. Some of these observations have been made as one-off activities with short-term, specific science objectives and some have been made as part of wider networks which have provided a foundational infrastructure of data collection, calibration, quality control, and dissemination. These observations provide a fundamental underpinning to our understanding of tropospheric chemistry, air quality policy, atmosphere-biosphere interactions, etc. brought together eight of these networks to provide a single data set of surface ozone observations. We investigate how representative this combined data set is of global surface ozone using the output from a global atmospheric chemistry model. We estimate that on an area basis, 25 % of the globe is observed (34 % land, 21 % ocean). Whereas Europe and North America have almost complete coverage, other continents, Africa, South America, Australia, and Asia (12-17 %) show significant gaps. Antarctica is surprisingly well observed (78 %). Little monitoring occurs over the oceans, with the tropical and southern oceans particularly poorly represented. The surface ozone over key biomes such as tropical forests and savanna is almost completely unmonitored. A chemical cluster analysis suggests that a significant number of observations are made of polluted air masses, but cleaner air masses whether over the land or ocean (especially again in the tropics) are significantly under-observed. The current network is unlikely to see the impact of the El Niño-Southern Oscillation (ENSO) but may be capable of detecting other planetary-scale signals. Model assessment and validation activities are hampered by a lack of observations in regions where the models differ substantially, as is the ability to monitor likely changes in surface ozone over the next century. Using our methodology we are able to suggest new sites which would help to close

  16. Vertical and Horizontal Measurements of Ambient Ozone over a Gas and Oil Production Area using a UAV Platform

    Science.gov (United States)

    Jensen, A.; Gowing, I.; Martin, R. S.

    2013-12-01

    During the 2013 wintertime Uintah Basin Ozone Study (UBOS13), an autonomous unmanned aerial vehicle (UAV) platform, coupled with an on-board UV ozone monitor, flew several spatial profiles near the location (Horse Pool) of other concentrated measurements by other co-investigators. The airframe, part of the Utah Water Research Laboratory's (UWRL) AggieAir UAV program, consisted of a custom-built, battery-operated plane with and 2.4 m (8 ft) wing span and a 12.7 cm x 12.7 cm x 30.5 cm payload bay with a carrying capacity of approximately 2.0 kg. With the current power system, the fully-loaded AggieAir UAV can fly for approximately 45 minutes at a nominal airspeed of 13.4 m/s (30 mph). The system can be operated either in manual control or be flown autonomously following preprogrammed waypoints via a built in GPS system. The AggieAir UAV systems were primarily designed for photographic and telemetry tracking projects. For the UBOS13 flights, a 2B Technologies Model 205 Ozone (O3) monitor was modified for minimal weight optimization, wrapped with lightweight insulation and secured into the UAV payload bay. Additionally, HOBO Model H08-001-02 shielded temperature/datalogger was secured to the exterior of the UAV from parallel thermal profile determination. During the study period, three demonstration flight profiles were obtained on February 17 and 18, 2013: two vertical 'curtain' profiles and a pair of 'stacked' horizontal profiles. As recorded by numerous ground-based monitoring sites, the ozone during the UAV test periods was characterized by initial trends of daytime O3 maximums over 130 ppb, followed by a meteorological front partially ventilating the Basin on the evening of Feb. 17th leading to decreased O3 minimums around 40 ppb. However, the ground level O3 rebuilt quickly to ground level maximums approaching 100 ppb. The vertical 'curtain' flown on the evening of Feb. 17th only reached a maximum elevation of about 2160 m ASL (600 m AGL) due to encountering

  17. Artificially ionized region as a source of ozone in the stratosphere

    International Nuclear Information System (INIS)

    Gurevich, Aleksandr V; Litvak, Aleksandr G; Vikharev, A L; Ivanov, O A; Borisov, Nikolai D; Sergeichev, Konstantin F

    2000-01-01

    A set of physical and chemical processes occurring in a microwave stratospheric discharge of nanosecond duration is discussed in connection with the effect they may have locally on the ozone layer in the artificially ionized region (AIR) in the stratosphere. The AIR, to be created at altitudes of 18 - 20 km by the microwave breakdown of air with ground-produced powerful electromagnetic wave beams, is planned for use in the natural physical experiment aimed at active monitoring of the ozone layer (its internal state and a set of plasma-chemical and photochemical processes) by controllably generating a considerable amount of ozone in the stratosphere. Results of relevant theoretical studies are presented, as are those of a large series of laboratory experiments performed under conditions similar to those prevailing in the stratosphere. Discharge regimes securing the efficient growth of ozone concentration are identified and studied in detail. It is demonstrated that such a stratospheric ozonizer is about as efficient as the best ground-based ozonizers used at present. For typical stratospheric conditions (low pressures and temperatures T ∼ 200 - 220 K), it is shown that the intense generation of ozone in a microwave breakdown effected by groups of short nanosecond pulses does not virtually increase the density of nitrogen oxides - gases that play a vital role in catalytic ozone-decomposing reactions. The possibility of effectively producing ozone in prebreakdown electric fields is established experimentally. It is demonstrated that due to its long lifetime, ozone produced locally at altitudes of 18 - 20 km may spread widely under the action of winds and turbulent diffusion, thus leading to an additional - artificial - ozonization of the stratosphere. (reviews of topical problems)

  18. Global impact of road traffic on atmospheric chemical composition and on ozone climate forcing

    Science.gov (United States)

    Niemeier, Ulrike; Granier, Claire; Kornblueh, Luis; Walters, Stacy; Brasseur, Guy P.

    2006-05-01

    Automobile emissions are known to contribute to local air pollution and to photochemical smog in urban areas. The impact of road traffic on the chemical composition of the troposphere at the global scale and on climate forcing is less well quantified. Calculations performed with the chemical transport MOZART-2 model show that the concentrations of ozone and its precursors (NOx, CO, and hydrocarbons) are considerably enhanced in most regions of the Northern Hemisphere in response to current surface traffic. During summertime in the Northern Hemisphere, road traffic has increased the zonally averaged ozone concentration by more than 10% in the boundary layer and in the extratropics by approximately 6% at 500 hPa and 2.5% at 300 hPa. The summertime surface ozone concentrations have increased by typically 1-5 ppbv in the remote regions and by 5-20 ppbv in industrialized regions of the Northern Hemisphere. The corresponding ozone-related radiative forcing is 0.05 Wm-2. In order to assess the sensitivity of potential changes in road traffic intensity, two additional model cases were considered, in which traffic-related emissions in all regions of the world were assumed to be on a per capita basis the same as in Europe and in the United States, respectively. In the second and most dramatic case, the surface ozone concentration increases by 30-50 ppbv (50-100%) in south Asia as compared to the present situation. Under this assumption, the global radiative forcing due to traffic-generated ozone reaches 0.27 Wm-2.

  19. Exploring the roles of temperature and NOx on ozone production in the Sacramento urban plume

    Science.gov (United States)

    Lafranchi, B. W.; Cohen, R. C.

    2009-12-01

    We investigate the role of temperature and NOx (NOx = NO+NO2) on ozone (O3) production in the Sacramento urban plume over a stretch of seven years (2001-2007) using data collected at UC Blodgett Forest Research Station (a forested site in the Sierra Nevadas about 80 km downwind of Sacramento, CA) and at a series of California Air Resources Board (CARB) sites along the Sacramento-Blodgett transect. The consistent daytime wind patterns between the Central Valley of California and the foothills of the Sierra Nevada mountains permits the assumption of plume transport from downtown Sacramento, over the CARB monitoring sites in the eastern suburbs, and past the Blodgett Forest research site. While NOx emissions are limited primarily to the urban and suburban regions of the transect, biogenic volatile organic compound (VOC) emissions are significant throughout the transect, thus there is a fast transition from VOC-limited to NOx-limited as the plume travels away from the urban center, and we have the opportunity to analyze the differences in ozone production across these two chemical regimes. For this analysis, the Sacramento-Blodgett transect is separated into three segments: urban, suburban, and rural, defined by the locations of selected monitoring sites. Ozone concentrations across each segment are controlled by chemical production (Pchem) and loss (Lchem), deposition to surfaces (Ldep), and mixing with background air (Lmix). At an assumed deposition rate, mixing rate, and background O3 concentration, the net chemical flux of ozone (Pchem - Lchem) can be inferred from differences in ozone concentrations between adjacent monitoring sites. We show that ozone production rates, in general, increase with temperature. We also show that decreases in NOx emissions over the period from 2001-2007 have been effective at reducing ozone production at all points along the transect, but only on days where temperatures are highest. At low temperatures, this decrease is less apparent

  20. Effects of conventional ozonation and electro-peroxone pretreatment of surface water on disinfection by-product formation during subsequent chlorination.

    Science.gov (United States)

    Mao, Yuqin; Guo, Di; Yao, Weikun; Wang, Xiaomao; Yang, Hongwei; Xie, Yuefeng F; Komarneni, Sridhar; Yu, Gang; Wang, Yujue

    2018-03-01

    The electro-peroxone (E-peroxone) process is an emerging ozone-based electrochemical advanced oxidation process that combines conventional ozonation with in-situ cathodic hydrogen peroxide (H 2 O 2 ) production for oxidative water treatment. In this study, the effects of the E-peroxone pretreatment on disinfection by-product (DBP) formation from chlorination of a synthetic surface water were investigated and compared to conventional ozonation. Results show that due to the enhanced transformation of ozone (O 3 ) to hydroxyl radicals (OH) by electro-generated H 2 O 2 , the E-peroxone process considerably enhanced dissolved organic carbon (DOC) abatement and significantly reduced bromate (BrO 3 - ) formation compared to conventional ozonation. However, natural organic matter (NOM) with high UV 254 absorbance, which is the major precursors of chlorination DBPs, was less efficiently abated during the E-peroxone process than conventional ozonation. Consequently, while both conventional ozonation and the E-peroxone process substantially reduced the formation of DBPs (trihalomethanes and haloacetic acids) during post-chlorination, higher DBP concentrations were generally observed during chlorination of the E-peroxone pretreated waters than conventional ozonation treated. In addition, because of conventional ozonation or the E-peroxone treatment, DBPs formed during post-chlorination shifted to more brominated species. The overall yields of brominated DBPs exhibited strong correlations with the bromide concentrations in water. Therefore, while the E-peroxone process can effectively suppress bromide transformation to bromate, it may lead to higher formation of brominated DBPs during post-chlorination compared to conventional ozonation. These results suggest that the E-peroxone process can lead to different DBP formation and speciation during water treatment trains compared to conventional ozonation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Evaluation of the stomatal conductance formulation in the EMEP ozone deposition model for Picea abies

    Science.gov (United States)

    Wieser, G.; Emberson, L. D.

    It is widely acknowledged that the possible impacts of ozone on forest trees are more closely related to ozone flux through the stomata than to external ozone exposure. However, the application of the flux approach on a European scale requires the availability of appropriate models, such as the European Monitoring and Evaluation Programme (EMEP) ozone deposition model, for estimating ozone flux and cumulative ozone uptake. Within this model stomatal conductance is the key variable, since it determines the amount of ozone absorbed by the leaves. This paper describes the suitability of the existing EMEP ozone deposition model parameterisation and formulation to represent stomatal behaviour determined from field measurements on adult Norway spruce ( Picea abies (L.) Karst.) trees in the Central European Alps. Parameters affecting maximum stomatal conductance (e.g. seasonal phenology, needle position, needle age, nutrient deficiency and ozone itself) and stomatal response functions to temperature, irradiance, vapour pressure deficit, and soil water content are investigated. Finally, current limitations and possible alterations of the EMEP model will be discussed with respect to spatial scales of available input data for future flux modelling.

  2. Regional and local meteorology influences high-resolution tropospheric ozone concentration in the Los Angeles Basin

    Science.gov (United States)

    Koutzoukis, S.; Jenerette, D.; Chandler, M.; Wang, J.; Ge, C.; Ripplinger, J.

    2017-12-01

    Urban air quality and climate directly affect resident health. The Los Angeles (LA) Basin is a highly populated metropolitan area, with widespread point sources of ozone (O3) precursors (NOx , Volatile Organic Compounds, CO) from fossil fuel combustion. The LA basin exists on a coast-to-mountain gradient, with increasing temperatures towards the Transverse Ranges, which rise to 1700m. Frequently not compliant with 8-hour O3 standards, the LA and South Coast Air Basins are designated as severe and extreme non-attainment areas. Summer weather in the LA basin is characterized by a persistent high pressure system, creating an inversion that traps air pollutants, including O3 precursors, coupled with physical geography that blocks prevailing upper atmosphere air flow. These interactions make neighborhood-level O3 levels more variable than common regional models. Over the summer of 2017, we investigated the importance of local meteorology, wind patterns and air temperature, in transporting and mixing ozone precursors from point sources along the coast-to-mountain gradient. We deployed a network of six EPA federal equivalent method ozone and meteorological sensors in three campaigns in the LA basin along the coast-to-mountain transect. Each campaign, we collaborated with citizen scientists to deploy three sensor stations in two, 4 km2 quadrats, for a total of six high-resolution 4 km2 pixels. O3 concentrations vary greatly along the transect. At the coastal sites, daily O3 ranges from 0ppm to 60ppm and the range increases at the inland sites, to 100ppm. At all sites, there was a positive relationship between wind speed, air temperature, and O3 concentration, with increasing correlation inland. The Pearson correlation coefficient between wind speed and O3 concentration doubles from the coast to inland, and triples between air temperature and O3. The site-specific relationships between O3 and wind direction and temperature vary, suggesting neighborhood-effects from local

  3. Observations and Explicit Modeling of Summertime Carbonyl Formation in Beijing: Identification of Key Precursor Species and Their Impact on Atmospheric Oxidation Chemistry

    Science.gov (United States)

    Yang, Xue; Xue, Likun; Wang, Tao; Wang, Xinfeng; Gao, Jian; Lee, Shuncheng; Blake, Donald R.; Chai, Fahe; Wang, Wenxing

    2018-01-01

    Carbonyls are an important group of volatile organic compounds (VOCs) that play critical roles in tropospheric chemistry. To better understand the formation mechanisms of carbonyl compounds, extensive measurements of carbonyls and related parameters were conducted in Beijing in summer 2008. Formaldehyde (11.17 ± 5.32 ppbv), acetone (6.98 ± 3.01 ppbv), and acetaldehyde (5.27 ± 2.24 ppbv) were the most abundant carbonyl species. Two dicarbonyls, glyoxal (0.68 ± 0.26 ppbv) and methylglyoxal (MGLY; 1.10 ± 0.44 ppbv), were also present in relatively high concentrations. An observation-based chemical box model was used to simulate the in situ production of formaldehyde, acetaldehyde, glyoxal, and MGLY and quantify their contributions to ozone formation and ROx budget. All four carbonyls showed similar formation mechanisms but exhibited different precursor distributions. Alkenes (mainly isoprene and ethene) were the dominant precursors of formaldehyde, while both alkenes (e.g., propene, i-butene, and cis-2-pentene) and alkanes (mainly i-pentane) were major precursors of acetaldehyde. For dicarbonyls, both isoprene and aromatic VOCs were the dominant parent hydrocarbons of glyoxal and MGLY. Photolysis of oxygenated VOCs was the dominant source of ROx radicals (approximately >80% for HO2 and approximately >70% for RO2) in Beijing. Ozone production occurred under a mixed-control regime with carbonyls being the key VOC species. Overall, this study provides some new insights into the formation mechanisms of carbonyls, especially their parent hydrocarbon species, and underlines the important role of carbonyls in radical chemistry and ozone pollution in Beijing. Reducing the emissions of alkenes and aromatics would be an effective way to mitigate photochemical pollution in Beijing.

  4. CONTRIBUTION TO INDOOR OZONE LEVELS OF AN OZONE GENERATOR

    Science.gov (United States)

    This report gives results of a study of a commonly used commercially available ozone generator, undertaken to determine its impact on indoor ozone levels. xperiment were conducted in a typical mechanically ventilated office and in a test house. he generated ozone and the in-room ...

  5. Convection links biomass burning to increased tropical ozone: However, models will tend to overpredict O3

    Science.gov (United States)

    Chatfield, Robert B.; Delany, Anthony C.

    1990-10-01

    Biomass burning throughout the inhabited portions of the tropics generates precursors which lead to significant local atmospheric ozone pollution. Several simulations show how this smog could be only an easily observed, local manifestation of a much broader increase in tropospheric ozone. We illustrate basic processes with a one-dimensional time-dependent model that is closer to true meteorological motions than commonly used eddy diffusion models. Its application to a representative region of South America gives reasonable simulations of the local pollutants measured there. Three illustrative simulations indicate the importance of dilution, principally due to vertical transport, in increasing the efficiency of ozone production, possibly enough for high ozone to be apparent on a very large, intercontinental scale. In the first, cook-then-mix, simulation the nitrogen oxides and other burning-produced pollutants are confined to a persistently subsident fair weather boundary layer for several days, and the resultant ozone is found to have only a transient influence on the whole column of tropospheric ozone. In the second, mix-then-cook, simulation the effect of typical cumulonimbus convection, which vents an actively polluted boundary layer, is to make a persistent increase in the tropical ozone column. Such a broadly increased ozone column is observed over the the populated "continental" portion of the tropics. A third simulation averages all emission, transport, and deposition parameters, representing one column in a global tropospheric model that does not simulate individual weather events. This "oversmoothing" simulation produces 60% more ozone than observed or otherwise modeled. Qualitatively similar overprediction is suggested for all models which average significantly in time or space, as all need do. Clearly, simulating these O3 levels will depend sensitively on knowledge of the timing of emissions and transport.

  6. Development of Compact Ozonizer with High Ozone Output by Pulsed Power

    Science.gov (United States)

    Tanaka, Fumiaki; Ueda, Satoru; Kouno, Kanako; Sakugawa, Takashi; Akiyama, Hidenori; Kinoshita, Youhei

    Conventional ozonizer with a high ozone output using silent or surface discharges needs a cooling system and a dielectric barrier, and therefore becomes a large machine. A compact ozonizer without the cooling system and the dielectric barrier has been developed by using a pulsed power generated discharge. The wire to plane electrodes made of metal have been used. However, the ozone output was low. Here, a compact and high repetition rate pulsed power generator is used as an electric source of a compact ozonizer. The ozone output of 6.1 g/h and the ozone yield of 86 g/kWh are achieved at 500 pulses per second, input average power of 280 W and an air flow rate of 20 L/min.

  7. Evaluation of The Surface Ozone Concentrations In Greater Cairo Area With Emphasis On Helwan, Egypt

    International Nuclear Information System (INIS)

    Ramadan, A.; Kandil, A.T.; Abd Elmaged, S.M.; Mubarak, I.

    2011-01-01

    Various biogenic and anthropogenic sources emit huge quantities of surface ozone. The main purpose of this study is to evaluate the surface ozone levels present at Helwan area in order to improve the knowledge and understanding troposphere processes. Surface Ozone has been measured at 2 sites at Helwan; these sites cover the most populated area in Helwan. Ozone concentration is continuously monitored by UV absorption photometry using the equipment O 3 41 M UV Photometric Ozone Analyzer. The daily maximum values of the ozone concentration in the greater Cairo area have approached but did not exceeded the critical levels during the year 2008. Higher ozone concentrations at Helwan are mainly due to the transport of ozone from regions further to the north of greater Cairo and to a lesser extent of ozone locally generated by photochemical smog process. The summer season has the largest diurnal variation, with the tendency of the daily ozone maxima occur in the late afternoon. The night time concentration of ozone was significantly higher at Helwan because there are no fast acting sinks, destroying ozone since the average night time concentration of ozone is maintained at 40 ppb at the site. No correlation between the diurnal total suspended particulate (TSP) matter and the diurnal cumulative ozone concentration was observed during the Khamasin period

  8. 20 Years of Total and Tropical Ozone Time Series Based on European Satellite Observations

    Science.gov (United States)

    Loyola, D. G.; Heue, K. P.; Coldewey-Egbers, M.

    2016-12-01

    Ozone is an important trace gas in the atmosphere, while the stratospheric ozone layer protects the earth surface from the incident UV radiation, the tropospheric ozone acts as green house gas and causes health damages as well as crop loss. The total ozone column is dominated by the stratospheric column, the tropospheric columns only contributes about 10% to the total column.The ozone column data from the European satellite instruments GOME, SCIAMACHY, OMI, GOME-2A and GOME-2B are available within the ESA Climate Change Initiative project with a high degree of inter-sensor consistency. The tropospheric ozone columns are based on the convective cloud differential algorithm. The datasets encompass a period of more than 20 years between 1995 and 2015, for the trend analysis the data sets were harmonized relative to one of the instruments. For the tropics we found an increase in the tropospheric ozone column of 0.75 ± 0.12 DU decade^{-1} with local variations between 1.8 and -0.8. The largest trends were observed over southern Africa and the Atlantic Ocean. A seasonal trend analysis led to the assumption that the increase is caused by additional forest fires.The trend for the total column was not that certain, based on model predicted trend data and the measurement uncertainty we estimated that another 10 to 15 years of observations will be required to observe a statistical significant trend. In the mid latitudes the trends are currently hidden in the large variability and for the tropics the modelled trends are low. Also the possibility of diverging trends at different altitudes must be considered; an increase in the tropospheric ozone might be accompanied by decreasing stratospheric ozone.The European satellite data record will be extended over the next two decades with the atmospheric satellite missions Sentinel 5 Precursor (launch end of 2016), Sentinel 4 and Sentinel 5.

  9. Influence of low ozone episodes on erythemal UV-B radiation in Austria

    Science.gov (United States)

    Schwarz, Matthias; Baumgartner, Dietmar J.; Pietsch, Helga; Blumthaler, Mario; Weihs, Philipp; Rieder, Harald E.

    2017-06-01

    This study investigates the influence of low ozone episodes on UV-B radiation in Austria during the period 1999 to 2015. To this aim observations of total column ozone (TCO) in the Greater Alpine Region (Arosa, Switzerland; Hohenpeissenberg, Germany; Hradec Kralove, Czech Republic; Sonnblick, Austria), and erythemal UV-B radiation, available from 12 sites of the Austrian UV-B monitoring network, are analyzed. As previous definitions for low ozone episodes are not particularly suited to investigate effects on UV radiation, a novel threshold approach—considering anomalies—is developed to provide a joint framework for the analysis of extremes. TCO and UV extremes are negatively correlated, although modulating effects of sunshine duration impact the robustness of the statistical relationship. Therefore, information on relative sunshine duration (SDrel), available at (or nearby) UV-B monitoring sites, is included as explanatory variable in the analysis. The joint analysis of anomalies of both UV index (UVI) and total ozone (∆UVI, ∆TCO) and SDrel across sites shows that more than 65% of observations with strongly negative ozone anomalies (∆TCO 1), we find (across all sites) that about 90% correspond to negative ∆TCO. The remaining 10% of days occurred during fair weather conditions (SDrel ≥ 80%) explaining the appearance of ∆UVI > 1 despite positive TCO anomalies. Further, we introduce an anomaly amplification factor (AAF), which quantifies the expected change of the ∆UVI for a given change in ∆TCO.

  10. Secondary maxima in ozone profiles

    Directory of Open Access Journals (Sweden)

    R. Lemoine

    2004-01-01

    Full Text Available Ozone profiles from balloon soundings as well as SAGEII ozone profiles were used to detect anomalous large ozone concentrations of ozone in the lower stratosphere. These secondary ozone maxima are found to be the result of differential advection of ozone-poor and ozone-rich air associated with Rossby wave breaking events. The frequency and intensity of secondary ozone maxima and their geographical distribution is presented. The occurrence and amplitude of ozone secondary maxima is connected to ozone variability and trend at Uccle and account for a large part of the total ozone and lower stratospheric ozone variability.

  11. First Reprocessing of Southern Hemisphere Additional Ozonesondes (SHADOZ) Ozone Profiles (1998-2016): 2. Comparisons With Satellites and Ground-Based Instruments

    Science.gov (United States)

    Thompson, Anne M.; Witte, Jacquelyn C.; Sterling, Chance; Jordan, Allen; Johnson, Bryan J.; Oltmans, Samuel J.; Fujiwara, Masatomo; Vömel, Holger; Allaart, Marc; Piters, Ankie; Coetzee, Gert J. R.; Posny, Françoise; Corrales, Ernesto; Diaz, Jorge Andres; Félix, Christian; Komala, Ninong; Lai, Nga; Ahn Nguyen, H. T.; Maata, Matakite; Mani, Francis; Zainal, Zamuna; Ogino, Shin-ya; Paredes, Francisco; Penha, Tercio Luiz Bezerra; da Silva, Francisco Raimundo; Sallons-Mitro, Sukarni; Selkirk, Henry B.; Schmidlin, F. J.; Stübi, Rene; Thiongo, Kennedy

    2017-12-01

    The Southern Hemisphere ADditional OZonesonde (SHADOZ) network was assembled to validate a new generation of ozone-monitoring satellites and to better characterize the vertical structure of tropical ozone in the troposphere and stratosphere. Beginning with nine stations in 1998, more than 7,000 ozone and P-T-U profiles are available from 14 SHADOZ sites that have operated continuously for at least a decade. We analyze ozone profiles from the recently reprocessed SHADOZ data set that is based on adjustments for inconsistencies caused by varying ozonesonde instruments and operating techniques. First, sonde-derived total ozone column amounts are compared to the overpasses from the Earth Probe/Total Ozone Mapping Spectrometer, Ozone Monitoring Instrument, and Ozone Mapping and Profiler Suite satellites that cover 1998-2016. Second, characteristics of the stratospheric and tropospheric columns are examined along with ozone structure in the tropical tropopause layer (TTL). We find that (1) relative to our earlier evaluations of SHADOZ data, in 2003, 2007, and 2012, sonde-satellite total ozone column offsets at 12 stations are 2% or less, a significant improvement; (2) as in prior studies, the 10 tropical SHADOZ stations, defined as within ±19° latitude, display statistically uniform stratospheric column ozone, 229 ± 3.9 DU (Dobson units), and a tropospheric zonal wave-one pattern with a 14 DU mean amplitude; (3) the TTL ozone column, which is also zonally uniform, masks complex vertical structure, and this argues against using satellites for lower stratospheric ozone trends; and (4) reprocessing has led to more uniform stratospheric column amounts across sites and reduced bias in stratospheric profiles. As a consequence, the uncertainty in total column ozone now averages 5%.

  12. The stratospheric ozone and the ozone layer

    International Nuclear Information System (INIS)

    Zea Mazo, Jorge Anibal; Leon Aristizabal Gloria Esperanza; Eslava Ramirez Jesus Antonio

    2000-01-01

    An overview is presented of the principal characteristics of the stratospheric ozone in the Earth's atmosphere, with particular emphasis on the tropics and the ozone hole over the poles. Some effects produced in the atmosphere as a consequence of the different human activities will be described, and some data on stratospheric ozone will be shown. We point out the existence of a nucleus of least ozone in the tropics, stretching from South America to central Africa, with annual mean values less than 240 DU, a value lower than in the middle latitudes and close to the mean values at the South Pole. The existence of such a minimum is confirmed by mean values from measurements made on satellites or with earthbound instruments, for different sectors in Colombia, like Medellin, Bogota and Leticia

  13. Evaluation of the Ozone Fields in NASA’s MERRA-2 Reanalysis

    Science.gov (United States)

    Wargan, Krzysztof; Labow, Gordon; Frith, Stacey; Pawson, Steven; Livesey, Nathaniel; Partyka, Gary

    2018-01-01

    We describe and assess the quality of the assimilated ozone product from the Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA-2) produced at NASA’s Global Modeling and Assimilation Office (GMAO) spanning the time period from 1980 to present. MERRA-2 assimilates partial column ozone retrievals from a series of Solar Backscatter Ultraviolet (SBUV) radiometers on NASA and NOAA spacecraft between January 1980 and September 2004; starting in October 2004 retrieved ozone profiles from the Microwave Limb Sounder (MLS) and total column ozone from the Ozone Monitoring Instrument on NASA’s EOS Aura satellite are assimilated. We compare the MERRA-2 ozone with independent satellite and ozonesonde data focusing on the representation of the spatial and temporal variability of stratospheric and upper tropospheric ozone and on implications of the change in the observing system from SBUV to EOS Aura. The comparisons show agreement within 10 % (standard deviation of the difference) between MERRA-2 profiles and independent satellite data in most of the stratosphere. The agreement improves after 2004 when EOS Aura data are assimilated. The standard deviation of the differences between the lower stratospheric and upper tropospheric MERRA-2 ozone and ozonesondes is 11.2 % and 24.5 %, respectively, with correlations of 0.8 and above, indicative of a realistic representation of the near-tropopause ozone variability in MERRA-2. The agreement improves significantly in the EOS Aura period, however MERRA-2 is biased low in the upper troposphere with respect to the ozonesondes. Caution is recommended when using MERRA-2 ozone for decadal changes and trend studies. PMID:29527096

  14. Retrieval of Surface Ozone from UV-MFRSR Irradiances using Deep Learning

    Science.gov (United States)

    Chen, M.; Sun, Z.; Davis, J.; Zempila, M.; Liu, C.; Gao, W.

    2017-12-01

    High concentration of surface ozone is harmful to humans and plants. USDA UV-B Monitoring and Research Program (UVMRP) uses Ultraviolet (UV) version of Multi-Filter Rotating Shadowband Radiometer (UV-MFRSR) to measure direct, diffuse, and total irradiances every three minutes at seven UV channels (i.e. 300, 305, 311, 317, 325, 332, and 368 nm channels with 2 nm full width at half maximum). Based on the wavelength dependency of aerosol optical depths, there have been plenty of literatures exploring retrieval methods of total column ozone from UV-MFRSR measurements. However, few has explored the retrieval of surface ozone. The total column ozone is the integral of the multiplication of ozone concentration (varying by height and time) and cross section (varying by wavelength and temperature) over height. Because of the distinctive values of ozone cross section in the UV region, the irradiances at seven UV channels have the potential to resolve the ozone concentration at multiple vertical layers. If the UV irradiances at multiple time points are considered together, the uncertainty or the vertical resolution of ozone concentrations can be further improved. In this study, the surface ozone amounts at the UVMRP station located at Billings, Oklahoma are estimated from the adjacent (i.e. within 200 miles) US Environmental Protection Agency (EPA) surface ozone observations using the spatial analysis technique. Then, the (direct normal) irradiances of UVMRP at one or more time points as inputs and the corresponding estimated surface ozone from EPA as outputs are fed into a pre-trained (dense) deep neural network (DNN) to explore the hidden non-linear relationship between them. This process could improve our understanding of their physical/mathematical relationship. Finally, the optimized DNN is tested with the preserved 5% of the dataset, which are not used during training, to verify the relationship.

  15. Ozonation of azo dyes (Orange II and Acid Red 27) in saline media

    International Nuclear Information System (INIS)

    Silva, Alessandra C.; Pic, Jean Stephane; Sant'Anna, Geraldo L.; Dezotti, Marcia

    2009-01-01

    Ozonation of two azo dyes was investigated in a monitored bench scale bubble column reactor (8.5-L), varying liquid media salt content (0, 1, 40 and 100 g L -1 , NaCl). In experiments with Orange II pH was varied (5, 7.5 and 9) but ozonation of Acid Red 27 was performed at pH 7.5. Ozone self-decomposition rate-constant increased with salt concentration. Color removal was very effective and fast achieved under all experimental conditions. For the two azo dyes tested, more than 98% of color intensity was removed in 30-min ozonation assays. However, only partial mineralization of azo dyes (45%-Orange II; 20%-Acid Red 27) was attained in such experiments. The degree of mineralization (TOC removal) was negatively affected by salt concentration. Biodegradation assays conducted by respirometry revealed the inhibitory effect of dye degradation products formed during ozonation.

  16. [Zr(NEtMe)2(guan-NEtMe)2] as a novel ALD precursor: ZrO2 film growth and mechanistic studies

    NARCIS (Netherlands)

    Blanquart, T.; Niinistö, J.; Aslam, N.; Banerjee, M.; Tomczak, Y.; Gavagnin, M.; Longo, V.; Puukilainen, E.; Wanzenboeck, H.D.; Kessels, W.M.M.; Devi, A.; Hoffmann-Eifert, S.; Ritala, M.; Leskelä, M.

    2013-01-01

    [Zr(NEtMe)2(guan-NEtMe2)2], a recently developed compound, was investigated as a novel precursor for the atomic layer deposition (ALD) of ZrO2. With water as the oxygen source, the growth rate remained constant over a wide temperature range, whereas with ozone the growth rate increased steadily with

  17. A comparative analysis of UV nadir-backscatter and infrared limb-emission ozone data assimilation

    Directory of Open Access Journals (Sweden)

    R. Dragani

    2016-07-01

    Full Text Available This paper presents a comparative assessment of ultraviolet nadir-backscatter and infrared limb-emission ozone profile assimilation. The Meteorological Operational Satellite A (MetOp-A Global Ozone Monitoring Experiment 2 (GOME-2 nadir and the ENVISAT Michelson Interferometer for Passive Atmospheric Sounding (MIPAS limb profiles, generated by the ozone consortium of the European Space Agency Climate Change Initiative (ESA O3-CCI, were individually added to a reference set of ozone observations and assimilated in the European Centre for Medium-Range Weather Forecasts (ECMWF data assimilation system (DAS. The two sets of resulting analyses were compared with that from a control experiment, only constrained by the reference dataset, and independent, unassimilated observations. Comparisons with independent observations show that both datasets improve the stratospheric ozone distribution. The changes inferred by the limb-based observations are more localized and, in places, more important than those implied by the nadir profiles, albeit they have a much lower number of observations. A small degradation (up to 0.25 mg kg−1 for GOME-2 and 0.5 mg kg−1 for MIPAS in the mass mixing ratio is found in the tropics between 20 and 30 hPa. In the lowermost troposphere below its vertical coverage, the limb data are found to be able to modify the ozone distribution with changes as large as 60 %. Comparisons of the ozone analyses with sonde data show that at those levels the assimilation of GOME-2 leads to about 1 Dobson Unit (DU smaller root mean square error (RMSE than that of MIPAS. However, the assimilation of MIPAS can still improve the quality of the ozone analyses and – with a reduction in the RMSE of up to about 2 DU – outperform the control experiment thanks to its synergistic assimilation with total-column ozone data within the DAS. High vertical resolution ozone profile observations are essential to accurately monitor and

  18. Tropospheric Column Ozone Response to ENSO in GEOS-5 Assimilation of OMI and MLS Ozone Data

    Science.gov (United States)

    Olsen, Mark A.; Wargan, Krzysztof; Pawson, Steven

    2016-01-01

    We use GEOS-5 analyses of Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) ozone observations to investigate the magnitude and spatial distribution of the El Nino Southern Oscillation (ENSO) influence on tropospheric column ozone (TCO) into the middle latitudes. This study provides the first explicit spatially resolved characterization of the ENSO influence and demonstrates coherent patterns and teleconnections impacting the TCO in the extratropics. The response is evaluated and characterized by both the variance explained and sensitivity of TCO to the Nino 3.4 index. The tropospheric response in the tropics agrees well with previous studies and verifies the analyses. A two-lobed response symmetric about the Equator in the western Pacific/Indonesian region seen in some prior studies and not in others is confirmed here. This two-lobed response is consistent with the large-scale vertical transport. We also find that the large-scale transport in the tropics dominates the response compared to the small-scale convective transport. The ozone response is weaker in the middle latitudes, but a significant explained variance of the TCO is found over several small regions, including the central United States. However, the sensitivity of TCO to the Nino 3.4 index is statistically significant over a large area of the middle latitudes. The sensitivity maxima and minima coincide with anomalous anti-cyclonic and cyclonic circulations where the associated vertical transport is consistent with the sign of the sensitivity. Also, ENSO related changes to the mean tropopause height can contribute significantly to the midlatitude response. Comparisons to a 22-year chemical transport model simulation demonstrate that these results from the 9- year assimilation are representative of the longer term. This investigation brings insight to several seemingly disparate prior studies of the El Nino influence on tropospheric ozone in the middle latitudes.

  19. Tropospheric column ozone response to ENSO in GEOS-5 assimilation of OMI and MLS ozone data

    Directory of Open Access Journals (Sweden)

    M. A. Olsen

    2016-06-01

    Full Text Available We use GEOS-5 analyses of Ozone Monitoring Instrument (OMI and Microwave Limb Sounder (MLS ozone observations to investigate the magnitude and spatial distribution of the El Niño Southern Oscillation (ENSO influence on tropospheric column ozone (TCO into the middle latitudes. This study provides the first explicit spatially resolved characterization of the ENSO influence and demonstrates coherent patterns and teleconnections impacting the TCO in the extratropics. The response is evaluated and characterized by both the variance explained and sensitivity of TCO to the Niño 3.4 index. The tropospheric response in the tropics agrees well with previous studies and verifies the analyses. A two-lobed response symmetric about the Equator in the western Pacific/Indonesian region seen in some prior studies and not in others is confirmed here. This two-lobed response is consistent with the large-scale vertical transport. We also find that the large-scale transport in the tropics dominates the response compared to the small-scale convective transport. The ozone response is weaker in the middle latitudes, but a significant explained variance of the TCO is found over several small regions, including the central United States. However, the sensitivity of TCO to the Niño 3.4 index is statistically significant over a large area of the middle latitudes. The sensitivity maxima and minima coincide with anomalous anti-cyclonic and cyclonic circulations where the associated vertical transport is consistent with the sign of the sensitivity. Also, ENSO related changes to the mean tropopause height can contribute significantly to the midlatitude response. Comparisons to a 22-year chemical transport model simulation demonstrate that these results from the 9-year assimilation are representative of the longer term. This investigation brings insight to several seemingly disparate prior studies of the El Niño influence on tropospheric ozone in the middle latitudes.

  20. Earth's ozone layer

    International Nuclear Information System (INIS)

    Lasa, J.

    1991-01-01

    The paper contain the actual results of investigations of the influence of the human activity on the Earth's ozone layer. History of the ozone measurements and of the changes in its concentrations within the last few years are given. The influence of the trace gases on both local and global ozone concentrations are discussed. The probable changes of the ozone concentrations are presented on the basis of the modelling investigations. The effect of a decrease in global ozone concentration on human health and on biosphere are also presented. (author). 33 refs, 36 figs, 5 tabs

  1. Urban Summertime Ozone of China: Peak Ozone Hour and Nighttime Mixing

    Science.gov (United States)

    Qu, H.; Wang, Y.; Zhang, R.

    2017-12-01

    We investigate the observed diurnal cycle of summertime ozone in the cities of China using a regional chemical transport model. The simulated daytime ozone is in general agreement with the observations. Model simulations suggest that the ozone peak time and peak concentration are a function of NOx (NO + NO2) and volatile organic compound (VOC) emissions. The differences between simulated and observed ozone peak time and peak concentration in some regions can be applied to understand biases in the emission inventories. For example, the VOCs emissions are underestimated over the Pearl River Delta (PRD) region, and either NOx emissions are underestimated or VOC emissions are overestimated over the Yangtze River Delta (YRD) regions. In contrast to the general good daytime ozone simulations, the simulated nighttime ozone has a large low bias of up to 40 ppbv. Nighttime ozone in urban areas is sensitive to the nocturnal boundary-layer mixing, and enhanced nighttime mixing (from the surface to 200-500 m) is necessary for the model to reproduce the observed level of ozone.

  2. Total ozone changes in the 1987 Antarctic ozone hole

    Science.gov (United States)

    Krueger, Arlin J.; Schoeberl, Mark R.; Doiron, Scott D.; Sechrist, Frank; Galimore, Reginald

    1988-01-01

    The development of the Antarctic ozone minimum was observed in 1987 with the Nimbus 7 Total Ozone Mapping Spectrometer (TOMS) instrument. In the first half of August the near-polar (60 and 70 deg S) ozone levels were similar to those of recent years. By September, however, the ozone at 70 and 80 deg S was clearly lower than any previous year including 1985, the prior record low year. The levels continued to decrease throughout September until October 5 when a new record low of 109 DU was established at a point near the South Pole. This value is 29 DU less than the lowest observed in 1985 and 48 DU less than the 1986 low. The zonal mean total ozone at 60 deg S remained constant throughout the time of ozone hole formation. The ozone decline was punctuated by local minima formed away from the polar night boundary at about 75 deg S. The first of these, on August 15 to 17, formed just east of the Palmer Peninsula and appears to be a mountain wave. The second major minimum formed on September 5 to 7 again downwind of the Palmer Peninsula. This event was larger in scale than the August minimum and initiated the decline of ozone across the polar region. The 1987 ozone hole was nearly circular and pole centered for its entire life. In previous years the hole was perturbed by intrusions of the circumpolar maximum into the polar regions, thus causing the hole to be elliptical. The 1987 hole also remained in place until the end of November, a few days longer than in 1985, and this persistence resulted in the latest time for recovery to normal values yet observed.

  3. Ozonation control and effects of ozone on water quality in recirculating aquaculture systems

    DEFF Research Database (Denmark)

    Spiliotopoulou, Aikaterini; Rojas-Tirado, Paula Andrea; Chetri, Ravi K.

    2018-01-01

    To address the undesired effect of chemotherapeutants in aquaculture, ozone has been suggested as an alternative to improve water quality. To ensure safe and robust treatment, it is vital to define the ozone demand and ozone kinetics of the specific water matrix to avoid ozone overdose. Different...... ozone dosages were applied to water in freshwater recirculating aquaculture systems (RAS). Experiments were performed to investigate ozone kinetics and demand, and to evaluate the effects on the water quality, particularly in relation to fluorescent organic matter. This study aimed at predicting...... a suitable ozone dosage for water treatment based on daily ozone demand via laboratory studies. These ozone dosages will be eventually applied and maintained at these levels in pilot-scale RAS to verify predictions. Selected water quality parameters were measured, including natural fluorescence and organic...

  4. Measurements and Mesoscale Modeling of Autumnal Vertical Ozone Profiles in Southern Taiwan

    Directory of Open Access Journals (Sweden)

    Yen-Ping Peng

    2008-01-01

    Full Text Available Vertical measurements of ozone were made using a tethered balloon at the Linyuan site in Kaohsiung County, southern Taiwan. Ozone was monitored at altitudes of 0, 100, 300, 500, and 1000 m from November 23 to 25 in 2005. The potential temperature profiles revealed a stable atmosphere during the study period, largely because of the dominance of the high-pressure system and nocturnal radiation cooling close to the surface. The mixing height was low (50 - 300 m, particularly in the late night and early morning. The surface ozone concentrations that were predicted using TAPM (The Air Pollution Model were high (33.7 - 119 ppbv in the daytime (10:00 - 16:00 and were low (10 - 40 ppbv at other times; the predictions of which were consistent with the observations. The simulated surface ozone concentrations reveal that costal lands typically had higher ozone concentrations than those inland, because most industrial parks are located in or close to the boundaries of Kaohsiung City. Both measurements and simulations indicate that daytime ozone concentrations decreased quickly with increasing height at altitudes below 300 m; while nighttime ozone concentrations were lower at low altitudes (50 to 300 m than at higher altitudes, partly because of dry deposition and titration of surface ozone by the near-surface nitrogen oxides (NOx and partly because of the existence of the residual layer above the stable nocturnal boundary layer. The simulations show a good correlation between the maximum daytime surface ozone concentration and average nighttime ozone concentration above the nocturnal boundary layer.

  5. Ozone modeling

    International Nuclear Information System (INIS)

    McIllvaine, C.M.

    1994-01-01

    Exhaust gases from power plants that burn fossil fuels contain concentrations of sulfur dioxide (SO 2 ), nitric oxide (NO), particulate matter, hydrocarbon compounds and trace metals. Estimated emissions from the operation of a hypothetical 500 MW coal-fired power plant are given. Ozone is considered a secondary pollutant, since it is not emitted directly into the atmosphere but is formed from other air pollutants, specifically, nitrogen oxides (NO), and non-methane organic compounds (NMOQ) in the presence of sunlight. (NMOC are sometimes referred to as hydrocarbons, HC, or volatile organic compounds, VOC, and they may or may not include methane). Additionally, ozone formation Alternative is a function of the ratio of NMOC concentrations to NO x concentrations. A typical ozone isopleth is shown, generated with the Empirical Kinetic Modeling Approach (EKMA) option of the Environmental Protection Agency's (EPA) Ozone Isopleth Plotting Mechanism (OZIPM-4) model. Ozone isopleth diagrams, originally generated with smog chamber data, are more commonly generated with photochemical reaction mechanisms and tested against smog chamber data. The shape of the isopleth curves is a function of the region (i.e. background conditions) where ozone concentrations are simulated. The location of an ozone concentration on the isopleth diagram is defined by the ratio of NMOC and NO x coordinates of the point, known as the NMOC/NO x ratio. Results obtained by the described model are presented

  6. The use of ozone in an artificial seawater environment and its ability to degrade Gymnodinium breve toxins

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, K.R.

    1991-01-01

    The objectives of this research were to establish the practicality of currently used oxidant tests for ozone-treated artificial seawater and to determine the effectiveness of using ozone to reduce toxins associated with Gymnodinium breve, the red tide-causing dinoflagellate found in the Gulf of Mexico off the coast of Florida. In addition to its beneficial role, some emphasis was placed on ascertaining if any harmful by-products could be formed during the ozonation process. Three tests using amperometric titration, potassium iodide (KI) and N,N-diethyl-p-phenylene-diamine (DPD) were performed to determine their ability to detect ozone-produced oxidants in various solutions. These methods yielded different results when bromine and ammonia concentrations were varied in an artificial seawater (ASW) environment. The KI test yielded up to 100 percent higher estimates for each sample than did the amperometric and DPD tests. To test for the possible production of harmful by-products during the ozonation process, ASW samples were spiked with 1 gram of hesperetin. In experiments where the seawater mix was exposed to 27 ppm of ozone prior to the introduction of the organic precursor, small but measurable amounts of tribromomethane were detected via gas chromatography/mass spectroscopy. As the ozone dose was increased to 135 ppm, the recoverable levels of tribromomethane increased. When G. breve toxins were exposed to ozone treatment, samples displayed a three log reduction in the total amount of toxin recovered after ten minutes. Reduction in toxin levels directly correlated with reduction of toxicity as determined by a fish bioassay. It is significant to report that even after 10 minutes of ozonation, comparable to dose levels of that might be used in a commercial depuration facility, some toxins were still recoverable by HPLC analysis.

  7. Impact of near-surface atmospheric composition on ozone formation in Russia

    Science.gov (United States)

    Berezina, Elena; Moiseenko, Konstantin; Skorokhod, Andrey; Belikov, Igor; Pankratova, Natalia; Elansky, Nikolai

    2017-04-01

    One of the consequences of the human impact on the atmosphere is increasing in tropospheric ozone concentration, with the highest ozone level being observed in industrially developed and highly populated regions of the world. In these regions, main anthropogenic sources of carbon monoxide (CO), methane (CH4) and volatile organic compounds (VOCs) are concentrated. The oxidation of these compounds, when interacting with hydroxyl and nitrogen oxides at rather high temperature and sunlight, leads to ozone formation. CO and CH4 are slowly oxidized in the atmosphere and cause an increase in global and regional background ozone. However, the oxidation of some VOCs occurs during daylight hours and is accompanied by an increase in ozone concentration near VOCs sources, particularly in urban and industrial areas. The contribution of biogenic VOCs to ozone generation is estimated to be from 40 to 70% of the total contribution of all chemical ozone precursors in the troposphere [1], with isoprene playing the main role in ozone formation [2]. The impact of aromatic hydrocarbons to ozone formation is reported to be about 40% of the total ozone generation from the oxidation of anthropogenic VOCs [3]. In this study, the results of VOCs measurements (isoprene, benzene, toluene, phenol, styrene, xylene and propilbenzene) by proton mass spectrometry in different regions of Russia along the Trans-Siberian railway from Moscow to Vladivostok from TROICA-12 campaign on a mobile laboratory in summer 2008 are analyzed. It is shown that the TROICA-12 measurements were carried out mostly in moderately polluted (2≤NOx20 ppb) conditions ( 20 and 2% of measurements, correspondingly). The lower troposphere chemical regime in the campaign is found to be mainly NOx sensitive, both in rural and urban environments, with typical morning NMHC/NOx ratios being well above 20. Hence, ozone production rates are expected to be controlled by regional NOx emissions and their complex interplay with both

  8. Measures of ozone concentrations using passive sampling in forests of South Western Europe

    Energy Technology Data Exchange (ETDEWEB)

    Sanz, M.J. [Fundacion CEAM, Charles R. Darwin 14, Parc Tecnologic, E-46980 Paterna, Valencia (Spain)]. E-mail: mjose@ceam.es; Calatayud, V. [Fundacion CEAM, Charles R. Darwin 14, Parc Tecnologic, E-46980 Paterna, Valencia (Spain); Sanchez-Pena, G. [Servicio de Proteccion de los Montes contra Agentes Nocivos, Direccion General para la Biodiversidad, Ministerio de Medio Ambiente, Gran Via de San Francisco, 4, E-28005, Madrid (Spain)

    2007-02-15

    Ambient ozone concentrations were measured with passive samplers in the framework of the EU and UN/ECE Level II forest monitoring programme. Data from France, Italy, Luxembourg, Spain and Switzerland are reported for 2000-2002, covering the period from April to September. The number of plots increased from 67 in 2000 to 83 in 2002. The year 2001 experienced the highest ozone concentrations, reflecting more stable summer meteorological conditions. Average 6-month ozone concentrations above 45 ppb were measured this year in 40.3% of the plots, in contrast with the less than 21% measured in the other 2 years. Gradients of increasing ozone levels were observed from North to South and with altitude. Comments are made on the regional trends and on the time frame of the higher ozone episodes. Also, some recommendations enabling a better comparison between plots are provided. - Ozone concentrations in forested areas of SW Europe during the period 2000-2002 showed highest values in 2001, as well as a tendency to increase towards the South and with altitude.

  9. Measures of ozone concentrations using passive sampling in forests of South Western Europe

    International Nuclear Information System (INIS)

    Sanz, M.J.; Calatayud, V.; Sanchez-Pena, G.

    2007-01-01

    Ambient ozone concentrations were measured with passive samplers in the framework of the EU and UN/ECE Level II forest monitoring programme. Data from France, Italy, Luxembourg, Spain and Switzerland are reported for 2000-2002, covering the period from April to September. The number of plots increased from 67 in 2000 to 83 in 2002. The year 2001 experienced the highest ozone concentrations, reflecting more stable summer meteorological conditions. Average 6-month ozone concentrations above 45 ppb were measured this year in 40.3% of the plots, in contrast with the less than 21% measured in the other 2 years. Gradients of increasing ozone levels were observed from North to South and with altitude. Comments are made on the regional trends and on the time frame of the higher ozone episodes. Also, some recommendations enabling a better comparison between plots are provided. - Ozone concentrations in forested areas of SW Europe during the period 2000-2002 showed highest values in 2001, as well as a tendency to increase towards the South and with altitude

  10. Aviation-attributable ozone as a driver for changes in mortality related to air quality and skin cancer

    Science.gov (United States)

    Eastham, Sebastian D.; Barrett, Steven R. H.

    2016-11-01

    Aviation is a significant source of tropospheric ozone, which is a critical UV blocking agent, an indirect precursor to the formation of particulate matter, and a respiratory health hazard. To date, investigations of human health impacts related to aviation emissions have focused on particulate matter, and no global estimate yet exists of the combined health impact of aviation due to ozone, particulate matter and UV exposure changes. We use a coupled tropospheric-stratospheric chemical-transport model with a global aviation emissions inventory to estimate the total impact of aviation on all three risk factors. We find that surface ozone due to aviation emissions is maximized during hemispheric winter due to the greater wintertime chemical lifetime of ozone, but that a smaller enhancement of 0.5 ppbv occurs during summertime. This summertime increase results in an estimated 6,800 premature mortalities per year due to ozone exposure, over three times greater than previous estimates. During the winter maximum, interaction with high background NOx concentrations results in enhanced production of nitrate aerosol and increased annual average exposure to particulate matter. This ozone perturbation is shown to be the driving mechanism behind an additional 9,200 premature mortalities due to exposure to particulate matter. However, the increase in tropospheric ozone is also found to result in 400 fewer mortalities due to melanoma skin cancer in 2006. This is the first estimate of global melanoma mortality due to aviation, and the first estimate of skin cancer mortality impacts due to aviation using a global chemical transport model.

  11. Unraveling the sources of ground level ozone in the Intermountain Western United States using Pb isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, John N. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Weiss-Penzias, Peter [University of California at Santa Cruz, Santa Cruz, CA (United States); Fine, Rebekka [University of Nevada, Reno, NV (United States); McDade, Charles E.; Trzepla, Krystyna [University of California at Davis, Crocker Nuclear Laboratory, Davis, CA (United States); Brown, Shaun T. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Gustin, Mae Sexauer [University of Nevada, Reno, NV (United States)

    2015-10-15

    Ozone as an atmospheric pollutant is largely produced by anthropogenic precursors and can significantly impact human and ecosystem health, and climate. The U.S. Environmental Protection Agency has recently proposed lowering the ozone standard from 75 ppbv (MDA8 = Maximum Daily 8-Hour Average) to between 65 and 70 ppbv. This will result in remote areas of the Intermountain West that includes many U.S. National Parks being out of compliance, despite a lack of significant local sources. We used Pb isotope fingerprinting and back-trajectory analysis to distinguish sources of imported ozone to Great Basin National Park in eastern Nevada. During discrete Chinese Pb events (> 1.1 ng/m{sup 3} & > 80% Asian Pb) trans-Pacific transported ozone was 5 ± 5.5 ppbv above 19 year averages for those dates. In contrast, concentrations during regional transport from the Los Angeles and Las Vegas areas were 15 ± 2 ppbv above the long-term averages, and those characterized by high-altitude transport 3 days prior to sampling were 19 ± 4 ppbv above. However, over the study period the contribution of trans-Pacific transported ozone increased at a rate of 0.8 ± 0.3 ppbv/year, suggesting that Asian inputs will exceed regional and high altitude sources by 2015–2020. All of these sources will impact regulatory compliance with a new ozone standard, given increasing global background. - Highlights: • Ozone can significantly impact human and ecosystem health and climate. • Pb isotopes and back-trajectory analysis were used to distinguish sources of O{sub 3}. • Baseline concentrations in the Western US are ~ 54 ppbv. • During discrete Asia events O{sub 3} increased by 5 ± 5.5 ppbv and during S CA events by 15 ± 2 ppbv. • Data indicate that Asian ozone inputs will exceed other sources by 2015–2020.

  12. OMI/Aura Ozone (O3) Total Column 1-Orbit L2 Swath 13x24 km V003 NRT

    Data.gov (United States)

    National Aeronautics and Space Administration — The OMI/Aura Level-2 Total Column Ozone Data Product OMTO3 Near Real Time data is made available from the OMI SIPS NASA for the public access. The Ozone Monitoring...

  13. Observation of stratospheric ozone with NIES lidar system in Tsukuba, Japan

    International Nuclear Information System (INIS)

    Nakane, H.; Hayashida, S.; Sasano, Y.; Sugimoto, N.; Matsui, I.; Minato, A.

    1992-01-01

    Lidars are expected to play important roles in an international monitoring network of the stratosphere such as the Network for the Detection of Stratospheric Change (NDSC). The National Institute for Environmental Studies (NIES) in Tsukuba constructed an ozone lidar system in March 1988 and started observation in August 1988. The lidar system has a 2-m telescope and injection locked XeCl and XeF excimer lasers which can measure ozone profiles (15-45 km) and temperature profiles (30-80 km). From December 1991, lidar observations have been carried out in which the second Stokes line of the stimulated Raman scattering of a KrF laser has been used. Ozone profiles obtained with the NIES lidar system are compared with the data provided by the SAGE II satellite sensor. Results showed good agreement for the individual and the zonal mean profiles. Variations of ozone with various time scales at each altitude can be studied using the data obtained with the NIES ozone lidar system. Seasonal variations are easily found at 20 km, 30 km, and 35 km, which are qualitatively understood as a result of dynamical and photochemical effects. Systematic errors of ozone profiles due to the Pinatubo stratospheric aerosols have been detected using multi-wavelength observation

  14. Variations of surface ozone concentration across the Klang Valley, Malaysia

    Science.gov (United States)

    Latif, Mohd Talib; Huey, Lim Shun; Juneng, Liew

    2012-12-01

    Hourly air quality data covering the period 2004-2008 was obtained from the Air Quality Division, the Department of Environment (DOE) through long-term monitoring by Alam Sekitar Sdn. Bhd. (ASMA) were analysed to investigate the variations of surface ozone (O3) in the Klang Valley, Malaysia. A total of nine monitoring stations were selected for analysis in this study and the results show that there are distinct seasonal patterns in the surface O3 across the Klang Valley. A high surface O3 concentration is usually observed between January and April, while a low surface O3 concentration is found between June and August. Analysis of daily variations in surface O3 and the precursors - NO, NO2, CO, NMHC and UVb, indicate that the surface O3 photochemistry in this study area exhibits a positive response to the intensity and wavelength in UVb while being influenced by the concentration of NOx, particularly through tritration processes. Although results from our study suggested that NMHCs may influence the maximum O3 concentration, further investigation is required. Wind direction during different monsoons was found to influence the concentration of O3 around the Klang Valley. HYSPLIT back trajectories (-72 h) were used to indicate the air-mass transport patterns on days with high concentrations of surface O3 in the study area. Results show that 47% of the high O3 days was associated with the localized circulation. The remaining 32% and 22% were associated with mid-range and long-range transport across the South China Sea from the northeast.

  15. Report on fine particulates and ozone in Quebec in connection with the Canada Wide Standard : 2009 report

    International Nuclear Information System (INIS)

    Busque, D.; Bisson, M.; Paradis, J.; Proulx, M.; Guay, M.

    2010-05-01

    In June 2000, the federal and provincial governments, with the exception of Quebec, adopted a Canada Wide Standard (CWS) for particulates and ozone and set out to reduce these pollutants by 2010. Although Quebec was not a signatory to the CWS, it acts in coherence with the other governments regarding these air quality standards. Ozone and particulates are the main precursors to smog and are known to cause health and environmental problems. Ozone forms when nitrogen oxides and volatile organic compounds (VOCs) chemically react, particularly during hot sunny days. The CWS is a strategy to reduce the risk of these pollutants to public health and the environment. In order to apply this standard, Quebec must verify conformity for regions with a population of more than 100,000, which includes 6 regions, notably Montreal, Quebec City, Gatineau, the Saguenay, Sherbrooke and Trois Rivieres. Results of a 2008 study showed that air quality in Gatineau and 3 subregions of Montreal exceeded the allow limit of 65 ppb for ozone. However, ozone concentrations in Quebec City, the Saguenay, Sherbrooke and Trois Rivieres were under the allowable limits. Results of the 2008 study showed that particulate concentration in all regions were blow the allowable limits. This document revealed that there has been an improvement in air quality in terms of ozone and particulates since 2005. Most regions in Quebec were under the allowable limits projected for 2010. 7 refs., 1 tab., 6 figs., 6 appendices.

  16. The Effects of Acute Dopamine Precursor Depletion on the Cognitive Control Functions of Performance Monitoring and Conflict Processing: An Event-Related Potential (ERP) Study.

    Science.gov (United States)

    Larson, Michael J; Clayson, Peter E; Primosch, Mark; Leyton, Marco; Steffensen, Scott C

    2015-01-01

    Studies using medications and psychiatric populations implicate dopamine in cognitive control and performance monitoring processes. However, side effects associated with medication or studying psychiatric groups may confound the relationship between dopamine and cognitive control. To circumvent such possibilities, we utilized a randomized, double-blind, placebo-controlled, within-subjects design wherein participants were administered a nutritionally-balanced amino acid mixture (BAL) and an amino acid mixture deficient in the dopamine precursors tyrosine (TYR) and phenylalanine (PHE) on two separate occasions. Order of sessions was randomly assigned. Cognitive control and performance monitoring were assessed using response times (RT), error rates, the N450, an event-related potential (ERP) index of conflict monitoring, the conflict slow potential (conflict SP), an ERP index of conflict resolution, and the error-related negativity (ERN) and error positivity (Pe), ERPs associated with performance monitoring. Participants were twelve males who completed a Stroop color-word task while ERPs were collected four hours following acute PHE and TYR depletion (APTD) or balanced (BAL) mixture ingestion in two separate sessions. N450 and conflict SP ERP amplitudes significantly differentiated congruent from incongruent trials, but did not differ as a function of APTD or BAL mixture ingestion. Similarly, ERN and Pe amplitudes showed significant differences between error and correct trials that were not different between APTD and BAL conditions. Findings indicate that acute dopamine precursor depletion does not significantly alter cognitive control and performance monitoring ERPs. Current results do not preclude the role of dopamine in these processes, but suggest that multiple methods for dopamine-related hypothesis testing are needed.

  17. The Effects of Acute Dopamine Precursor Depletion on the Cognitive Control Functions of Performance Monitoring and Conflict Processing: An Event-Related Potential (ERP Study.

    Directory of Open Access Journals (Sweden)

    Michael J Larson

    Full Text Available Studies using medications and psychiatric populations implicate dopamine in cognitive control and performance monitoring processes. However, side effects associated with medication or studying psychiatric groups may confound the relationship between dopamine and cognitive control. To circumvent such possibilities, we utilized a randomized, double-blind, placebo-controlled, within-subjects design wherein participants were administered a nutritionally-balanced amino acid mixture (BAL and an amino acid mixture deficient in the dopamine precursors tyrosine (TYR and phenylalanine (PHE on two separate occasions. Order of sessions was randomly assigned. Cognitive control and performance monitoring were assessed using response times (RT, error rates, the N450, an event-related potential (ERP index of conflict monitoring, the conflict slow potential (conflict SP, an ERP index of conflict resolution, and the error-related negativity (ERN and error positivity (Pe, ERPs associated with performance monitoring. Participants were twelve males who completed a Stroop color-word task while ERPs were collected four hours following acute PHE and TYR depletion (APTD or balanced (BAL mixture ingestion in two separate sessions. N450 and conflict SP ERP amplitudes significantly differentiated congruent from incongruent trials, but did not differ as a function of APTD or BAL mixture ingestion. Similarly, ERN and Pe amplitudes showed significant differences between error and correct trials that were not different between APTD and BAL conditions. Findings indicate that acute dopamine precursor depletion does not significantly alter cognitive control and performance monitoring ERPs. Current results do not preclude the role of dopamine in these processes, but suggest that multiple methods for dopamine-related hypothesis testing are needed.

  18. Ozone modeling

    Energy Technology Data Exchange (ETDEWEB)

    McIllvaine, C M

    1994-07-01

    Exhaust gases from power plants that burn fossil fuels contain concentrations of sulfur dioxide (SO{sub 2}), nitric oxide (NO), particulate matter, hydrocarbon compounds and trace metals. Estimated emissions from the operation of a hypothetical 500 MW coal-fired power plant are given. Ozone is considered a secondary pollutant, since it is not emitted directly into the atmosphere but is formed from other air pollutants, specifically, nitrogen oxides (NO), and non-methane organic compounds (NMOQ) in the presence of sunlight. (NMOC are sometimes referred to as hydrocarbons, HC, or volatile organic compounds, VOC, and they may or may not include methane). Additionally, ozone formation Alternative is a function of the ratio of NMOC concentrations to NO{sub x} concentrations. A typical ozone isopleth is shown, generated with the Empirical Kinetic Modeling Approach (EKMA) option of the Environmental Protection Agency's (EPA) Ozone Isopleth Plotting Mechanism (OZIPM-4) model. Ozone isopleth diagrams, originally generated with smog chamber data, are more commonly generated with photochemical reaction mechanisms and tested against smog chamber data. The shape of the isopleth curves is a function of the region (i.e. background conditions) where ozone concentrations are simulated. The location of an ozone concentration on the isopleth diagram is defined by the ratio of NMOC and NO{sub x} coordinates of the point, known as the NMOC/NO{sub x} ratio. Results obtained by the described model are presented.

  19. Control of aliphatic halogenated DBP precursors with multiple drinking water treatment processes: Formation potential and integrated toxicity.

    Science.gov (United States)

    Zhang, Yimeng; Chu, Wenhai; Yao, Dechang; Yin, Daqiang

    2017-08-01

    The comprehensive control efficiency for the formation potentials (FPs) of a range of regulated and unregulated halogenated disinfection by-products (DBPs) (including carbonaceous DBPs (C-DBPs), nitrogenous DBPs (N-DBPs), and iodinated DBPs (I-DBPs)) with the multiple drinking water treatment processes, including pre-ozonation, conventional treatment (coagulation-sedimentation, pre-sand filtration), ozone-biological activated carbon (O 3 -BAC) advanced treatment, and post-sand filtration, was investigated. The potential toxic risks of DBPs by combing their FPs and toxicity values were also evaluated. The results showed that the multiple drinking water treatment processes had superior performance in removing organic/inorganic precursors and reducing the formation of a range of halogenated DBPs. Therein, ozonation significantly removed bromide and iodide, and thus reduced the formation of brominated and iodinated DBPs. The removal of organic carbon and nitrogen precursors by the conventional treatment processes was substantially improved by O 3 -BAC advanced treatment, and thus prevented the formation of chlorinated C-DBPs and N-DBPs. However, BAC filtration leads to the increased formation of brominated C-DBPs and N-DBPs due to the increase of bromide/DOC and bromide/DON. After the whole multiple treatment processes, the rank order for integrated toxic risk values caused by these halogenated DBPs was haloacetonitriles (HANs)≫haloacetamides (HAMs)>haloacetic acids (HAAs)>trihalomethanes (THMs)>halonitromethanes (HNMs)≫I-DBPs (I-HAMs and I-THMs). I-DBPs failed to cause high integrated toxic risk because of their very low FPs. The significant higher integrated toxic risk value caused by HANs than other halogenated DBPs cannot be ignored. Copyright © 2017. Published by Elsevier B.V.

  20. Health burdens of surface ozone in the UK for a range of future scenarios

    OpenAIRE

    Heal, Mathew R.; Heaviside, Clare; Doherty, Ruth M.; Vieno, Massimo; Stevenson, David S.; Vardoulakis, Sotiris

    2013-01-01

    Exposure to surface ozone (O3), which is influenced by emissions of precursor chemical species, meteorology and population distribution, is associated with excess mortality and respiratory morbidity. In this study, the EMEP-WRF atmospheric chemistry transport model was used to simulate surface O3 concentrations at 5 km horizontal resolution over the British Isles for a baseline year of 2003, for three anthropogenic emissions scenarios for 2030, and for a + 5 °C increase in air temperature on ...

  1. The Antarctic ozone hole

    International Nuclear Information System (INIS)

    Jones, Anna E

    2008-01-01

    Since the mid 1970s, the ozone layer over Antarctica has experienced massive destruction during every spring. In this article, we will consider the atmosphere, and what ozone and the ozone layer actually are. We explore the chemistry responsible for the ozone destruction, and learn about why conditions favour ozone destruction over Antarctica. For the historical perspective, the events leading up to the discovery of the 'hole' are presented, as well as the response from the international community and the measures taken to protect the ozone layer now and into the future

  2. Evidence for a continuous decline in lower stratospheric ozone offsetting ozone layer recovery

    Science.gov (United States)

    Ball, William T.; Alsing, Justin; Mortlock, Daniel J.; Staehelin, Johannes; Haigh, Joanna D.; Peter, Thomas; Tummon, Fiona; Stübi, Rene; Stenke, Andrea; Anderson, John; Bourassa, Adam; Davis, Sean M.; Degenstein, Doug; Frith, Stacey; Froidevaux, Lucien; Roth, Chris; Sofieva, Viktoria; Wang, Ray; Wild, Jeannette; Yu, Pengfei; Ziemke, Jerald R.; Rozanov, Eugene V.

    2018-02-01

    Ozone forms in the Earth's atmosphere from the photodissociation of molecular oxygen, primarily in the tropical stratosphere. It is then transported to the extratropics by the Brewer-Dobson circulation (BDC), forming a protective ozone layer around the globe. Human emissions of halogen-containing ozone-depleting substances (hODSs) led to a decline in stratospheric ozone until they were banned by the Montreal Protocol, and since 1998 ozone in the upper stratosphere is rising again, likely the recovery from halogen-induced losses. Total column measurements of ozone between the Earth's surface and the top of the atmosphere indicate that the ozone layer has stopped declining across the globe, but no clear increase has been observed at latitudes between 60° S and 60° N outside the polar regions (60-90°). Here we report evidence from multiple satellite measurements that ozone in the lower stratosphere between 60° S and 60° N has indeed continued to decline since 1998. We find that, even though upper stratospheric ozone is recovering, the continuing downward trend in the lower stratosphere prevails, resulting in a downward trend in stratospheric column ozone between 60° S and 60° N. We find that total column ozone between 60° S and 60° N appears not to have decreased only because of increases in tropospheric column ozone that compensate for the stratospheric decreases. The reasons for the continued reduction of lower stratospheric ozone are not clear; models do not reproduce these trends, and thus the causes now urgently need to be established.

  3. Evidence for a Continuous Decline in Lower Stratospheric Ozone Offsetting Ozone Layer Recovery

    Science.gov (United States)

    Ball, William T.; Alsing, Justin; Mortlock, Daniel J.; Staehelin, Johannes; Haigh, Joanna D.; Peter, Thomas; Tummon, Fiona; Stuebi, Rene; Stenke, Andrea; Anderson, John; hide

    2018-01-01

    Ozone forms in the Earth's atmosphere from the photodissociation of molecular oxygen, primarily in the tropical stratosphere. It is then transported to the extratropics by the Brewer-Dobson circulation (BDC), forming a protective "ozone layer" around the globe. Human emissions of halogen-containing ozone-depleting substances (hODSs) led to a decline in stratospheric ozone until they were banned by the Montreal Protocol, and since 1998 ozone in the upper stratosphere is rising again, likely the recovery from halogen-induced losses. Total column measurements of ozone between the Earth's surface and the top of the atmosphere indicate that the ozone layer has stopped declining across the globe, but no clear increase has been observed at latitudes between 60degS and 60degN outside the polar regions (60-90deg). Here we report evidence from multiple satellite measurements that ozone in the lower stratosphere between 60degS and 60degN has indeed continued to decline since 1998. We find that, even though upper stratospheric ozone is recovering, the continuing downward trend in the lower stratosphere prevails, resulting in a downward trend in stratospheric column ozone between 60degS and 60degN. We find that total column ozone between 60degS and 60degN appears not to have decreased only because of increases in tropospheric column ozone that compensate for the stratospheric decreases. The reasons for the continued reduction of lower stratospheric ozone are not clear; models do not reproduce these trends, and thus the causes now urgently need to be established.

  4. Ozonated Olive Oils and Troubles

    Directory of Open Access Journals (Sweden)

    Bulent Uysal

    2014-04-01

    Full Text Available One of the commonly used methods for ozone therapy is ozonated oils. Most prominent type of used oils is extra virgin olive oil. But still, each type of unsaturated oils may be used for ozonation. There are a lot of wrong knowledge on the internet about ozonated oils and its use as well. Just like other ozone therapy studies, also the studies about ozone oils are inadequate to avoid incorrect knowledge. Current data about ozone oil and its benefits are produced by supplier who oversees financial interests and make misinformation. Despite the rapidly increasing ozone oil sales through the internet, its quality and efficacy is still controversial. Dozens of companies and web sites may be easily found to buy ozonated oil. But, very few of these products are reliable, and contain sufficiently ozonated oil. This article aimed to introduce the troubles about ozonated oils and so to inform ozonated oil users. [J Intercult Ethnopharmacol 2014; 3(2.000: 49-50

  5. Variations of Ground-level Ozone Concentration in Malaysia: A Case Study in West Coast of Peninsular Malaysia

    Directory of Open Access Journals (Sweden)

    Hashim Nur Izzah Mohamad

    2017-01-01

    Full Text Available Hourly ground ozone concentration, measured from the monitoring stations in the West Coast of Peninsular Malaysia for the period of 10 years (2003-2012 were used to analyse the ozone characteristic in Nilai, Melaka and Petaling Jaya. The prediction of tropospheric ozone concentrations is very important due to the negative impacts of ozone on human health, climate and vegetation. The mean concentration of ozone at the studied areas had not exceeded the recommended value of Malaysia Ambient Air Quality Guideline (MAAQG for 8-hour average (0.06 ppm, however some of the measurements exceeded the hourly permitted concentration by MAAQG that is 0.1 ppm. Higher concentration of ozone can be observed during the daytime since ozone needs sunlight for the photochemical reactions. The diurnal cycle of ozone concentration has a mid-day peak (14:00-15:00 and lower night-time concentrations. The ozone concentration slowly rises after the sun rises (08:00, reaching a maximum during daytime and then decreases until the next morning.

  6. An Atlantic streamer in stratospheric ozone observations and SD-WACCM simulation data

    Science.gov (United States)

    Hocke, Klemens; Schranz, Franziska; Maillard Barras, Eliane; Moreira, Lorena; Kämpfer, Niklaus

    2017-03-01

    Observation and simulation of individual ozone streamers are important for the description and understanding of non-linear transport processes in the middle atmosphere. A sudden increase in mid-stratospheric ozone occurred above central Europe on 4 December 2015. The GROund-based Millimeter-wave Ozone Spectrometer (GROMOS) and the Stratospheric Ozone MOnitoring RAdiometer (SOMORA) in Switzerland measured an ozone enhancement of about 30 % at 34 km altitude (8.3 hPa) from 1 to 4 December. A similar ozone increase is simulated by the Specified Dynamics Whole Atmosphere Community Climate (SD-WACCM) model. Further, the global ozone fields at 34 km altitude (8.3 hPa) from SD-WACCM and the satellite experiment Aura/MLS show a remarkable agreement for the location and timing of an ozone streamer (large-scale tongue-like structure) extending from the subtropics in northern America over the Atlantic to central Europe. This agreement indicates that SD-WACCM can inform us about the wind inside the Atlantic ozone streamer. SD-WACCM shows an eastward wind of about 100 m s-1 inside the Atlantic streamer in the mid-stratosphere. SD-WACCM shows that the Atlantic streamer flows along the edge of the polar vortex. The Atlantic streamer turns southward at an erosion region of the polar vortex located above the Caspian Sea. The spatial distribution of stratospheric water vapour indicates a filament outgoing from this erosion region. The Atlantic streamer, the polar vortex erosion region and the water vapour filament belong to the process of planetary wave breaking in the so-called surf zone of the northern midlatitude winter stratosphere.

  7. The Effect of Representing Bromine from VSLS on the Simulation and Evolution of Antarctic Ozone

    Science.gov (United States)

    Oman, Luke D.; Douglass, Anne R.; Salawitch, Ross J.; Canty, Timothy P.; Ziemke, Jerald R.; Manyin, Michael

    2016-01-01

    We use the Goddard Earth Observing System Chemistry Climate Model (GEOSCCM), a contributor to both the 2010 and 2014 WMO Ozone Assessment Reports, to show that inclusion of 5 parts per trillion (ppt) of stratospheric bromine(Br(sub y)) from very short lived substances (VSLS) is responsible for about a decade delay in ozone hole recovery. These results partially explain the significantly later recovery of Antarctic ozone noted in the 2014 report, as bromine from VSLS was not included in the 2010 Assessment. We show multiple lines of evidence that simulations that account for VSLS Br(sub y) are in better agreement with both total column BrO and the seasonal evolution of Antarctic ozone reported by the Ozone Monitoring Instrument (OMI) on NASAs Aura satellite. In addition, the near zero ozone levels observed in the deep Antarctic lower stratospheric polar vortex are only reproduced in a simulation that includes this Br(sub y) source from VSLS.

  8. On-line monitoring of ozonation through estimation of Ct value and AOC formation with UV/Vis spectrometry

    NARCIS (Netherlands)

    Ross, P.S.; Van der Helm, A.W.C.; Van den Broeke, J.; Rietveld, L.C.

    2012-01-01

    The application of ozone in water treatment serves many purposes, such as disinfection, degradation of organic micro-pollutants and oxidation of taste, odour and colour producing compounds. A commonly used method to determine the disinfection capacity of ozonation is calculating the exposure of

  9. The total ozone and UV solar radiation over Stara Zagora, Bulgaria

    Science.gov (United States)

    Mendeva, B. D.; Gogosheva, Ts. N.; Petkov, B. H.; Krastev, D. G.

    The results from direct ground-based solar UV irradiance measurements and the total ozone content (TOC) over Stara Zagora (42° 25'N, 25° 37'E), Bulgaria are presented. During the period 1999-2003 the TOC data show seasonal variations, typical for the middle latitudes - maximum in the spring and minimum in the autumn. The comparison between TOC ground-based data and Global Ozone Monitoring Experiment (GOME) satellite-borne ones shows a seasonal dependence of the differences between them. A strong negative relationship between the total ozone and the 305 nm wavelength irradiance was found. The dependence between the two variables is significant ( r = -0.62 ± 0.18) at 98% confidence level. The direct sun UV doses for some specific biological effects (erythema and eyes) are obtained. The estimation of the radiation amplification factor RAF shows that the ozone reduction by 1% increases the erythemal dose by 2.3%. The eye-damaging doses are more influenced by the TOC changes and in this case RAF = -2.7%. The amount of these biological doses depended on the solar altitude over the horizon. This dependence was not so strong when the total ozone content in the atmosphere was lower.

  10. SMM mesospheric ozone measurements

    Science.gov (United States)

    Aikin, A. C.

    1990-01-01

    The main objective was to understand the secular and seasonal behavior of ozone in the lower mesosphere, 50 to 70 km. This altitude region is important in understanding the factors which determine ozone behavior. A secondary objective is the study of stratospheric ozone in the polar regions. Use is made of results from the SBUV satellite borne instrument. In the Arctic the interaction between chlorine compounds and low molecular weight hydrocarbons is studied. More than 30,000 profiles were obtained using the UVSP instrument on the SMM spacecraft. Several orbits of ozone data per day were obtained allowing study of the current rise in solar activity from the minimum until the present. Analysis of Nimbus 7 SBUV data in Antarctic spring indicates that ozone is depleted within the polar vortex relative to ozone outside the vortex. This depletion confirms the picture of ozone loss at altitudes where polar stratospheric clouds exist. In addition, there is ozone loss above the cloud level indicating that there is another mechanism in addition to ozone loss initiated by heterogeneous chlorine reactions on cloud particles.

  11. Tropospheric and total ozone columns over Paris (France measured using medium-resolution ground-based solar-absorption Fourier-transform infrared spectroscopy

    Directory of Open Access Journals (Sweden)

    C. Viatte

    2011-10-01

    Full Text Available Ground-based Fourier-transform infrared (FTIR solar absorption spectroscopy is a powerful remote sensing technique providing information on the vertical distribution of various atmospheric constituents. This work presents the first evaluation of a mid-resolution ground-based FTIR to measure tropospheric ozone, independently of stratospheric ozone. This is demonstrated using a new atmospheric observatory (named OASIS for "Observations of the Atmosphere by Solar absorption Infrared Spectroscopy", installed in Créteil (France. The capacity of the technique to separate stratospheric and tropospheric ozone is demonstrated. Daily mean tropospheric ozone columns derived from the Infrared Atmospheric Sounding Interferometer (IASI and from OASIS measurements are compared for summer 2009 and a good agreement of −5.6 (±16.1 % is observed. Also, a qualitative comparison between in-situ surface ozone measurements and OASIS data reveals OASIS's capacity to monitor seasonal tropospheric ozone variations, as well as ozone pollution episodes in summer 2009 around Paris. Two extreme pollution events are identified (on the 1 July and 6 August 2009 for which ozone partial columns from OASIS and predictions from a regional air-quality model (CHIMERE are compared following strict criteria of temporal and spatial coincidence. An average bias of 0.2%, a mean square error deviation of 7.6%, and a correlation coefficient of 0.91 is found between CHIMERE and OASIS, demonstrating the potential of a mid-resolution FTIR instrument in ground-based solar absorption geometry for tropospheric ozone monitoring.

  12. An upper tropospheric ‘ozone river’ from Africa to India during the 2008 Asian post-monsoon season

    Directory of Open Access Journals (Sweden)

    Flore Tocquer

    2015-03-01

    Full Text Available We have used ozone data from the Infrared Atmospheric Sounding Interferometer to follow an event of ozone-enriched air-masses in the upper troposphere from eastern Africa to northern India. The ozone transport (hereafter called ‘ozone river’ or O3R occurred during the Asian post-monsoon season in 2008 and was associated with Rossby wave propagation. The persistence of the O3R in a narrow channel was confirmed by MOZAIC airborne data over the northwestern Indian coast. The regions of origin of the O3R were identified by a transport analysis based on the Lagrangian model FLEXPART. The Lagrangian simulations combined with potential vorticity fields indicate that stratospheric intrusions are not likely to be the most important contributor to the observed O3 enhancements. A high-resolution Eulerian model, Meso-NH, with tagged tracers was used to discriminate between African biomass burning, lightnings and Indian anthropogenic pollution as potential sources of precursors for the O3R. Lightning NOx emissions, associated with convective clouds over Africa, were found to be the principal contributor to the ozone enhancement over the Indian Ocean taking advantage of a northeastward jet. This case study illustrates African lightning emissions as an important source for enhanced O3 in the upper troposphere over the Indian Ocean region during the post-monsoon season.

  13. Impact of forest fires, biogenic emissions and high temperatures on the elevated Eastern Mediterranean ozone levels during the hot summer of 2007

    NARCIS (Netherlands)

    Hodnebrog, Ø.; Solberg, S.; Stordal, F.; Svendby, T.M.; Simpson, D.; Gauss, M.; Hilboll, A.; Pfister, G.G.; Turquety, S.; Richter, A.; Burrows, J.P.; Denier Van Der Gon, H.A.C.

    2012-01-01

    The hot summer of 2007 in southeast Europe has been studied using two regional atmospheric chemistry models; WRF-Chem and EMEP MSC-W. The region was struck by three heat waves and a number of forest fire episodes, greatly affecting air pollution levels. We have focused on ozone and its precursors

  14. Reações de ozonólise de olefinas em fase gasosa

    Directory of Open Access Journals (Sweden)

    Nunes Fabíola Maria Nobre

    2000-01-01

    Full Text Available Biogenic emissions of volatile organic compounds play a fundamental role in the atmospheric chemistry, vegetation being one of their major sources. Amongst the VOCs emitted by plants, olefins and terpenoids are the most abundant. These compounds, due to the presence of two or more double bonds and other structural features, are very reactive in the atmosphere and act as precursors of the photochemical smog and aerosols. This article presents a review of the reactions of olefins and terpenoids with ozone, in the gas phase, with emphasis toward the mechanisms and kinetic aspects.

  15. Detectability of the impacts of ozone-depleting substances and greenhouse gases upon stratospheric ozone accounting for nonlinearities in historical forcings

    Science.gov (United States)

    Bandoro, Justin; Solomon, Susan; Santer, Benjamin D.; Kinnison, Douglas E.; Mills, Michael J.

    2018-01-01

    the upper- or lower-stratospheric SWOOSH data, irrespective of the signal detection method used. In the WACCM simulations of future climate change, the GHG signal is statistically identifiable between 2020 and 2030. Our findings demonstrate the importance of continued stratospheric ozone monitoring to improve estimates of the contributions of ODS and GHG forcing to global changes in stratospheric ozone.

  16. Seasonal and species-specific response of VOC emissions by Mediterranean woody plant to elevated ozone concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Llusia, J.; Penuelas, J. [Universitat Autonoma de Barcelona (Spain). Unitat Ecofisiologia CSIC-CEAB-CREAF; Gimeno, R.S. [CIEMAT, Madrid (Spain). Ecotoxicologia de la Contaminacion Atmosferica

    2002-08-01

    %) and total VOC (45%) emission rates in ozone-fumigated plants, whereas stomatal conductance did not change. Since VOCs are precursors of ozone, the increase in BVOC emission as a consequence of elevated tropospheric ozone concentrations may lead to positive feedback mechanisms in ozone formation. (author)

  17. Seasonal and species-specific response of VOC emissions by Mediterranean woody plant to elevated ozone concentrations

    Science.gov (United States)

    Llusià, J.; Peñuelas, J.; Gimeno, B. S.

    %) emission rates in ozone-fumigated plants, whereas stomatal conductance did not change. Since VOCs are precursors of ozone, the increase in BVOC emission as a consequence of elevated tropospheric ozone concentrations may lead to positive feedback mechanisms in ozone formation.

  18. Formation, precursors, control, and occurrence of nitrosamines in drinking water: a review.

    Science.gov (United States)

    Krasner, Stuart W; Mitch, William A; McCurry, Daniel L; Hanigan, David; Westerhoff, Paul

    2013-09-01

    This review summarizes major findings over the last decade related to nitrosamines in drinking water, with a particular focus on N-nitrosodimethylamine (NDMA), because it is among the most widely detected nitrosamines in drinking waters. The reaction of inorganic dichloramine with amine precursors is likely the dominant mechanism responsible for NDMA formation in drinking waters. Even when occurrence surveys found NDMA formation in chlorinated drinking waters, it is unclear whether chloramination resulted from ammonia in the source waters. NDMA formation has been associated with the use of quaternary amine-based coagulants and anion exchange resins, and wastewater-impaired source waters. Specific NDMA precursors in wastewater-impacted source waters may include tertiary amine-containing pharmaceuticals or other quaternary amine-containing constituents of personal care products. Options for nitrosamine control include physical removal of precursors by activated carbon or precursor deactivation by application of oxidants, particularly ozone or chlorine, upstream of chloramination. Although NDMA has been the most prevalent nitrosamine detected in worldwide occurrence surveys, it may account for only ≈ 5% of all nitrosamines in chloraminated drinking waters. Other significant contributors to total nitrosamines are poorly characterized. However, high levels of certain low molecular weight nitrosamines have been detected in certain Chinese waters suspected to be impaired by industrial effluents. The review concludes by identifying research needs that should be addressed over the next decade. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Ozone Antimicrobial Efficacy

    Science.gov (United States)

    Ozone is a potent germicide that has been used extensively for water purification. In Europe, 90 percent of the municipal water systems are treated with ozone, and in France, ozone has been used to treat drinking water since 1903. However, there is limited information on the bioc...

  20. A Global Climatology of Tropospheric and Stratospheric Ozone Derived from Aura OMI and MLS Measurements

    Science.gov (United States)

    Ziemke, J.R.; Chandra, S.; Labow, G.; Bhartia, P. K.; Froidevaux, L.; Witte, J. C.

    2011-01-01

    A global climatology of tropospheric and stratospheric column ozone is derived by combining six years of Aura Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) ozone measurements for the period October 2004 through December 2010. The OMI/MLS tropospheric ozone climatology exhibits large temporal and spatial variability which includes ozone accumulation zones in the tropical south Atlantic year-round and in the subtropical Mediterranean! Asia region in summer months. High levels of tropospheric ozone in the northern hemisphere also persist in mid-latitudes over the eastern North American and Asian continents extending eastward over the Pacific Ocean. For stratospheric ozone climatology from MLS, largest ozone abundance lies in the northern hemisphere in the latitude range 70degN-80degN in February-April and in the southern hemisphere around 40degS-50degS during months August-October. The largest stratospheric ozone abundances in the northern hemisphere lie over North America and eastern Asia extending eastward across the Pacific Ocean and in the southern hemisphere south of Australia extending eastward across the dateline. With the advent of many newly developing 3D chemistry and transport models it is advantageous to have such a dataset for evaluating the performance of the models in relation to dynamical and photochemical processes controlling the ozone distributions in the troposphere and stratosphere.

  1. Effects of ozone on the various digital print technologies: Photographs and documents

    Energy Technology Data Exchange (ETDEWEB)

    Burge, D; Gordeladze, N; Bigourdan, J-L; Nishimura, D, E-mail: dmbpph@rit.ed [Image Permanence Institute at Rochester Institute of Technology, 70 Lomb Memorial Drive, Rochester, NY 14623 (United States)

    2010-06-01

    The harmful effects of ozone on inkjet photographs have been well documented. This project expands on that research by performing ozone tests on a greater variety of digital prints including colour electrophotographic and dye sublimation. The sensitivities of these materials are compared to traditionally printed materials (black-and-white electrophotographic, colour photographic and offset lithographic) to determine if the digital prints require special care practices. In general, the digital prints were more sensitive to ozone than traditional prints. Dye inkjet prints were more sensitive to fade than pigment inkjet, though pigment was not immune. The dye sublimation, colour electrophotographic (dry and liquid toner), and traditional print systems were relatively resistant to ozone. Text-based documents were evaluated in addition to photographic images, since little work has been done to determine if the type of object (image or text) has an impact on its sensitivity to ozone. The results showed that documents can be more resistant to ozone than photographs even when created using the same printer and inks. It is recommended that cultural heritage institutions not expose their porous-coated, dye-based inkjet photos to open air for extended periods of time. Other inkjet prints should be monitored for early signs of change.

  2. Effects of ozone on the various digital print technologies: Photographs and documents

    International Nuclear Information System (INIS)

    Burge, D; Gordeladze, N; Bigourdan, J-L; Nishimura, D

    2010-01-01

    The harmful effects of ozone on inkjet photographs have been well documented. This project expands on that research by performing ozone tests on a greater variety of digital prints including colour electrophotographic and dye sublimation. The sensitivities of these materials are compared to traditionally printed materials (black-and-white electrophotographic, colour photographic and offset lithographic) to determine if the digital prints require special care practices. In general, the digital prints were more sensitive to ozone than traditional prints. Dye inkjet prints were more sensitive to fade than pigment inkjet, though pigment was not immune. The dye sublimation, colour electrophotographic (dry and liquid toner), and traditional print systems were relatively resistant to ozone. Text-based documents were evaluated in addition to photographic images, since little work has been done to determine if the type of object (image or text) has an impact on its sensitivity to ozone. The results showed that documents can be more resistant to ozone than photographs even when created using the same printer and inks. It is recommended that cultural heritage institutions not expose their porous-coated, dye-based inkjet photos to open air for extended periods of time. Other inkjet prints should be monitored for early signs of change.

  3. Long-term Measurements of Summer-time Ozone at the Walnut Grove Tower - Understanding Trends in the Boundary Layer

    Science.gov (United States)

    Mahmud, A.; Di, P.; Mims, D.; Avise, J.; DaMassa, J.; Kaduwela, A. P.

    2015-12-01

    The California Air Resources Board (CARB) has been monitoring boundary layer ozone at the Walnut Grove Tower (WGT) since 1996 for investigating regional transport and vertical profile. Walnut Grove is located between Sacramento and Stockton, CA in the Sacramento - San Joaquin Delta. Sampling inlets are positioned at 30-ft, 400-ft, 800-ft, 1200-ft and 1600-ft levels of the 2000-ft tower, which is one of the tallest monitoring towers in the Western US. Ozone, ambient temperature, wind speed, and wind direction are simultaneously measured at each level, and reported as hourly averages. The current study included analyses of available ozone and corresponding meteorological data for the months of June - September from 1996 - 2014 with objectives to: 1) explore trends and inter-annual variability of ozone, 2) examine any correlations between ozone and meteorological parameters, 3) understand interactions of ozone measured at various levels, and 4) assess how well a regulatory state-of-the-science air quality model such as the Community Multi-scale Air Quality Model (CMAQ) captures observation. Daily 1-hr maximum ozone has been consistently decreasing during the 1996 - 2014 period at a rate of ~1 ppb per year. This indicates that CARB's measures to control ambient ozone have been effective over the past years. Evolution of the vertical profile throughout the day shows that ozone is fairly homogeneously mixed between 1 - 5 pm, when mixing height typically reaches the maximum. Ozone at 30-ft shows the greatest variability because of its proximity to the ground and emissions sources - rises faster during morning hours (7 - 10 am) and declines more rapidly during evening hours (7 - 10 pm) compared to other levels. Air masses reaching the tower are predominantly southwesterly (247 - 257 deg.) at the bottom, and southwesterly to slightly northwesterly (254 - 302 deg.) at top levels. Daily 1-hr maximum ozone was negatively correlated with wind speed (i.e. ozone was high under

  4. Assessment and Applications of NASA Ozone Data Products Derived from Aura OMI-MLS Satellite Measurements in Context of the GMI Chemical Transport Model

    Science.gov (United States)

    Ziemke, J. R.; Olsen, M. A.; Witte, J. C.; Douglass, A. R.; Strahan, S. E.; Wargan, K.; Liu, X.; Schoeberl, M. R.; Yang, K.; Kaplan, T. B.; hide

    2013-01-01

    Measurements from the Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS), both onboard the Aura spacecraft, have been used to produce daily global maps of column and profile ozone since August 2004. Here we compare and evaluate three strategies to obtain daily maps of tropospheric and stratospheric ozone from OMI and MLS measurements: trajectory mapping, direct profile retrieval, and data assimilation. Evaluation is based upon an assessment that includes validation using ozonesondes and comparisons with the Global Modeling Initiative (GMI) chemical transport model (CTM). We investigate applications of the three ozone data products from near-decadal and inter-annual timescales to day-to-day case studies. Zonally averaged inter-annual changes in tropospheric ozone from all of the products in any latitude range are of the order 1-2 Dobson Units while changes (increases) over the 8-year Aura record investigated http://eospso.gsfc.nasa.gov/atbd-category/49 vary approximately 2-4 Dobson Units. It is demonstrated that all of the ozone products can measure and monitor exceptional tropospheric ozone events including major forest fire and pollution transport events. Stratospheric ozone during the Aura record has several anomalous inter-annual events including stratospheric warming split events in the Northern Hemisphere extra-tropics that are well captured using the data assimilation ozone profile product. Data assimilation with continuous daily global coverage and vertical ozone profile information is the best of the three strategies at generating a global tropospheric and stratospheric ozone product for science applications.

  5. Impact of Future Emissions and Climate Change on Surface Ozone over China

    Science.gov (United States)

    Ma, C. T.; Westervelt, D. M.; Fiore, A. M.; Rieder, H. E.; Kinney, P.; Wang, S.; Correa, G. J. P.

    2017-12-01

    China's immense ambient air pollution problem and world-leading greenhouse gas emissions place it at the forefront of global efforts to address these related environmental concerns. Here, we analyze the impact of ECLIPSE (Evaluating the Climate and Air Quality Impacts of Short-Lived Pollutants) future emissions scenarios representative of current legislation (CLE) and maximum technically feasible emissions reductions (MFR) on surface ozone (O3) concentrations over China in the 2030s and 2050s, in the context of a changing climate. We use a suite of simulations performed with the NOAA Geophysical Fluid Dynamics Laboratory's AM3 global chemistry-climate model. To estimate the impact of climate change in isolation on Chinese air quality, we hold emissions of air pollutants including O3 precursors fixed at 2015 levels but allow climate (global sea surface temperatures and sea ice cover) to change according to decadal averages for the years 2026-2035 and 2046-2055 from a three-member ensemble of GFDL-CM3 simulations under the RCP8.5 high warming scenario. Evaluation of the present-day simulation (2015 CLE) with observations from 1497 chiefly urban air quality monitoring stations shows that simulated surface O3 is positively biased by 26 ppb on average over the domain of China. Previous studies, however, have shown that the modeled ozone response to changes in NOx emissions over the Eastern United States mirrors the magnitude and structure of observed changes in maximum daily average 8-hour (MDA8) O3 distributions. Therefore, we use the model's simulated changes for the 2030s and 2050s to project changes in policy-relevant MDA8 O3 concentrations. We find an overall increase in MDA8 O3 for CLE scenarios in which emissions of NOx precursors are projected to increase, and under MFR scenarios, an overall decrease, with the highest changes occurring in summertime for both 2030 and 2050 MFR. Under climate change alone, the model simulates a mean summertime decrease of 1.3 ppb

  6. Transport aloft drives peak ozone in the Mojave Desert

    Science.gov (United States)

    VanCuren, Richard

    2015-05-01

    Transport of anthropogenic pollution eastward out of the Los Angeles megacity region in California has been periodically observed to reach the Colorado River and the Colorado Plateau region beyond. In the 1980s, anthropogenic halocarbon tracers measured in and near the Las Angeles urban area and at a mountain-top site near the Colorado River, 400 km downwind, were shown to have a correlated seven-day cycle explainable by transport from the urban area with a time lag of 1-2 days. Recent short term springtime intensive studies using aircraft observations and regional modeling of long range transport of ozone from the Southern California megacity region showed frequent and persistent ozone impacts at surface sites across the Colorado Plateau and Southern Rocky Mountain region, at distances up to 1500 km, also with time lags of 1-2 days. However, the timing of ozone peaks at low altitude monitoring sites within the Mojave Desert, at distances from 100 to 400 km from the South Coast and San Joaquin Valley ozone source regions, does not show the expected time-lag behavior seen in the larger transport studies. This discrepancy is explained by recognizing ozone transport across the Mojave Desert to occur in a persistent layer of polluted air in the lower free troposphere with a base level at approximately 1 km MSL. This layer impacts elevated downwind sites directly, but only influences low altitude surface ozone maxima through deep afternoon mixing. Pollutants in this elevated layer derive from California source regions (the Los Angeles megacity region and the intensive agricultural region of the San Joaquin Valley), from long-range transport from Asia, and stratospheric down-mixing. Recognition of the role of afternoon mixing during spring and summer over the Mojave explains and expands the significance of previously published reports of ozone and other pollutants observed in and over the Mojave Desert, and resolves an apparent paradox in the timing of ozone peaks due to

  7. Laboratory measurement of secondary pollutant yields from ozone reaction with HVAC filters

    International Nuclear Information System (INIS)

    Destaillats, Hugo; Chen, Wenhao; Apte, Michael; Li, Nuan; Spears, Michael; Almosni, Jeremie; Zhang, Jianshun Jensen; Fisk, William J.

    2009-01-01

    We used Proton Transfer Reaction - Mass Spectrometry (PTR-MS) and conventional sampling methods to monitor and identify trace level organic pollutants formed in heterogeneous reactions between ozone and HVAC filters in real time. Experiments were carried out using a bench-scale flow tube reactor operating with dry air and humidified air (50% RH), at realistically high ozone concentrations (150 ppbv). We explored different filter media (i.e., fiberglass and cotton/polyester blends) and different particle loadings (i.e., clean filter and filters loaded with particles for 3 months at the Lawrence Berkeley National Laboratory and the Port of Oakland, CA). Detailed emission dynamics of very low levels of certain organic pollutants from filter media upon ozone exposure in the presence of moisture have been obtained and analyzed.

  8. Ozone exposure and pulmonary effects in panel and human clinical studies: Considerations for design and interpretation.

    Science.gov (United States)

    Rohr, Annette C

    2018-04-01

    A wealth of literature exists regarding the pulmonary effects of ozone, a photochemical pollutant produced by the reaction of nitrogen oxide and volatile organic precursors in the presence of sunlight. This paper focuses on epidemiological panel studies and human clinical studies of ozone exposure, and discusses issues specific to this pollutant that may influence study design and interpretation as well as other, broader considerations relevant to ozone-health research. The issues are discussed using examples drawn from the wider literature. The recent panel and clinical literature is also reviewed. Health outcomes considered include lung function, symptoms, and pulmonary inflammation. Issues discussed include adversity, reversibility, adaptation, variability in ozone exposure metric used and health outcomes evaluated, co-pollutants in panel studies, influence of temperature in panel studies, and multiple comparisons. Improvements in and standardization of panel study approaches are recommended to facilitate comparisons between studies as well as meta-analyses. Additional clinical studies at or near the current National Ambient Air Quality Standard (NAAQS) of 70 ppb are recommended, as are clinical studies in sensitive subpopulations such as asthmatics. The pulmonary health impacts of ozone exposure have been well documented using both epidemiological and chamber study designs. However, there are a number of specific methodological and related issues that should be considered when interpreting the results of these studies and planning additional research, including the standardization of exposure and health metrics to facilitate comparisons among studies.

  9. Multi-model assessment of stratospheric ozone return dates and ozone recovery in CCMVal-2 models

    Directory of Open Access Journals (Sweden)

    V. Eyring

    2010-10-01

    Full Text Available Projections of stratospheric ozone from a suite of chemistry-climate models (CCMs have been analyzed. In addition to a reference simulation where anthropogenic halogenated ozone depleting substances (ODSs and greenhouse gases (GHGs vary with time, sensitivity simulations with either ODS or GHG concentrations fixed at 1960 levels were performed to disaggregate the drivers of projected ozone changes. These simulations were also used to assess the two distinct milestones of ozone returning to historical values (ozone return dates and ozone no longer being influenced by ODSs (full ozone recovery. The date of ozone returning to historical values does not indicate complete recovery from ODSs in most cases, because GHG-induced changes accelerate or decelerate ozone changes in many regions. In the upper stratosphere where CO2-induced stratospheric cooling increases ozone, full ozone recovery is projected to not likely have occurred by 2100 even though ozone returns to its 1980 or even 1960 levels well before (~2025 and 2040, respectively. In contrast, in the tropical lower stratosphere ozone decreases continuously from 1960 to 2100 due to projected increases in tropical upwelling, while by around 2040 it is already very likely that full recovery from the effects of ODSs has occurred, although ODS concentrations are still elevated by this date. In the midlatitude lower stratosphere the evolution differs from that in the tropics, and rather than a steady decrease in ozone, first a decrease in ozone is simulated from 1960 to 2000, which is then followed by a steady increase through the 21st century. Ozone in the midlatitude lower stratosphere returns to 1980 levels by ~2045 in the Northern Hemisphere (NH and by ~2055 in the Southern Hemisphere (SH, and full ozone recovery is likely reached by 2100 in both hemispheres. Overall, in all regions except the tropical lower stratosphere, full ozone recovery from ODSs occurs significantly later than the

  10. Lower tropospheric ozone over India and its linkage to the South Asian monsoon

    Science.gov (United States)

    Lu, Xiao; Zhang, Lin; Liu, Xiong; Gao, Meng; Zhao, Yuanhong; Shao, Jingyuan

    2018-03-01

    Lower tropospheric (surface to 600 hPa) ozone over India poses serious risks to both human health and crops, and potentially affects global ozone distribution through frequent deep convection in tropical regions. Our current understanding of the processes controlling seasonal and long-term variations in lower tropospheric ozone over this region is rather limited due to spatially and temporally sparse observations. Here we present an integrated process analysis of the seasonal cycle, interannual variability, and long-term trends of lower tropospheric ozone over India and its linkage to the South Asian monsoon using the Ozone Monitoring Instrument (OMI) satellite observations for years 2006-2014 interpreted with a global chemical transport model (GEOS-Chem) simulation for 1990-2010. OMI observed lower tropospheric ozone over India averaged for 2006-2010, showing the highest concentrations (54.1 ppbv) in the pre-summer monsoon season (May) and the lowest concentrations (40.5 ppbv) in the summer monsoon season (August). Process analyses in GEOS-Chem show that hot and dry meteorological conditions and active biomass burning together contribute to 5.8 Tg more ozone being produced in the lower troposphere in India in May than January. The onset of the summer monsoon brings ozone-unfavorable meteorological conditions and strong upward transport, which all lead to large decreases in the lower tropospheric ozone burden. Interannually, we find that both OMI and GEOS-Chem indicate strong positive correlations (r = 0.55-0.58) between ozone and surface temperature in pre-summer monsoon seasons, with larger correlations found in high NOx emission regions reflecting NOx-limited production conditions. Summer monsoon seasonal mean ozone levels are strongly controlled by monsoon strengths. Lower ozone concentrations are found in stronger monsoon seasons mainly due to less ozone net chemical production. Furthermore, model simulations over 1990-2010 estimate a mean annual trend of 0

  11. Process Analysis of Typhoon Related Ozone Pollution over the Pearl River Delta during the PRIDE-PRD2006

    Science.gov (United States)

    Li, Y.; Wang, X.; Zhang, Y.

    2014-12-01

    There were two typhoon processes during Campaign PRIDE-PRD2006 in July 2006 and serious ozone pollution episodes occurred before the landing of the typhoons. Chemical transport model CMAQ was employed in this work to simulate the ozone pollution episode related by the typhoon KAEMI. According to the meteorological conditions, the pollution episode could be divided into three phases with the movement of the typhoon, which were (1) far away from the continent; (2) coming close to the continent; (3) before landing. Process analysis was applied to get the contributions of physical and chemical processes for the ozone. It revealed that transport process was dominant during this pollution episode, and the influence of chemical process increased in the second phase. Three typical regions, northern rural area, urban area and Hong Kong area, were selected to study the contribution of each chemical and physical process. In the first phase, the primary process in northern rural area and the urban area was vertical diffusion, accounting for 47% and 46% respectively. In the second phase, the primary process in northern rural area and the urban area was chemical process, accounting for 33% and 31% respectively. In the third phase, the region of high concentration ozone moved southward. For Hong Kong area, the western inflow was prominent as 40%. Sensitivity study showed that urban areas were VOCs-limited regime with decreased ozone concentration when reducing the emission of VOCs. On the contrary, the ozone concentration in downwind rural areas decreased with the reduction of NOx, and the reason may be the decrement of the accumulated precursors.

  12. Merged SAGE II, Ozone_cci and OMPS ozone profile dataset and evaluation of ozone trends in the stratosphere

    Directory of Open Access Journals (Sweden)

    V. F. Sofieva

    2017-10-01

    Full Text Available In this paper, we present a merged dataset of ozone profiles from several satellite instruments: SAGE II on ERBS, GOMOS, SCIAMACHY and MIPAS on Envisat, OSIRIS on Odin, ACE-FTS on SCISAT, and OMPS on Suomi-NPP. The merged dataset is created in the framework of the European Space Agency Climate Change Initiative (Ozone_cci with the aim of analyzing stratospheric ozone trends. For the merged dataset, we used the latest versions of the original ozone datasets. The datasets from the individual instruments have been extensively validated and intercompared; only those datasets which are in good agreement, and do not exhibit significant drifts with respect to collocated ground-based observations and with respect to each other, are used for merging. The long-term SAGE–CCI–OMPS dataset is created by computation and merging of deseasonalized anomalies from individual instruments. The merged SAGE–CCI–OMPS dataset consists of deseasonalized anomalies of ozone in 10° latitude bands from 90° S to 90° N and from 10 to 50 km in steps of 1 km covering the period from October 1984 to July 2016. This newly created dataset is used for evaluating ozone trends in the stratosphere through multiple linear regression. Negative ozone trends in the upper stratosphere are observed before 1997 and positive trends are found after 1997. The upper stratospheric trends are statistically significant at midlatitudes and indicate ozone recovery, as expected from the decrease of stratospheric halogens that started in the middle of the 1990s and stratospheric cooling.

  13. Tropospheric Ozone from the TOMS TDOT (TOMS-Direct-Ozone-in-Troposphere) Technique During SAFARI-2000

    Science.gov (United States)

    Stone, J. B.; Thompson, A. M.; Frolov, A. D.; Hudson, R. D.; Bhartia, P. K. (Technical Monitor)

    2002-01-01

    There are a number of published residual-type methods for deriving tropospheric ozone from TOMS (Total Ozone Mapping Spectrometer). The basic concept of these methods is that within a zone of constant stratospheric ozone, the tropospheric ozone column can be computed by subtracting stratospheric ozone from the TOMS Level 2 total ozone column, We used the modified-residual method for retrieving tropospheric ozone during SAFARI-2000 and found disagreements with in-situ ozone data over Africa in September 2000. Using the newly developed TDOT (TOMS-Direct-Ozone-in-Troposphere) method that uses TOMS radiances and a modified lookup table based on actual profiles during high ozone pollution periods, new maps were prepared and found to compare better to soundings over Lusaka, Zambia (15.5 S, 28 E), Nairobi and several African cities where MOZAIC aircraft operated in September 2000. The TDOT technique and comparisons are described in detail.

  14. A global analysis of the ozone deficit in the upper stratosphere and lower mesosphere

    Science.gov (United States)

    Eluszkiewicz, Janusz; Allen, Mark

    1993-01-01

    The global measurements of temperature, ozone, water vapor, and nitrogen dioxide acquired by the Limb Infrared Monitor of the Stratosphere (LIMS), supplemented by a precomputed distribution of chlorine monoxide, are used to test the balance between odd oxygen production and loss in the upper stratosphere and lower mesosphere. An efficient photochemical equilibrium model, whose validity is ascertained by comparison with the results from a fully time-dependent one-dimensional model at selected latitudes, is used in the calculations. The computed ozone abundances are systematically lower than observations for May 1-7, 1979, which suggests, contrary to the conclusions of other recent studies, a real problem in model simulations of stratospheric ozone.

  15. Surface ozone in the Colorado northern Front Range and the influence of oil and gas development during FRAPPE/DISCOVER-AQ in summer 2014

    Directory of Open Access Journals (Sweden)

    L. C. Cheadle

    2017-11-01

    Full Text Available High mixing ratios of ozone (O3 in the northern Front Range (NFR of Colorado are not limited to the urban Denver area but were also observed in rural areas where oil and gas activity is the primary source of O3 precursors. On individual days, oil and gas O3 precursors can contribute in excess of 30 ppb to O3 growth and can lead to exceedances of the EPA O3 National Ambient Air Quality Standard. Data used in this study were gathered from continuous surface O3 monitors for June–August 2013–2015 as well as additional flask measurements and mobile laboratories that were part of the FRAPPE/DISCOVER-AQ field campaign of July–August 2014. Overall observed O3 levels during the summer of 2014 were lower than in 2013, likely due to cooler and damper weather than an average summer. This study determined the median hourly surface O3 mixing ratio in the NFR on summer days with limited photochemical production to be approximately 45–55 ppb. Mobile laboratory and flask data collected on three days provide representative case studies of different O3 formation environments in and around Greeley, Colorado. Observations of several gases (including methane, ethane, CO, nitrous oxide along with O3 are used to identify sources of O3 precursor emissions. A July 23 survey demonstrated low O3 (45–60 ppb while August 3 and August 13 surveys recorded O3 levels of 75–80 ppb or more. August 3 exemplifies influence of moderate urban and high oil and gas O3 precursor emissions. August 13 demonstrates high oil and gas emissions, low agricultural emissions, and CO measurements that were well correlated with ethane from oil and gas, suggesting an oil and gas related activity as a NOx and O3 precursor source. Low isoprene levels indicated that they were not a significant contributor to O3 precursors measured during the case studies.

  16. Analyzing ground ozone formation regimes using a principal axis factoring method: A case study of Kladno (Czech Republic) industrial area

    Energy Technology Data Exchange (ETDEWEB)

    Malec, L.; Skacel, F. [Department of Gas, Coke and Air Protection, Institute of Chemical Technology in Prague, (Czech Republic)]. E-mail: Lukas.Malec@vscht.cz; Fousek, T. [Institute of Public Health, District of Central Czech Republic, Kladno (Czech Republic); Tekac, V. [Department of Gas, Coke and Air Protection, Institute of Chemical Technology in Prague, (Czech Republic); Kral, P. [Institute of Public Health, District of Central Czech Republic, Kladno (Czech Republic)

    2008-07-15

    Tropospheric ozone is a secondary air pollutant, changes in the ambient content of which are affected by both, the emission rates of primary pollutants and the variability of meteorological conditions. In this paper, we use two multivariate statistical methods to analyze the impact of the meteorological conditions associated with pollutant transformation processes. First, we evaluated the variability of the spatial and temporal distribution of ozone precursor parameters by using discriminant analysis (DA) in locations close to the industrial area of Kladno (a city in the Czech Republic). Second, we interpreted the data set by using factor analysis (FA) to examine the differences between ozone formation processes in summer and in winter. To avoid temperature dependency between the variables, as well as to describe tropospheric washout processes, we used water vapour content rather than the more commonly employed relative humidity parameter. In this way, we were able to successfully determine and subsequently evaluate the various processes of ozone formation, together with the distribution of ozone precursors. High air temperature, radiation and low water content relate to summer pollution episodes, while radiation and wind speed prove to be the most important parameters during winter. [Spanish] El ozono troposferico es un contaminante fotoquimico secundario cuyos contenidos estan influidos tanto por las razones de emision de las sustancias contaminantes primarias como por la variabilidad de las condiciones meteorologicas. En este trabajo utilizamos dos metodos estadisticos multivariados para el analisis de la influencia de las condiciones meteorologicas relacionadas con los procesos de transformacion de las sustancias contaminantes. Primero, estimamos la variabilidad de la descomposicion espacial y temporal de los precursores de ozono mediante el analisis discriminante (DA) en las areas cercanas a la zona industrial de Kladno (una ciudad de la Republica Checa

  17. A Review of Atmospheric Ozone and Current Thinking on the Antarctic Ozone Hole.

    Science.gov (United States)

    1987-01-01

    UNIVERSITY OF CALIFORNIA 0 A Review of Atmospheric ozone and Current Thinking on the Antartic Ozone Hole A thesis submitted in partial satisfaction of the...4. TI TLE (Pit 5,1tlfie) S. TYPE OF REPORT & PFRIOO COVERED A Review of Atmospheric Ozone and Current THESIS/DA/;J.At1AAU00 Thinking on the Antartic ...THESIS A Review of Atmospheric Ozone and Current Thinking on the Antartic Ozone Hole by Randolph Antoine Fix Master of Science in Atmospheric Science

  18. Ozone depletion calculations

    International Nuclear Information System (INIS)

    Luther, F.M.; Chang, J.S.; Wuebbles, D.J.; Penner, J.E.

    1992-01-01

    Models of stratospheric chemistry have been primarily directed toward an understanding of the behavior of stratospheric ozone. Initially this interest reflected the diagnostic role of ozone in the understanding of atmospheric transport processes. More recently, interest in stratospheric ozone has arisen from concern that human activities might affect the amount of stratospheric ozone, thereby affecting the ultraviolet radiation reaching the earth's surface and perhaps also affecting the climate with various potentially severe consequences for human welfare. This concern has inspired a substantial effort to develop both diagnostic and prognostic models of stratospheric ozone. During the past decade, several chemical agents have been determined to have potentially significant impacts on stratospheric ozone if they are released to the atmosphere in large quantities. These include oxides of nitrogen, oxides of hydrogen, chlorofluorocarbons, bromine compounds, fluorine compounds and carbon dioxide. In order to assess the potential impact of the perturbations caused by these chemicals, mathematical models have been developed to handle the complex coupling between chemical, radiative, and dynamical processes. Basic concepts in stratospheric modeling are reviewed

  19. Surface ozone seasonality under global change: Influence from dry deposition and isoprene emissions at northern mid-latitudes

    Science.gov (United States)

    Clifton, O.; Paulot, F.; Fiore, A. M.; Horowitz, L. W.; Malyshev, S.; Shevliakova, E.; Correa, G. J. P.; Lin, M.

    2017-12-01

    Identifying the contributions of nonlinear chemistry and transport to observed surface ozone seasonal cycles over land using global models relies on an accurate representation of ozone uptake by vegetation (dry deposition). It is well established that in the absence of ozone precursor emission changes, a warming climate will increase surface ozone in polluted regions, and that a rise in temperature-dependent isoprene emissions would exacerbate this "climate penalty". However, the influence of changes in ozone dry deposition, expected to evolve with climate and land use, is often overlooked in air quality projections. With a new scheme that represents dry deposition within the NOAA GFDL dynamic vegetation land model (LM3) coupled to the NOAA GFDL atmospheric chemistry-climate model (AM3), we simulate the impact of 21st century climate and land use on ozone dry deposition and isoprene emissions. This dry deposition parameterization is a version of the Wesely scheme, but uses parameters explicitly calculated by LM3 that respond to climate and land use (e.g., stomatal conductance, canopy interception of water, leaf area index). The parameterization includes a nonstomatal deposition dependence on humidity. We evaluate climatological present-day seasonal cycles of ozone deposition velocities and abundances with those observed at northern mid-latitude sites. With a set of 2010s and 2090s decadal simulations under a high climate warming scenario (RCP8.5) and a sensitivity simulation with well-mixed greenhouse gases following RCP8.5 but air pollutants held at 2010 levels (RCP8.5_WMGG), we examine changes in surface ozone seasonal cycles. We build on our previous findings, which indicate that strong reductions in anthropogenic NOx emissions under RCP8.5 cause the surface ozone seasonal cycle over the NE USA to reverse, shifting from a summer peak at present to a winter peak by 2100. Under RCP8.5_WMGG, we parse the separate effects of climate and land use on ozone dry

  20. Characterization of Fine Particulate Matter (PM) and Secondary PM Precursor Gases in the Mexico City Metropolitan Area

    Energy Technology Data Exchange (ETDEWEB)

    Molina, Luisa T.; Molina, Mario J.; Volkamer, Rainer; de Foy, Benjamin; Lei, Wenfang; Zavaka, Miguel; Velasco, Erik

    2008-10-31

    This project was one of three collaborating grants funded by DOE/ASP to characterize the fine particulate matter (PM) and secondary PM precursors in the Mexico City Metropolitan Area (MCMA) during the MILAGRO Campaign. The overall effort of MCMA-2006, one of the four components, focused on i) examination of the primary emissions of fine particles and precursor gases leading to photochemical production of atmospheric oxidants and secondary aerosol particles; ii) measurement and analysis of secondary oxidants and secondary fine PM production, with particular emphasis on secondary organic aerosol (SOA), and iii) evaluation of the photochemical and meteorological processes characteristic of the Mexico City Basin. The collaborative teams pursued the goals through three main tasks: i) analyses of fine PM and secondary PM precursor gaseous species data taken during the MCMA-2002/2003 campaigns and preparation of publications; ii) planning of the MILAGRO Campaign and deployment of the instrument around the MCMA; and iii) analysis of MCMA-2006 data and publication preparation. The measurement phase of the MILAGRO Campaign was successfully completed in March 2006 with excellent participation from the international scientific community and outstanding cooperation from the Mexican government agencies and institutions. The project reported here was led by the Massachusetts Institute of Technology/Molina Center for Energy and the Environment (MIT/MCE2) team and coordinated with DOE/ASP-funded collaborators at Aerodyne Research Inc., University of Colorado at Boulder and Montana State University. Currently 24 papers documenting the findings from this project have been published. The results from the project have improved significantly our understanding of the meteorological and photochemical processes contributing to the formation of ozone, secondary aerosols and other pollutants. Key findings from the MCMA-2003 include a vastly improved speciated emissions inventory from on

  1. Foliar nutrient status of Pinus ponderosa exposed to ozone and acid rain

    International Nuclear Information System (INIS)

    Anderson, P.D.; Houpis, J.L.J.

    1991-01-01

    A direct effect of foliar exposure to acid rain may be increased leaching of nutrient elements. Ozone exposure, through degradation of the cuticle and cellular membranes, may also result in increased nutrient leaching. To test these hypotheses, the foliar concentrations of 13 nutrient elements were monitored for mature branches of three clones of Pinus ponderosa exposed to ozone and/or acid rain. The three clones represented three distinct levels of phenotypic vigor. Branches were exposed to charcoal filtered, ambient, or 2 x ambient concentrations of ozone and received no acid rain (NAP), pH 5.1 rain (5.1), or pH 3.0 (3.0) rain. Following 10 months of continuous ozone exposure and 3 months of weekly rain applications, the concentrations of P and Mg differed significantly among rain treatments with a ranking of: 5.1 < NAP < 3.0. The S concentration increased with rain application regardless of pH. For the clones of moderate and low vigor, the concentration of N decreased with increasing rain acidity. There was no evidence of significant ozone or ozone x acid rain response. Among the three families, high phenotypic vigor was associated with significantly greater concentrations of N, P, K, Mg, B and An. These results indicate generally negligible leaching as a result of exposure to acid rain and/or ozone for one growing season. Increases in foliar concentrations of S, Mg and P are possibly the result of evaporative surface deposition from the rain solution

  2. OMI/Aura Ozone(O3) Total Column 1-Orbit L2 Swath 13x24 km V003 (OMTO3) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The Aura Ozone Monitoring Instrument (OMI) Level-2 Total Column Ozone Data Product OMTO3 (Version 003) is available from the NASA Goddard Earth Sciences Data and...

  3. Ozone kinetics in low-pressure discharges: vibrationally excited ozone and molecule formation on surfaces

    Science.gov (United States)

    Marinov, Daniil; Guerra, Vasco; Guaitella, Olivier; Booth, Jean-Paul; Rousseau, Antoine

    2013-10-01

    A combined experimental and modeling investigation of the ozone kinetics in the afterglow of pulsed direct current discharges in oxygen is carried out. The discharge is generated in a cylindrical silica tube of radius 1 cm, with short pulse durations between 0.5 and 2 ms, pressures in the range 1-5 Torr and discharge currents ˜40-120 mA. Time-resolved absolute concentrations of ground-state atoms and ozone molecules were measured simultaneously in situ, by two-photon absorption laser-induced fluorescence and ultraviolet absorption, respectively. The experiments were complemented by a self-consistent model developed to interpret the results and, in particular, to evaluate the roles of vibrationally excited ozone and of ozone formation on surfaces. It is found that vibrationally excited ozone, O_3^{*} , plays an important role in the ozone kinetics, leading to a decrease in the ozone concentration and an increase in its formation time. In turn, the kinetics of O_3^{*} is strongly coupled with those of atomic oxygen and O2(a 1Δg) metastables. Ozone formation at the wall does not contribute significantly to the total ozone production under the present conditions. Upper limits for the effective heterogeneous recombination probability of O atoms into ozone are established.

  4. Ozone kinetics in low-pressure discharges: vibrationally excited ozone and molecule formation on surfaces

    International Nuclear Information System (INIS)

    Marinov, Daniil; Guaitella, Olivier; Booth, Jean-Paul; Rousseau, Antoine; Guerra, Vasco

    2013-01-01

    A combined experimental and modeling investigation of the ozone kinetics in the afterglow of pulsed direct current discharges in oxygen is carried out. The discharge is generated in a cylindrical silica tube of radius 1 cm, with short pulse durations between 0.5 and 2 ms, pressures in the range 1–5 Torr and discharge currents ∼40–120 mA. Time-resolved absolute concentrations of ground-state atoms and ozone molecules were measured simultaneously in situ, by two-photon absorption laser-induced fluorescence and ultraviolet absorption, respectively. The experiments were complemented by a self-consistent model developed to interpret the results and, in particular, to evaluate the roles of vibrationally excited ozone and of ozone formation on surfaces. It is found that vibrationally excited ozone, O 3 * , plays an important role in the ozone kinetics, leading to a decrease in the ozone concentration and an increase in its formation time. In turn, the kinetics of O 3 * is strongly coupled with those of atomic oxygen and O 2 (a 1 Δ g ) metastables. Ozone formation at the wall does not contribute significantly to the total ozone production under the present conditions. Upper limits for the effective heterogeneous recombination probability of O atoms into ozone are established. (paper)

  5. Improvement of ozone yield by a multi-discharge type ozonizer using superposition of silent discharge plasma

    International Nuclear Information System (INIS)

    Song, Hyun-Jig; Chun, Byung-Joon; Lee, Kwang-Sik

    2004-01-01

    In order to improve ozone generation, we experimentally investigated the silent discharge plasma and ozone generation characteristics of a multi-discharge type ozonizer. Ozone in a multi-discharge type ozonizer is generated by superposition of a silent discharge plasma, which is simultaneously generated in separated discharge spaces. A multi-discharge type ozonizer is composed of three different kinds of superposed silent discharge type ozonizers, depending on the method of applying power to each electrode. We observed that the discharge period of the current pulse for a multi discharge type ozonizer can be longer than that of silent discharge type ozonizer with two electrodes and one gap. Hence, ozone generation is improved up to 17185 ppm and 783 g/kwh in the case of the superposed silent discharge type ozonizer for which an AC high voltages with a 180 .deg. phase difference were applied to the internal electrode and the external electrode, respectively, with the central electrode being grounded.

  6. Surface ozone pollution in Poland - observations and modelling support for a two-year assessment 2012-2013

    Science.gov (United States)

    Struzewska, Joanna; Kaminski, Jacek W.; Durka, Pawel

    2015-04-01

    The concentrations of near-surface ozone in terms of long term objectives and target values are exceeded at many monitoring sites in Poland. At the request of the Chief Inspectorate of Environmental Protection, an assessment of ozone impact on human health and ecosystems in Poland was undertaken, based on the GEM-AQ model calculations for the period 2012-2013. GEM-AQ (Kaminski et al., 2008) is a comprehensive chemical weather model where air quality processes (chemistry and aerosols) are implemented on-line in the operational weather prediction model developed at Environment Canada (Cote et al., 1998). For this project the model was run in a self-nesting mode with the target grid centered over Poland with the resolution of 5 km. The EMEP emission inventory was refined based on GIS information. Modelling results were evaluated against ozone and NO2 measurements from available monitoring stations in Poland using the DeltaTool developed in the scope of FAIRMODE. We will present exposure levels to high ozone concentrations in terms of number of days with exceeded target values as well as indices AOT40 and SOMO35. Differences between exposure diagnostics in 2012 and 2013 will be discussed.

  7. The determination and fate of disinfection by-products from ozonation of polluted raw water

    International Nuclear Information System (INIS)

    Huang, W.-J.; Fang, G.-C.; Wang, C.-C.

    2005-01-01

    The major disinfection by-products (DBPs) resulting from ozone treatment of polluted surface water were investigated. By-products of either health concern or which may contribute to biological instability of treated drinking water were investigated. The major DBPs were analyzed in two fractions: carbonyl compounds and brominated organic compounds. The natural organic matter (NOM) was also isolated and fractionated from polluted water for subsequent ozonation and DBPs identification under conditions of typical drinking treatment. The main identified carbonyl compounds were low molecular weight carboxylic acids, benzoic compounds, aliphatic aldehydes and odorous aldehydes, respectively. Brominated organics were also found in ozonated water, including bromoform (CHBr 3 ), monobromoacetic acid (MBAA), dibromoacetic acid (DBAA), 2,4-dibromophenol (2,4-DBP) and dibromoacetonitrile (DBAN), respectively. It was also found that the characteristic of organic precursors have significant influences on brominated organic by-products formation. Humic acid demonstrated the highest CHBr 3 , DBAA and 2,4-DBP formations, whereas hydrophilic neutral produced less CHBr 3 and 2,4-DBP than the rest of the organic fractions but produced the highest amount of DBAN. In addition to the other target compounds, a total of 59 different organic compounds were detected by means of gas chromatograph/high-resolution electron-impact mass spectrometry (GC/EI-MS) detection and tentatively identified using mass spectral library searching, mainly aromatics, acids/esters, alcohols, aldehydes, phthalates and amines/amino acids were analyzed. The percentage of elimination or formation levels reached during ozonation is also discussed in this study

  8. Long-term exposure to ambient ozone and mortality: a quantitative systematic review and meta-analysis of evidence from cohort studies.

    Science.gov (United States)

    Atkinson, R W; Butland, B K; Dimitroulopoulou, C; Heal, M R; Stedman, J R; Carslaw, N; Jarvis, D; Heaviside, C; Vardoulakis, S; Walton, H; Anderson, H R

    2016-02-23

    While there is good evidence for associations between short-term exposure to ozone and a range of adverse health outcomes, the evidence from narrative reviews for long-term exposure is suggestive of associations with respiratory mortality only. We conducted a systematic, quantitative evaluation of the evidence from cohort studies, reporting associations between long-term exposure to ozone and mortality. Cohort studies published in peer-reviewed journals indexed in EMBASE and MEDLINE to September 2015 and PubMed to October 2015 and cited in reviews/key publications were identified via search strings using terms relating to study design, pollutant and health outcome. Study details and estimate information were extracted and used to calculate standardised effect estimates expressed as HRs per 10 ppb increment in long-term ozone concentrations. 14 publications from 8 cohorts presented results for ozone and all-cause and cause-specific mortality. We found no evidence of associations between long-term annual O3 concentrations and the risk of death from all causes, cardiovascular or respiratory diseases, or lung cancer. 4 cohorts assessed ozone concentrations measured during the warm season. Summary HRs for cardiovascular and respiratory causes of death derived from 3 cohorts were 1.01 (95% CI 1.00 to 1.02) and 1.03 (95% CI 1.01 to 1.05) per 10 ppb, respectively. Our quantitative review revealed a paucity of independent studies regarding the associations between long-term exposure to ozone and mortality. The potential impact of climate change and increasing anthropogenic emissions of ozone precursors on ozone levels worldwide suggests further studies of the long-term effects of exposure to high ozone levels are warranted. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  9. Comparative study of ozonized olive oil and ozonized sunflower oil

    OpenAIRE

    Díaz,Maritza F.; Hernández,Rebeca; Martínez,Goitybell; Vidal,Genny; Gómez,Magali; Fernández,Harold; Garcés,Rafael

    2006-01-01

    In this study the ozonized olive and sunflower oils are chemical and microbiologically compared. These oils were introduced into a reactor with bubbling ozone gas in a water bath at room temperature until they were solidified. The peroxide, acidity and iodine values along with antimicrobial activity were determined. Ozonization effects on the fatty acid composition of these oils were analyzed using Gas-Liquid Chromatographic Technique. An increase in peroxidation and acidity values was observ...

  10. Effects of ozone-vegetation coupling on surface ozone air quality via biogeochemical and meteorological feedbacks

    Science.gov (United States)

    Sadiq, Mehliyar; Tai, Amos P. K.; Lombardozzi, Danica; Martin, Maria Val

    2017-02-01

    Tropospheric ozone is one of the most hazardous air pollutants as it harms both human health and plant productivity. Foliage uptake of ozone via dry deposition damages photosynthesis and causes stomatal closure. These foliage changes could lead to a cascade of biogeochemical and biogeophysical effects that not only modulate the carbon cycle, regional hydrometeorology and climate, but also cause feedbacks onto surface ozone concentration itself. In this study, we implement a semi-empirical parameterization of ozone damage on vegetation in the Community Earth System Model to enable online ozone-vegetation coupling, so that for the first time ecosystem structure and ozone concentration can coevolve in fully coupled land-atmosphere simulations. With ozone-vegetation coupling, present-day surface ozone is simulated to be higher by up to 4-6 ppbv over Europe, North America and China. Reduced dry deposition velocity following ozone damage contributes to ˜ 40-100 % of those increases, constituting a significant positive biogeochemical feedback on ozone air quality. Enhanced biogenic isoprene emission is found to contribute to most of the remaining increases, and is driven mainly by higher vegetation temperature that results from lower transpiration rate. This isoprene-driven pathway represents an indirect, positive meteorological feedback. The reduction in both dry deposition and transpiration is mostly associated with reduced stomatal conductance following ozone damage, whereas the modification of photosynthesis and further changes in ecosystem productivity are found to play a smaller role in contributing to the ozone-vegetation feedbacks. Our results highlight the need to consider two-way ozone-vegetation coupling in Earth system models to derive a more complete understanding and yield more reliable future predictions of ozone air quality.

  11. Validation of ozone monitoring instrument ultraviolet index against ground-based UV index in Kampala, Uganda.

    Science.gov (United States)

    Muyimbwa, Dennis; Dahlback, Arne; Ssenyonga, Taddeo; Chen, Yi-Chun; Stamnes, Jakob J; Frette, Øyvind; Hamre, Børge

    2015-10-01

    The Ozone Monitoring Instrument (OMI) overpass solar ultraviolet (UV) indices have been validated against the ground-based UV indices derived from Norwegian Institute for Air Research UV measurements in Kampala (0.31° N, 32.58° E, 1200 m), Uganda for the period between 2005 and 2014. An excessive use of old cars, which would imply a high loading of absorbing aerosols, could cause the OMI retrieval algorithm to overestimate the surface UV irradiances. The UV index values were found to follow a seasonal pattern with maximum values in March and October. Under all-sky conditions, the OMI retrieval algorithm was found to overestimate the UV index values with a mean bias of about 28%. When only days with radiation modification factor greater than or equal to 65%, 70%, 75%, and 80% were considered, the mean bias between ground-based and OMI overpass UV index values was reduced to 8%, 5%, 3%, and 1%, respectively. The overestimation of the UV index by the OMI retrieval algorithm was found to be mainly due to clouds and aerosols.

  12. Tropospheric Ozone Source Attribution in Southern California during Summer 2014 Based on Lidar Measurements and Model Simulations

    Science.gov (United States)

    Granados Munoz, Maria Jose; Johnson, Matthew S.; Leblanc, Thierry

    2016-01-01

    In the past decades, significant efforts have been made to increase tropospheric ozone long-term monitoring. A large number of ground-based, airborne and space-borne instruments are currently providing valuable data to contribute to better understand tropospheric ozone budget and variability. Nonetheless, most of these instruments provide in-situ surface and column-integrated data, whereas vertically resolved measurements are still scarce. Besides ozonesondes and aircraft, lidar measurements have proven to be valuable tropospheric ozone profilers. Using the measurements from the tropospheric ozone differential absorption lidar (DIAL) located at the JPL Table Mountain Facility, California, and the GEOS-Chem and GEOS-5 model outputs, the impact of the North American monsoon on tropospheric ozone during summer 2014 is investigated. The influence of the Monsoon lightning-induced NOx will be evaluated against other sources (e.g. local anthropogenic emissions and the stratosphere) using also complementary data such as backward-trajectories analysis, coincident water vapor lidar measurements, and surface ozone in-situ measurements.

  13. Estonian total ozone climatology

    Directory of Open Access Journals (Sweden)

    K. Eerme

    Full Text Available The climatological characteristics of total ozone over Estonia based on the Total Ozone Mapping Spectrometer (TOMS data are discussed. The mean annual cycle during 1979–2000 for the site at 58.3° N and 26.5° E is compiled. The available ground-level data interpolated before TOMS, have been used for trend detection. During the last two decades, the quasi-biennial oscillation (QBO corrected systematic decrease of total ozone from February–April was 3 ± 2.6% per decade. Before 1980, a spring decrease was not detectable. No decreasing trend was found in either the late autumn ozone minimum or in the summer total ozone. The QBO related signal in the spring total ozone has an amplitude of ± 20 DU and phase lag of 20 months. Between 1987–1992, the lagged covariance between the Singapore wind and the studied total ozone was weak. The spring (April–May and summer (June–August total ozone have the best correlation (coefficient 0.7 in the yearly cycle. The correlation between the May and August total ozone is higher than the one between the other summer months. Seasonal power spectra of the total ozone variance show preferred periods with an over 95% significance level. Since 1986, during the winter/spring, the contribution period of 32 days prevails instead of the earlier dominating 26 days. The spectral densities of the periods from 4 days to 2 weeks exhibit high interannual variability.

    Key words. Atmospheric composition and structure (middle atmosphere – composition and chemistry; volcanic effects – Meteorology and atmospheric dynamics (climatology

  14. Dobson spectrophotometer ozone measurements during international ozone rocketsonde intercomparison

    Science.gov (United States)

    Parsons, C. L.

    1980-01-01

    Measurements of the total ozone content of the atmosphere, made with seven ground based instruments at a site near Wallops Island, Virginia, are discussed in terms for serving as control values with which the rocketborne sensor data products can be compared. These products are profiles of O3 concentration with altitude. By integrating over the range of altitudes from the surface to the rocket apogee and by appropriately estimating the residual ozone amount from apogee to the top of the atmosphere, a total ozone amount can be computed from the profiles that can be directly compared with the ground based instrumentation results. Dobson spectrophotometers were used for two of the ground-based instruments. Preliminary data collected during the IORI from Dobson spectrophotometers 72 and 38 are presented. The agreement between the two and the variability of total ozone overburden through the experiment period are discussed.

  15. LaRC Modeling of Ozone Formation in San Antonio, Texas

    Science.gov (United States)

    Guo, F.; Griffin, R. J.; Bui, A.; Schulze, B.; Wallace, H. W., IV; Flynn, J. H., III; Erickson, M.; Kotsakis, A.; Alvarez, S. L.; Usenko, S.; Sheesley, R. J.; Yoon, S.

    2017-12-01

    Ozone (O3) is one of the most important trace species within the troposphere and results from photochemistry involving emissions from a complex array of sources. Ground-level O3 is detrimental to ecosystems and causes a variety of human health problems including respiratory irritation, asthma and reduction in lung capacity. However, the O3 Design Value in San Antonio, Texas, was in violation of the federal threshold set by the EPA (70 ppb, 8-hr max) based on the average for the most recent three-year period (2014-2016). To understand the sources of high O3 concentrations in this nonattainment area, we assembled and deployed a mobile air quality laboratory and operated it in two locations in the southeast (Traveler's World RV Park) and northwest (University of Texas at San Antonio) of downtown San Antonio during summer 2017 to measure O3 and its precursors, including total nitrogen oxides (NOx) and volatile organic compounds (VOCs). Additional measurements included temperature, relative humidity, pressure, solar radiation, wind speed, wind direction, total reactive nitrogen (NOy), carbon monoxide (CO), and aerosol composition and concentration. We will use the campaign data and the NASA Langley Research Center (LaRC) Zero-Dimensional Box Model (Crawford et al., 1999; Olson et al., 2006) to calculate O3 production rate, NOx and hydroxyl radical chain length, and NOx versus VOCs sensitivity at different times of a day with different photochemical and meteorological conditions. A key to our understanding is to combine model results with measurements of precursor gases, particle chemistry and particle size to support the identification of O3 sources, its major formation pathways, and how the ozone production efficiency (OPE) depends on various factors. The resulting understanding of the causes of high O3 concentrations in the San Antonio area will provide insight into future air quality protection.

  16. Photo-chemical transport modelling of tropospheric ozone: A review

    Science.gov (United States)

    Sharma, Sumit; Sharma, Prateek; Khare, Mukesh

    2017-06-01

    Ground level ozone (GLO), a secondary pollutant having adverse impact on human health, ecology, and agricultural productivity, apart from being a major contributor to global warming, has been a subject matter of several studies. In order to identify appropriate strategies to control GLO levels, accurate assessment and prediction is essential, for which elaborate simulation and modelling is required. Several studies have been undertaken in the past to simulate GLO levels at different scales and for various applications. It is important to evaluate these studies, widely spread over in literature. This paper aims to critically review various studies that have been undertaken, especially in the past 15 years (2000-15) to model GLO. The review has been done of the studies that range over different spatial scales - urban to regional and continental to global. It also includes a review of performance evaluation and sensitivity analysis of photo-chemical transport models in order to assess the extent of application of these models and their predictive capability. The review indicates following major findings: (a) models tend to over-estimate the night-time GLO concentrations due to limited titration of GLO with NO within the model; (b) dominance of contribution from far-off regional sources to average ozone concentration in the urban region and higher contribution of local sources during days of high ozone episodes; requiring strategies for controlling precursor emissions at both regional and local scales; (c) greater influence of NOx over VOC in export of ozone from urban regions due to shifting of urban plumes from VOC-sensitive regime to NOx-sensitive as they move out from city centres to neighbouring rural regions; (d) models with finer resolution inputs perform better to a certain extent, however, further improvement in resolutions (beyond 10 km) did not show improvement always; (e) future projections show an increase in GLO concentrations mainly due to rise in

  17. The wireless networking system of Earthquake precursor mobile field observation

    Science.gov (United States)

    Wang, C.; Teng, Y.; Wang, X.; Fan, X.; Wang, X.

    2012-12-01

    The mobile field observation network could be real-time, reliably record and transmit large amounts of data, strengthen the physical signal observations in specific regions and specific period, it can improve the monitoring capacity and abnormal tracking capability. According to the features of scatter everywhere, a large number of current earthquake precursor observation measuring points, networking technology is based on wireless broadband accessing McWILL system, the communication system of earthquake precursor mobile field observation would real-time, reliably transmit large amounts of data to the monitoring center from measuring points through the connection about equipment and wireless accessing system, broadband wireless access system and precursor mobile observation management center system, thereby implementing remote instrument monitoring and data transmition. At present, the earthquake precursor field mobile observation network technology has been applied to fluxgate magnetometer array geomagnetic observations of Tianzhu, Xichang,and Xinjiang, it can be real-time monitoring the working status of the observational instruments of large area laid after the last two or three years, large scale field operation. Therefore, it can get geomagnetic field data of the local refinement regions and provide high-quality observational data for impending earthquake tracking forecast. Although, wireless networking technology is very suitable for mobile field observation with the features of simple, flexible networking etc, it also has the phenomenon of packet loss etc when transmitting a large number of observational data due to the wireless relatively weak signal and narrow bandwidth. In view of high sampling rate instruments, this project uses data compression and effectively solves the problem of data transmission packet loss; Control commands, status data and observational data transmission use different priorities and means, which control the packet loss rate within

  18. Limitations of the removal of cyanide from coking wastewater by ozonation and by the hydrogen peroxide-ozone process.

    Science.gov (United States)

    Pueyo, N; Miguel, N; Ovelleiro, J L; Ormad, M P

    The purpose of this study is to compare the efficiency of ozonation and the hydrogen peroxide-ozone process for the removal of cyanide from coking wastewater. The most efficient oxidation process is combined with coagulation-flocculation-decantation and lime-soda ash softening pretreatments. The oxidation in aqueous solution and industrial wastewater (at pH 9.5-12.3) by O3 was carried out using a range of concentration of consumed O3 from 10 to 290 mg/L. A molar ratio of H2O2/O3 from 0.1 to 5.2 with different concentrations of O3 constants was used for the H2O2-O3 process. The maximum cyanide removal obtained in coking wastewater was 90% using a mass ratio of O3/CN(-) of 9.5. Using lower concentrations of O3, cyanide is not removed and can even be generated due to the presence of other cyanide precursor organic micropollutants in the industrial matrix. The concentration of O3 is reduced to half for the same cyanide removal efficiency if the pretreatments are applied to reduce the carbonate and bicarbonate ions. The cyanide removal efficiency in coking wastewater is not improved if the O3 is combined with the H2O2. However, the preliminary cyanide removal treatment in aqueous solution showed an increase in the cyanide removal efficiency for the H2O2-O3 process.

  19. Total ozone column derived from GOME and SCIAMACHY using KNMI retrieval algorithms: Validation against Brewer measurements at the Iberian Peninsula

    Science.gov (United States)

    Antón, M.; Kroon, M.; López, M.; Vilaplana, J. M.; Bañón, M.; van der A, R.; Veefkind, J. P.; Stammes, P.; Alados-Arboledas, L.

    2011-11-01

    This article focuses on the validation of the total ozone column (TOC) data set acquired by the Global Ozone Monitoring Experiment (GOME) and the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) satellite remote sensing instruments using the Total Ozone Retrieval Scheme for the GOME Instrument Based on the Ozone Monitoring Instrument (TOGOMI) and Total Ozone Retrieval Scheme for the SCIAMACHY Instrument Based on the Ozone Monitoring Instrument (TOSOMI) retrieval algorithms developed by the Royal Netherlands Meteorological Institute. In this analysis, spatially colocated, daily averaged ground-based observations performed by five well-calibrated Brewer spectrophotometers at the Iberian Peninsula are used. The period of study runs from January 2004 to December 2009. The agreement between satellite and ground-based TOC data is excellent (R2 higher than 0.94). Nevertheless, the TOC data derived from both satellite instruments underestimate the ground-based data. On average, this underestimation is 1.1% for GOME and 1.3% for SCIAMACHY. The SCIAMACHY-Brewer TOC differences show a significant solar zenith angle (SZA) dependence which causes a systematic seasonal dependence. By contrast, GOME-Brewer TOC differences show no significant SZA dependence and hence no seasonality although processed with exactly the same algorithm. The satellite-Brewer TOC differences for the two satellite instruments show a clear and similar dependence on the viewing zenith angle under cloudy conditions. In addition, both the GOME-Brewer and SCIAMACHY-Brewer TOC differences reveal a very similar behavior with respect to the satellite cloud properties, being cloud fraction and cloud top pressure, which originate from the same cloud algorithm (Fast Retrieval Scheme for Clouds from the Oxygen A-Band (FRESCO+)) in both the TOSOMI and TOGOMI retrieval algorithms.

  20. Environmental ozone exposure and oxidative DNA damage in adult residents of Florence, Italy

    Energy Technology Data Exchange (ETDEWEB)

    Palli, Domenico, E-mail: d.palli@ispo.toscana.i [Molecular and Nutritional Epidemiology Unit, Cancer Prevention and Research Institute (ISPO), Via Cosimo il Vecchio 2, 50139 Florence (Italy); Sera, Francesco, E-mail: f.sera@ispo.toscana.i [Molecular and Nutritional Epidemiology Unit, Cancer Prevention and Research Institute (ISPO), Via Cosimo il Vecchio 2, 50139 Florence (Italy); Giovannelli, Lisa, E-mail: lisag@pharm.unifi.i [Department of Pharmacology, University of Florence, Viale G.Pieraccini 6, 50139 Florence (Italy); Masala, Giovanna, E-mail: g.masala@ispo.toscana.i [Molecular and Nutritional Epidemiology Unit, Cancer Prevention and Research Institute (ISPO), Via Cosimo il Vecchio 2, 50139 Florence (Italy); Grechi, Daniele [Regional Environmental Protection Agency of Tuscany (ARPAT), Via Porpora 22, 50144 Florence (Italy); Bendinelli, Benedetta, E-mail: b.bendinelli@ispo.toscana.i [Molecular and Nutritional Epidemiology Unit, Cancer Prevention and Research Institute (ISPO), Via Cosimo il Vecchio 2, 50139 Florence (Italy); Caini, Saverio, E-mail: s.caini@ispo.toscana.i [Molecular and Nutritional Epidemiology Unit, Cancer Prevention and Research Institute (ISPO), Via Cosimo il Vecchio 2, 50139 Florence (Italy); Dolara, Piero, E-mail: piero.dolara@unifi.i [Department of Pharmacology, University of Florence, Viale G.Pieraccini 6, 50139 Florence (Italy); Saieva, Calogero, E-mail: c.saieva@ispo.toscana.i [Molecular and Nutritional Epidemiology Unit, Cancer Prevention and Research Institute (ISPO), Via Cosimo il Vecchio 2, 50139 Florence (Italy)

    2009-05-15

    In 71 adults residing in Florence, Italy, enrolled in a prospective study, we investigated the correlation between individual levels of oxidative DNA damage detected by the Comet assay in circulating lymphocytes, and a specific ozone exposure score calculated in 10 different time-windows (0-5 to 0-90 days) before blood drawing, based on daily measurements provided by the local environmental monitoring system. Overall, statistically significant positive correlations between average ozone concentrations and DNA damage emerged in almost all time-windows considered; correlations were more evident among males, non-smokers, and traffic-exposed workers. Multivariate regression analyses taking into account selected individual characteristics, showed an independent effect on DNA damage of average ozone concentrations in the last 60-90 days before blood drawing. Local residents showed a divergent pattern with correlations restricted to shorter time-windows. Our results suggest that ozone concentrations at ground levels modulate oxidative DNA damage in circulating lymphocytes of residents of polluted areas. - Ozone concentrations over the 60-90 days before blood drawing correlated with DNA damage in circulating lymphocytes of adults living in the metropolitan area of Florence, Italy.

  1. Environmental ozone exposure and oxidative DNA damage in adult residents of Florence, Italy

    International Nuclear Information System (INIS)

    Palli, Domenico; Sera, Francesco; Giovannelli, Lisa; Masala, Giovanna; Grechi, Daniele; Bendinelli, Benedetta; Caini, Saverio; Dolara, Piero; Saieva, Calogero

    2009-01-01

    In 71 adults residing in Florence, Italy, enrolled in a prospective study, we investigated the correlation between individual levels of oxidative DNA damage detected by the Comet assay in circulating lymphocytes, and a specific ozone exposure score calculated in 10 different time-windows (0-5 to 0-90 days) before blood drawing, based on daily measurements provided by the local environmental monitoring system. Overall, statistically significant positive correlations between average ozone concentrations and DNA damage emerged in almost all time-windows considered; correlations were more evident among males, non-smokers, and traffic-exposed workers. Multivariate regression analyses taking into account selected individual characteristics, showed an independent effect on DNA damage of average ozone concentrations in the last 60-90 days before blood drawing. Local residents showed a divergent pattern with correlations restricted to shorter time-windows. Our results suggest that ozone concentrations at ground levels modulate oxidative DNA damage in circulating lymphocytes of residents of polluted areas. - Ozone concentrations over the 60-90 days before blood drawing correlated with DNA damage in circulating lymphocytes of adults living in the metropolitan area of Florence, Italy.

  2. The ozone backlash

    International Nuclear Information System (INIS)

    Taubes, G.

    1993-01-01

    While evidence for the role of chlorofluorocarbons in ozone depletion grows stronger, researchers have recently been subjected to vocal public criticism of their theories-and their motives. Their understanding of the mechanisms of ozone destruction-especially the annual ozone hole that appears in the Antarctic-has grown stronger, yet everywhere they go these days, they seem to be confronted by critics attacking their theories as baseless. For instance, Rush Limbaugh, the conservative political talk-show host and now-best-selling author of The Way Things Ought to Be, regularly insists that the theory of ozone depletion by CFCs is a hoax: bladerdash and poppycock. Zoologist Dixy Lee Ray, former governor of the state of Washington and former head of the Atomic Energy Commission, makes the same argument in her book, Trashing the Planet. The Wall Street Journal and National Review have run commentaries by S. Fred Singer, a former chief scientists for the Department of Transportation, purporting to shoot holes in the theory of ozone depletion. Even the June issue of Omni, a magazine with a circulation of more than 1 million that publishes a mixture of science and science fiction, printed a feature article claiming to expose ozone research as a politically motivated scam

  3. Heterodyne spectrophotometry of ozone in the 9.6-micron band using a tunable diode laser

    Science.gov (United States)

    Mcelroy, C. T.; Goldman, A.; Fogal, P. F.; Murcray, D. G.

    1990-01-01

    Tunable diode laser heterodyne spectrophotometry (TDLHS) has been used to make extremely high resolution (0.0003/cm) solar spectra in the 9.6-micron ozone band. Observations have shown that a signal-to-noise ratio of 120:1 (about 30 percent of theoretical) for an integration time of 1/8 s can be achieved at a resolution of 0.0013 wave numbers. The spectral data have been inverted to yield a total column amount of ozone, in good agreement with that measured at the nearby NOAA ozone monitoring facility in Boulder, Colorado. Line positions for several ozone lines in the spectral region 996-997/cm are reported. Recent improvements have produced a signal-to-noise ratio of 95:1 (about 40 percent of theoretical) at 0.0003/cm and extended the range of wavelengths which can be observed.

  4. A Global Ozone Climatology from Ozone Soundings via Trajectory Mapping: A Stratospheric Perspective

    Science.gov (United States)

    Liu, J. J.; Tarasick, D. W.; Fioletov, V. E.; McLinden, C.; Zhao, T.; Gong, S.; Sioris, G.; Jin, J. J.; Liu, G.; Moeini, O.

    2013-01-01

    This study explores a domain-filling trajectory approach to generate a global ozone climatology from sparse ozonesonde data. Global ozone soundings of 51,898 profiles at 116 stations over 44 years (1965-2008) are used, from which forward and backward trajectories are performed for 4 days, driven by a set of meteorological reanalysis data. Ozone mixing ratios of each sounding from the surface to 26 km altitude are assigned to the entire path along the trajectory. The resulting global ozone climatology is archived monthly for five decades from the 1960s to the 2000s with grids of 5 degree 5 degree 1 km (latitude, longitude, and altitude). It is also archived yearly from 1965 to 2008. This climatology is validated at 20 ozonesonde stations by comparing the actual ozone sounding profile with that found through the trajectories, using the ozone soundings at all the stations except one being tested. The two sets of profiles are in good agreement, both individually with correlation coefficients between 0.975 and 0.998 and root mean square (RMS) differences of 87 to 482 ppbv, and overall with a correlation coefficient of 0.991 and an RMS of 224 ppbv. The ozone climatology is also compared with two sets of satellite data, from the Satellite Aerosol and Gas Experiment (SAGE) and the Optical Spectrography and InfraRed Imager System (OSIRIS). Overall, the ozone climatology compares well with SAGE and OSIRIS data by both seasonal and zonal means. The mean difference is generally under 20 above 15 km. The comparison is better in the northern hemisphere, where there are more ozonesonde stations, than in the southern hemisphere; it is also better in the middle and high latitudes than in the tropics, where assimilated winds are imperfect in some regions. This ozone climatology can capture known features in the stratosphere, as well as seasonal and decadal variations of these features. Furthermore, it provides a wealth of detail about longitudinal variations in the stratosphere such

  5. A Compact Mobile Ozone Lidar for Atmospheric Ozone and Aerosol Profiling

    Science.gov (United States)

    De Young, Russell; Carrion, William; Pliutau, Denis

    2014-01-01

    A compact mobile differential absorption lidar (DIAL) system has been developed at NASA Langley Research Center to provide ozone, aerosol and cloud atmospheric measurements in a mobile trailer for ground-based atmospheric ozone air quality campaigns. This lidar is integrated into the Tropospheric Ozone Lidar Network (TOLNet) currently made up of four other ozone lidars across the country. The lidar system consists of a UV and green laser transmitter, a telescope and an optical signal receiver with associated Licel photon counting and analog channels. The laser transmitter consist of a Q-switched Nd:YLF inter-cavity doubled laser pumping a Ce:LiCAF tunable UV laser with all the associated power and lidar control support units on a single system rack. The system has been configured to enable mobile operation from a trailer and was deployed to Denver, CO July 15-August 15, 2014 supporting the DISCOVER-AQ campaign. Ozone curtain plots and the resulting science are presented.

  6. Importance of Ship Emissions to Local Summertime Ozone Production in the Mediterranean Marine Boundary Layer: A Modeling Study

    Directory of Open Access Journals (Sweden)

    Christian N. Gencarelli

    2014-12-01

    Full Text Available Ozone concentrations in the Mediterranean area regularly exceed the maximum levels set by the EU Air Quality Directive, 2008/50/CE, a maximum 8-h mean of 120 μg·m-3, in the summer, with consequences for both human health and agriculture. There are a number of reasons for this: the particular geographical and meteorological conditions in the Mediterranean play a part, as do anthropogenic ozone precursor emissions from around the Mediterranean and continental Europe. Ozone concentrations measured on-board the Italian Research Council’s R. V. Urania during summer oceanographic campaigns between 2000 and 2010 regularly exceeded 60 ppb, even at night. The WRF/Chem (Weather Research and Forecasting (WRF model coupled with Chemistrymodel has been used to simulate tropospheric chemistry during the periods of the measurement campaigns, and then, the same simulations were repeated, excluding the contribution of maritime traffic in the Mediterranean to the anthropogenic emissions inventory. The differences in the model output suggest that, in large parts of the coastal zone of the Mediterranean, ship emissions Atmosphere 2014, 5 938 contribute to 3 and 12 ppb to ground level daily average ozone concentrations. Near busy shipping lanes, up to 40 ppb differences in the hourly average ozone concentrations were found. It seems that ship emissions could be a significant factor in the exceedance of the EU directive on air quality in large areas of the Mediterranean Basin.

  7. Urban and Rural Ozone Pollution Over Lusaka (Zambia, 15.5S, 25E) During SAFARI-2000 (September 2000)

    Science.gov (United States)

    Thompson, Anne M.; Herman, J. R.; Witte, J. C.; Phahlane, A.; Coetzee, G. J. R.; Mukula, C.; Hudson, R. D.; Frolov, A. D.; Bhartia, P. K. (Technical Monitor)

    2001-01-01

    In early September, throughout south central Africa, seasonal clearing of dry vegetation and the production of charcoal for cooking leads to intense smoke haze and ozone formation. Ozone soundings made over Lusaka during a six-day period in early September 2000 recorded layers of high ozone (greater than 125 ppbv at 5 km) during two stagnant periods, interspersed by a frontal passage that reduced boundary layer ozone by 30 percent. Smoke aerosol column variations aloft and total ozone were monitored by a sun photometer. During the 6-day measurement period, surface ozone concentrations ranged from 50-95 ppbv and integrated tropospheric ozone from the soundings was 39- 54 Dobson Units (note 1.3 km elevation at the launch site). High ozone concentrations above the mixed and inversion layers were advected from rural burning regions in western Zambia where SAFARI aircraft and ground-based instruments observed intense biomass fires and elevated aerosol and trace gas amounts. TOMS tropospheric ozone and smoke aerosols products show the distribution of biomass burning and associated pollution throughout southern Africa in September 2000. Animations of satellite images and trajectories confirm pollutant recirculation over south central African fires, exit of ozone from Mozambique and Tanzania to the Indian Ocean and the characteristic buildup of tropospheric ozone over the Atlantic from western African outflow.

  8. Ozone: The secret greenhouse gas

    International Nuclear Information System (INIS)

    Berntsen, Terje; Tjernshaugen, Andreas

    2001-01-01

    The atmospheric ozone not only protects against harmful ultraviolet radiation; it also contributes to the greenhouse effect. Ozone is one of the jokers to make it difficult to calculate the climatic effect of anthropogenic emissions. The greenhouse effect and the ozone layer should not be confused. The greenhouse effect creates problems when it becomes enhanced, so that the earth becomes warmer. The problem with the ozone layer, on the contrary, is that it becomes thinner and so more of the harmful ultraviolet radiation gets through to the earth. However, ozone is also a greenhouse gas and so the greenhouse effect and the ozone layer are connected

  9. New dynamic NNORSY ozone profile climatology

    Science.gov (United States)

    Kaifel, A. K.; Felder, M.; Declercq, C.; Lambert, J.-C.

    2012-01-01

    Climatological ozone profile data are widely used as a-priori information for total ozone using DOAS type retrievals as well as for ozone profile retrieval using optimal estimation, for data assimilation or evaluation of 3-D chemistry-transport models and a lot of other applications in atmospheric sciences and remote sensing. For most applications it is important that the climatology represents not only long term mean values but also the links between ozone and dynamic input parameters. These dynamic input parameters should be easily accessible from auxiliary datasets or easily measureable, and obviously should have a high correlation with ozone. For ozone profile these parameters are mainly total ozone column and temperature profile data. This was the outcome of a user consultation carried out in the framework of developing a new, dynamic ozone profile climatology. The new ozone profile climatology is based on the Neural Network Ozone Retrieval System (NNORSY) widely used for ozone profile retrieval from UV and IR satellite sounder data. NNORSY allows implicit modelling of any non-linear correspondence between input parameters (predictors) and ozone profile target vector. This paper presents the approach, setup and validation of a new family of ozone profile climatologies with static as well as dynamic input parameters (total ozone and temperature profile). The neural network training relies on ozone profile measurement data of well known quality provided by ground based (ozonesondes) and satellite based (SAGE II, HALOE, and POAM-III) measurements over the years 1995-2007. In total, four different combinations (modes) for input parameters (date, geolocation, total ozone column and temperature profile) are available. The geophysical validation spans from pole to pole using independent ozonesonde, lidar and satellite data (ACE-FTS, AURA-MLS) for individual and time series comparisons as well as for analysing the vertical and meridian structure of different modes of

  10. Treatment of Egyptian Maghara coal by plasma ozone synthesized by silent discharge

    CERN Document Server

    Salem, M A; Garamoon, A A; Hassouba, M A

    2003-01-01

    A sample of pyrite rich bituminous coal collected from the main coal seam of Maghara mine, northern sinai, was treated by ozone plasma. The latter was synthesized using silent discharge method (10 kv a.c. and 50 hz). The room temperature Moessbauer spectra of untreated coal sample was easily fitted to two doublet, whose parameters matched those of pyrite (FeS sub 2) and sulfate (FeSO sub 4.H sub 2 O) in addition to hematite. After treatment by ozone plasma, a doublet ascribed to pyrite was observed. The extent of pyrite oxidation to jarosite (Fe sub 2 (SO sub 4) sub 3. nH sub 2 O) was monitored by their relative spectral areas, the incomplete oxidation of pyrite may be attributed to the presence of calcium sulfate layer which acts a screen of ozone.

  11. Ozone Laminae and Their Entrainment Into a Valley Boundary Layer, as Observed From a Mountaintop Monitoring Station, Ozonesondes, and Aircraft Over California's San Joaquin Valley

    Science.gov (United States)

    Faloona, I. C.; Conley, S. A.; Caputi, D.; Trousdell, J.; Chiao, S.; Eiserloh, A. J., Jr.; Clark, J.; Iraci, L. T.; Yates, E. L.; Marrero, J. E.; Ryoo, J. M.; McNamara, M. E.

    2016-12-01

    The San Joaquin Valley of California is wide ( 75 km) and long ( 400 km), and is situated under strong atmospheric subsidence due, in part, to the proximity of the midlatitude anticyclone of the Pacific High. The capping effect of this subsidence is especially prominent during the warm season when ground level ozone is a serious air quality concern across the region. While relatively clean marine boundary layer air is primarily funneled into the valley below the strong subsidence inversion at significant gaps in the upwind Coast Range mountains, airflow aloft also spills over these barriers and mixes into the valley from above. Because this transmountain flow occurs under the influence of synoptic subsidence it tends to present discrete, laminar sheets of differing air composition above the valley boundary layer. Meanwhile, although the boundary layers tend to remain shallow due to the prevailing subsidence, orographic and anabatic venting of valley boundary layer air around the basin whips up a complex admixture of regional air masses into a "buffer layer" just above the boundary layer (zi) and below the lower free troposphere. We present scalar data of widely varying lifetimes including ozone, methane, NOx, and thermodynamic observations from upwind and within the San Joaquin Valley to better explain this layering and its subsequent erosion into the valley boundary layer via entrainment. Data collected at a mountaintop monitoring station on Chews Ridge in the Coast Range, by coastal ozonesondes, and aircraft are analyzed to document the dynamic layering processes around the complex terrain surrounding the valley. Particular emphasis will be made on observational methods whereby distal ozone can be distinguished from the regional ozone to better understand the influence of exogenous sources on air quality in the valley.

  12. Tropospheric ozone over a tropical Atlantic station in the Northern Hemisphere: Paramaribo, Surinam (6°N, 55°W)

    NARCIS (Netherlands)

    Peters, W.; Krol, M. C.; Fortuin, J. P. F.; Kelder, H. M.; Thompson, A. M.; Becker, C. R.; Lelieveld, J.; Crutzen, P. J.

    2004-01-01

    We present an analysis of 2.5 yr of weekly ozone soundings conducted at a new monitoring station in Paramaribo, Surinam (6°N, 55°W). This is currently one of only three ozone sounding stations in the Northern Hemisphere (NH) tropics, and the only one in the equatorial Atlantic region. Paramaribo is

  13. Use of a heated graphite scrubber as a means of reducing interferences in UV-absorbance measurements of atmospheric ozone

    Directory of Open Access Journals (Sweden)

    A. A. Turnipseed

    2017-06-01

    Full Text Available A new solid-phase scrubber for use in conventional ozone (O3 photometers was investigated as a means of reducing interferences from other UV-absorbing species and water vapor. It was found that when heated to 100–130 °C, a tubular graphite scrubber efficiently removed up to 500 ppb ozone and ozone monitors using the heated graphite scrubber were found to be less susceptible to interferences from water vapor, mercury vapor, and aromatic volatile organic compounds (VOCs compared to conventional metal oxide scrubbers. Ambient measurements from a graphite scrubber-equipped photometer and a co-located Federal equivalent method (FEM ozone analyzer showed excellent agreement over 38 days of measurements and indicated no loss in the scrubber's ability to remove ozone when operated at 130 °C. The use of a heated graphite scrubber was found to reduce the interference from mercury vapor to ≤ 3 % of that obtained using a packed-bed Hopcalite scrubber. For a series of substituted aromatic compounds (ranging in volatility and absorption cross section at 253.7 nm, the graphite scrubber was observed to consistently exhibit reduced levels of interference, typically by factors of 2.5 to 20 less than with Hopcalite. Conventional solid-phase scrubbers also exhibited complex VOC adsorption and desorption characteristics that were dependent upon the relative humidity (RH, volatility of the VOC, and the available surface area of the scrubber. This complex behavior involving humidity is avoided by use of a heated graphite scrubber. These results suggest that heated graphite scrubbers could be substituted in most ozone photometers as a means of reducing interferences from other UV-absorbing species found in the atmosphere. This could be particularly important in ozone monitoring for compliance with the United States (U.S. Clean Air Act or for use in VOC-rich environments such as in smog chambers and monitoring indoor air quality.

  14. Estimates of Free-tropospheric NO2 Abundance from the Aura Ozone Monitoring Instrument (OMI) Using Cloud Slicing Technique

    Science.gov (United States)

    Choi, S.; Joiner, J.; Krotkov, N. A.; Choi, Y.; Duncan, B. N.; Celarier, E. A.; Bucsela, E. J.; Vasilkov, A. P.; Strahan, S. E.; Veefkind, J. P.; Cohen, R. C.; Weinheimer, A. J.; Pickering, K. E.

    2013-12-01

    Total column measurements of NO2 from space-based sensors are of interest to the atmospheric chemistry and air quality communities; the relatively short lifetime of near-surface NO2 produces satellite-observed hot-spots near pollution sources including power plants and urban areas. However, estimates of NO2 concentrations in the free-troposphere, where lifetimes are longer and the radiative impact through ozone formation is larger, are severely lacking. Such information is critical to evaluate chemistry-climate and air quality models that are used for prediction of the evolution of tropospheric ozone and its impact of climate and air quality. Here, we retrieve free-tropospheric NO2 volume mixing ratio (VMR) using the cloud slicing technique. We use cloud optical centroid pressures (OCPs) as well as collocated above-cloud vertical NO2 columns (defined as the NO2 column from top of the atmosphere to the cloud OCP) from the Ozone Monitoring Instrument (OMI). The above-cloud NO2 vertical columns used in our study are retrieved independent of a priori NO2 profile information. In the cloud-slicing approach, the slope of the above-cloud NO2 column versus the cloud optical centroid pressure is proportional to the NO2 volume mixing ratio (VMR) for a given pressure (altitude) range. We retrieve NO2 volume mixing ratios and compare the obtained NO2 VMRs with in-situ aircraft profiles measured during the NASA Intercontinental Chemical Transport Experiment Phase B (INTEX-B) campaign in 2006. The agreement is good when proper data screening is applied. In addition, the OMI cloud slicing reports a high NO2 VMR where the aircraft reported lightning NOx during the Deep Convection Clouds and Chemistry (DC3) campaign in 2012. We also provide a global seasonal climatology of free-tropospheric NO2 VMR in cloudy conditions. Enhanced NO2 in free troposphere commonly appears near polluted urban locations where NO2 produced in the boundary layer may be transported vertically out of the

  15. OZONE ABSORPTION IN RAW WATERS

    Directory of Open Access Journals (Sweden)

    LJILJANA TAKIĆ

    2008-03-01

    Full Text Available The ozone absorption in raw water entering the main ozonization step at the Belgrade drinking water supply plant was investigated in a continuous stirred tank reactor (CSTR. A slow chemical reaction rate of dissolved ozone and pollutants present in raw water have been experimentally determined. The modified Hatta number was defined and calculated as a criterion which determines whether and to which extent the reactions of ozone and pollutants influence the rate of the pure physical ozone absorption.

  16. Influence of the ozone profile above Madrid (Spain) on Brewer estimation of ozone air mass factor

    Energy Technology Data Exchange (ETDEWEB)

    Anton, M. [Univ. de Extremadura, Badajoz (Spain). Dept. de Fisica; Evora Univ. (PT). Goephysics Centre of Evora (CGE); Lopez, M.; Banon, M. [Agenica Estatal de Meteorologia (AEMET), Madrid (Spain); Costa, M.J.; Silva, A.M. [Evora Univ. (PT). Goephysics Centre of Evora (CGE); Evora Univ. (Portugal). Dept. of Physics; Serrano, A. [Univ. de Extremadura, Badajoz (Spain). Dept. de Fisica; Bortoli, D. [Evora Univ. (PT). Goephysics Centre of Evora (CGE); Vilaplana, J.M. [Instituto Nacional de Tecnica Aeroespacial (INTA), Huelva (Spain). Estacion de Sondeos Atmosferico ' ' El Arenosillo' '

    2009-07-01

    The methodology used by Brewer spectroradiometers to estimate the ozone column is based on differential absorption spectroscopy. This methodology employs the ozone air mass factor (AMF) to derive the total ozone column from the slant path ozone amount. For the calculating the ozone AMF, the Brewer algorithm assumes that the ozone layer is located at a fixed height of 22 km. However, for a real specific site the ozone presents a certain profile, which varies spatially and temporally depending on the latitude, altitude and dynamical conditions of the atmosphere above the site of measurements. In this sense, this work address the reliability of the mentioned assumption and analyses the influence of the ozone profiles measured above Madrid (Spain) in the ozone AMF calculations. The approximated ozone AMF used by the Brewer algorithm is compared with simulations obtained using the libRadtran radiative transfer model code. The results show an excellent agreement between the simulated and the approximated AMF values for solar zenith angle lower than 75 . In addition, the relative differences remain lower than 2% at 85 . These good results are mainly due to the fact that the altitude of the ozone layer assumed constant by the Brewer algorithm for all latitudes notably can be considered representative of the real profile of ozone above Madrid (average value of 21.7{+-}1.8 km). The operational ozone AMF calculations for Brewer instruments are limited, in general, to SZA below 80 . Extending the usable SZA range is especially relevant for Brewer instruments located at high mid-latitudes. (orig.)

  17. Observing lowermost tropospheric ozone pollution with a new multispectral synergic approach of IASI infrared and GOME-2 ultraviolet satellite measurements

    Science.gov (United States)

    Cuesta, Juan; Foret, Gilles; Dufour, Gaëlle; Eremenko, Maxim; Coman, Adriana; Gaubert, Benjamin; Beekmann, Matthias; Liu, Xiong; Cai, Zhaonan; Von Clarmann, Thomas; Spurr, Robert; Flaud, Jean-Marie

    2014-05-01

    Tropospheric ozone is currently one of the air pollutants posing greatest threats to human health and ecosystems. Monitoring ozone pollution at the regional, continental and global scale is a crucial societal issue. Only spaceborne remote sensing is capable of observing tropospheric ozone at such scales. The spatio-temporal coverage of new satellite-based instruments, such as IASI or GOME-2, offer a great potential for monitoring air quality by synergism with regional chemistry-transport models, for both inter-validation and full data assimilation. However, current spaceborne observations using single-band either UV or IR measurements show limited sensitivity to ozone in the atmospheric boundary layer, which is the major concern for air quality. Very recently, we have developed an innovative multispectral approach, so-called IASI+GOME-2, which combines IASI and GOME-2 observations, respectively in the IR and UV. This unique multispectral approach has allowed the observation of ozone plumes in the lowermost troposphere (LMT, below 3 km of altitude) over Europe, for the first time from space. Our first analyses are focused on typical ozone pollution events during the summer of 2009 over Europe. During these events, LMT ozone plumes at different regions are produced photo-chemically in the boundary layer, transported upwards to the free troposphere and also downwards from the stratosphere. We have analysed them using IASI+GOME-2 observations, in comparison with single-band methods (IASI, GOME-2 and OMI). Only IASI+GOME-2 depicts ozone plumes located below 3 km of altitude (both over land and ocean). Indeed, the multispectral sensitivity in the LMT is greater by 40% and it peaks at 2 to 2.5 km of altitude over land, thus at least 0.8 to 1 km below that for all single-band methods. Over Europe during the summer of 2009, IASI+GOME-2 shows 1% mean bias and 21% precision for direct comparisons with ozonesondes and also good agreement with CHIMERE model simulations

  18. Integrated Interpretation of Geophysical, Geotechnical, and Environmental Monitoring Data to Define Precursors for Landslide Activation

    Science.gov (United States)

    Uhlemann, S.; Chambers, J.; Merritt, A.; Wilkinson, P.; Meldrum, P.; Gunn, D.; Maurer, H.; Dixon, N.

    2014-12-01

    To develop a better understanding of the failure mechanisms leading to first time failure or reactivation of landslides, the British Geological Survey is operating an observatory on an active, shallow landslide in North Yorkshire, UK, which is a typical example of slope failure in Lias Group mudrocks. This group and the Whitby Mudstone Formation in particular, show one of the highest landslide densities in the UK. The observatory comprises geophysical (i.e., ERT and self-potential monitoring, P- and S-wave tomography), geotechnical (i.e. acoustic emission and inclinometer), and hydrological and environmental monitoring (i.e. weather station, water level, soil moisture, soil temperature), in addition to movement monitoring using real-time kinematic GPS. In this study we focus on the reactivation of the landslide at the end of 2012, after an exceptionally wet summer. We present an integrated interpretation of the different data streams. Results show that the two lobes (east and west), which form the main focus of the observatory, behave differently. While water levels, and hence pore pressures, in the eastern lobe are characterised by a continuous increase towards activation resulting in significant movement (i.e. metres), water levels in the western lobe are showing frequent drainage events and thus lower pore pressures and a lower level of movement (i.e. tens of centimetres). This is in agreement with data from the geoelectrical monitoring array. During the summer season, resistivities generally increase due to decreasing moisture levels. However, during the summer of 2012 this seasonal pattern was interrupted, with the reactivated lobe displaying strongly decreasing resistivities (i.e. increasing moisture levels). The self-potential and soil moisture data show clear indications of moisture accumulation prior to the reactivation, followed by continuous discharge towards the base of the slope. Using the different data streams, we present 3D volumetric images of

  19. Geophysical validation and long-term consistency between GOME-2/MetOp-A total ozone column and measurements from the sensors GOME/ERS-2, SCIAMACHY/ENVISAT and OMI/Aura

    Directory of Open Access Journals (Sweden)

    M. E. Koukouli

    2012-09-01

    Full Text Available The main aim of the paper is to assess the consistency of five years of Global Ozone Monitoring Experiment-2/Metop-A [GOME-2] total ozone columns and the long-term total ozone satellite monitoring database already in existence through an extensive inter-comparison and validation exercise using as reference Brewer and Dobson ground-based measurements. The behaviour of the GOME-2 measurements is being weighed against that of GOME (1995–2011, Ozone Monitoring Experiment [OMI] (since 2004 and the Scanning Imaging Absorption spectroMeter for Atmospheric CartograpHY [SCIAMACHY] (since 2002 total ozone column products. Over the background truth of the ground-based measurements, the total ozone columns are inter-evaluated using a suite of established validation techniques; the GOME-2 time series follow the same patterns as those observed by the other satellite sensors. In particular, on average, GOME-2 data underestimate GOME data by about 0.80%, and underestimate SCIAMACHY data by 0.37% with no seasonal dependence of the differences between GOME-2, GOME and SCIAMACHY. The latter is expected since the three datasets are based on similar DOAS algorithms. This underestimation of GOME-2 is within the uncertainty of the reference data used in the comparisons. Compared to the OMI sensor, on average GOME-2 data underestimate OMI_DOAS (collection 3 data by 1.28%, without any significant seasonal dependence of the differences between them. The lack of seasonality might be expected since both the GOME data processor [GDP] 4.4 and OMI_DOAS are DOAS-type algorithms and both consider the variability of the stratospheric temperatures in their retrievals. Compared to the OMI_TOMS (collection 3 data, no bias was found. We hence conclude that the GOME-2 total ozone columns are well suitable to continue the long-term global total ozone record with the accuracy needed for climate monitoring studies.

  20. Regionalization based on spatial and seasonal variation in ground-level ozone concentrations across China.

    Science.gov (United States)

    Cheng, Linjun; Wang, Shuai; Gong, Zhengyu; Li, Hong; Yang, Qi; Wang, Yeyao

    2018-05-01

    Owing to the vast territory of China and strong regional characteristic of ozone pollution, it's desirable for policy makers to have a targeted and prioritized regulation and ozone pollution control strategy in China based on scientific evidences. It's important to assess its current pollution status as well as spatial and temporal variation patterns across China. Recent advances of national monitoring networks provide an opportunity to insight the actions of ozone pollution. Here, we present rotated empirical orthogonal function (REOF) analysis that was used on studying the spatiotemporal characteristics of daily ozone concentrations. Based on results of REOF analysis in pollution seasons for 3years' observations, twelve regions with clear patterns were identified in China. The patterns of temporal variation of ozone in each region were separated well and different from each other, reflecting local meteorological, photochemical or pollution features. A rising trend in annual averaged Eight-hour Average Ozone Concentrations (O 3 -8hr) from 2014 to 2016 was observed for all regions, except for the Tibetan Plateau. The mean values of annual and 90 percentile concentrations for all 338 cities were 82.6±14.6 and 133.9±25.8μg/m 3 , respectively, in 2015. The regionalization results of ozone were found to be influenced greatly by terrain features, indicating significant terrain and landform effects on ozone spatial correlations. Among 12 regions, North China Plain, Huanghuai Plain, Central Yangtze River Plain, Pearl River Delta and Sichuan Basin were realized as priority regions for mitigation strategies, due to their higher ozone concentrations and dense population. Copyright © 2017. Published by Elsevier B.V.

  1. Investigations into regional ozone concentrations in the Bakken-Williston Basin using ARTEMIS, a mobile measurment platform.

    Science.gov (United States)

    Donohoue, D.; Jumes, D.; Jaglowski, J.

    2017-12-01

    During a campaign launched in August 2015, concentrations of ozone, nitrogen oxides, and weather conditions were measured throughout the Bakken-Williston Basin. The data was collected using a new in-situ monitoring system ARTEMIS (Atmospheric Research Trailer for Environmental Monitoring and Interactive Science). ARTEMIS is a self-sustaining trailer equipped with a solar panel and four 80 Ah batteries, which can power an instrumental suite. It provided a temporary sampling station which could be erected in five minutes. During this campaign we collected data for one hour at sites throughout North Dakota and Montana. Preliminary results from this data suggests that near active mining or methane flaring regions ozone concentrations appear to be elevated from the background.

  2. Intra-urban spatial variability of surface ozone in Riverside, CA: viability and validation of low-cost sensors

    Science.gov (United States)

    Sadighi, Kira; Coffey, Evan; Polidori, Andrea; Feenstra, Brandon; Lv, Qin; Henze, Daven K.; Hannigan, Michael

    2018-03-01

    Sensor networks are being more widely used to characterize and understand compounds in the atmosphere like ozone (O3). This study employs a measurement tool, called the U-Pod, constructed at the University of Colorado Boulder, to investigate spatial and temporal variability of O3 in a 200 km2 area of Riverside County near Los Angeles, California. This tool contains low-cost sensors to collect ambient data at non-permanent locations. The U-Pods were calibrated using a pre-deployment field calibration technique; all the U-Pods were collocated with regulatory monitors. After collocation, the U-Pods were deployed in the area mentioned. A subset of pods was deployed at two local regulatory air quality monitoring stations providing validation for the collocation calibration method. Field validation of sensor O3 measurements to minute-resolution reference observations resulted in R2 and root mean squared errors (RMSEs) of 0.95-0.97 and 4.4-5.9 ppbv, respectively. Using the deployment data, ozone concentrations were observed to vary on this small spatial scale. In the analysis based on hourly binned data, the median R2 values between all possible U-Pod pairs varied from 0.52 to 0.86 for ozone during the deployment. The medians of absolute differences were calculated between all possible pod pairs, 21 pairs total. The median values of those median absolute differences for each hour of the day varied between 2.2 and 9.3 ppbv for the ozone deployment. Since median differences between U-Pod concentrations during deployment are larger than the respective root mean square error values, we can conclude that there is spatial variability in this criteria pollutant across the study area. This is important because it means that citizens may be exposed to more, or less, ozone than they would assume based on current regulatory monitoring.

  3. Ozone as an air pollutant

    DEFF Research Database (Denmark)

    Berg, Rolf W.

    1996-01-01

    A Danish new book on ozone as an air pollutant has been reviewed. The Book is "Ozon som luftforurening" by Jes Fenger, Published by "Danmarks Miljøundersøgelser, 1995.......A Danish new book on ozone as an air pollutant has been reviewed. The Book is "Ozon som luftforurening" by Jes Fenger, Published by "Danmarks Miljøundersøgelser, 1995....

  4. Determination of the Optimum Ozone Product on the Plasma Ozonizer

    International Nuclear Information System (INIS)

    Agus Purwadi; Widdi Usada; Suryadi; Isyuniarto; Sri Sukmajaya

    2002-01-01

    An experiment of the optimum ozone product determination on the cylindrical plasma ozonizer has been done. The experiment is carried out by using alternating high voltage power supply, oscilloscope CS-1577 A, flow meter and spectronik-20 instrument for the absorbance solution samples which produced by varying the physics parameter values of the discharge alternating high voltage and velocity of oxygen gas input. The plasma ozonizer is made of cylinder stainless steel as the electrode and cylinder glass as the dielectric with 1.00 mm of the discharge gap and 7.225 mm 3 of the discharge tube volume. The experiment results shows that the optimum ozone product is 0.360 mg/s obtained at the the discharge of alternating high voltage of 25.50 kV, the frequency of 1.00 kHz and the rate of oxygen gas input of 1.00 lpm. (author)

  5. Tropospheric Ozone Pollution from Space: New Views from the TOMS (Total Ozone Mapping Spectrometer) Instrument

    Science.gov (United States)

    Thompson, Anne M.; Hudson, Robert D.; Frolov, Alexander D.; Witte, Jacquelyn C.; Kucsera, Tom L.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    New products from the TOMS (Total Ozone Mapping Spectrometer) >satellite instrument can resolve pollution events in tropical and mid-latitudes, Over the past several years, we have developed tropospheric ozone data sets by two methods. The modified-residual technique [Hudson and Thompson, 1998; Thompson and Hudson, 1999] uses v. 7 TOMS total ozone and is applicable to tropical regimes in which the wave-one pattern in total ozone is observed. The TOMSdirect method [Hudson et at., 2000] represents a new algorithm that uses TOMS radiances to extract tropospheric ozone in regions of constant stratospheric ozone and tropospheric ozone displaying high mixing ratios and variability characteristic of pollution, Absorbing aerosols (dust and smoke; Herman et at., 1997 Hsu et al., 1999), a standard TOMS product, provide transport and/or source marker information to interpret tropospheric ozone. For the Nimbus 7/TOMS observing period (1979-1992), modified-residual TTO (tropical tropospheric ozone) appears as two maps/month at I-degree latitude 2-degree longitude resolution at a homepage and digital data are available (20S to 20N) by ftp at http://metosrv2. umd.edu/tropo/ 14y_data.d. Preliminary modified-residual TTO data from the operational Earth-Probe/TOMS (1996- present) are posted in near-real-time at the same website. Analyses with the new tropospheric ozone and aerosol data are illustrated by the following (I)Signals in tropical tropospheric ozone column and smoke amount during ENSO (El Nino-Southern Oscillation) events, e.g. 1982-1983 and the intense ENSO induced biomass fires of 1997-1998 over the Indonesian region [Thompson et a[, 2000a, Thompson and Hudson, 1999]. (2) Trends in tropospheric ozone and smoke aerosols in various tropical regions (Atlantic, Pacific, Africa, Brazil). No significant trends were found for ozone from1980-1990 [Thompson and Hudson, 19991 although smoke aerosols increased during the period [Hsu et al.,1999]. (3) Temporal and spatial offsets

  6. Effect of Pre-ozonation on Haloacetic Acids Formation in Ganga River Water at Kanpur, India

    Science.gov (United States)

    Naladala, Nagasrinivasa Rao; Singh, Rambabu; Katiyar, Kumud Lata Devi; Bose, Purnendu; Dutta, Venkatesh

    2017-11-01

    Almost all natural water bodies which are considered to be sustainable sources of drinking water contain organic matter in dissolved form and pathogens. This dissolved organic matter and pathogens cannot be removed effectively through traditional filtering processes in drinking water treatment plants. Chlorination of such water for disinfection results in large amounts of disinfection by-products (DBPs), mainly trihalomethanes and haloacetic acids (HAAs), which showed many health effects like cancer and reproductive problems in lab animals and in human beings as well. Complete removal of dissolved organic carbon (DOC), which is a precursor compound for HAAs formation, is impossible from a practical point of view; hence, it will be better if DOC activity towards DBPs formation can be reduced via some process. The present article describes the process of pre-ozonating post-coagulated Ganga River water at Kanpur in a continuous flow mode and its effect on HAAs formation. Nearly 58% reduction in HAAs formation was observed during this study at higher doses of ozone.

  7. Influence of corona discharge on the ozone budget in the tropical free troposphere: a case study of deep convection during GABRIEL

    Science.gov (United States)

    Bozem, H.; Fischer, H.; Gurk, C.; Schiller, C. L.; Parchatka, U.; Koenigstedt, R.; Stickler, A.; Martinez, M.; Harder, H.; Kubistin, D.; Williams, J.; Eerdekens, G.; Lelieveld, J.

    2014-09-01

    Convective redistribution of ozone and its precursors between the boundary layer (BL) and the free troposphere (FT) influences photochemistry, in particular in the middle and upper troposphere (UT). We present a case study of convective transport during the GABRIEL campaign over the tropical rain forest in Suriname in October 2005. During one measurement flight the inflow and outflow regions of a cumulonimbus cloud (Cb) have been characterized. We identified a distinct layer between 9 and 11 km altitude with enhanced mixing ratios of CO, O3, HOx, acetone and acetonitrile. The elevated O3 contradicts the expectation that convective transport brings low-ozone air from the boundary layer to the outflow region. Entrainment of ozone-rich air is estimated to account for 62% (range: 33-91%) of the observed O3. Ozone is enhanced by only 5-6% by photochemical production in the outflow due to enhanced NO from lightning, based on model calculations using observations including the first reported HOx measurements over the tropical rainforest. The "excess" ozone in the outflow is most probably due to direct production by corona discharge associated with lightning. We deduce a production rate of 5.12 × 1028 molecules O3 flash-1 (range: 9.89 × 1026-9.82 × 1028 molecules O3 flash-1), which is at the upper limit of the range reported previously.

  8. Regional climate, local climate and ozone air pollution in Tours and Orleans cities

    International Nuclear Information System (INIS)

    Berthelot, M.

    2006-10-01

    The importance of the relations between climate and the air pollution justifies the interest related to the role of the urban heat island of heat with respect to the night persistence of ozone in urban environment. When the days are favourable with important ozone concentrations, the agglomerations of the area observe a dynamics day laborer of ozone different from that observed in rural environment. The study is undertaken on the towns of Turns and Orleans where the observations of Lig'Air revealed a night persistence of ozone whereas the concentrations drop more quickly in periphery. This phenomenon is remarkable during the little broken down anticyclonic days. The region region Centre is a ground of study privileged for ozone because of its situation in the south-west of the Island of France rich in precursors of ozone. When flow is of continental origin, the Centre area is found then under the influence of the Paris area. The investigation of a study of the air pollution must take into account the notes of the regional climate and local climate. Several preliminary studies must intervene to answer our principal problems. First of all a descriptive study of the regional climate is carried out with the participation of Meteo-France. The current absence of climatic atlas as well as the many disparities of the climate related to extended from the territory partly justify the interest of our study. The regional approach of the climate is also essential for the continuation of work on a finer scale on the agglomerations of Turns and Orleans in order to detect the urban heat island of heat there. Collaboration with Meteo-France and Lig'Air made it possible to establish a satisfying network of measurement making it possible to obtain notable thermal differences between the downtown area and the surrounding rural environment. The correlation between meteorology and the proven air pollution leads us to establish the climatology of ozone. Many are the studies having

  9. The Effect of Ozone Oxydans in Plastic of Polyethylene used for The Storage of Apple Manalagi (malus Sylvestris M)

    International Nuclear Information System (INIS)

    Isyuniarto; Agus-Purwadi

    2007-01-01

    The effect of ozone oxydans in plastic of polyethylene used for the storage of apple Manalagi (malus sylvestris M) have been done. Firstly, apple selected according to form and size then packed into storage of plastic polyethylene 3 and 5 mm in thickness and ozonization process is done from 0, 20, 40 and 60 seconds. The sample is monitored every 7, 14 and 21 days. Parameter perceived is texture of fruit, colour, smell and panelist option to this research. The result is thickly of plastic 3 mm and ozonization time 60 seconds. (author)

  10. The Unique OMI HCHO/NO2 Feature During the 2008 Beijing Summer Olympics: Implications for Ozone Production Sensitivity

    Science.gov (United States)

    Witte, J. C.; Duncan, B. N.; Douglass, A. R.; Kurosu, T. P.; Chance, K.; Retscher, C.

    2010-01-01

    In preparation of the Beijing Summer Olympic and Paralympics Games, strict controls were imposed between July and September 2008 on motor vehicle traffic and industrial emissions to improve air quality for the competitors. We assessed chemical sensitivity of ozone production to these controls using Ozone Monitoring Instrument (OMI) column measurements of formaldehyde (HCHO) and nitrogen dioxide (NO2), where their ratio serves as a proxy for the sensitivity. During the emission controls, HCHO/NO2 increased and indicated a NOx-limited regime, in contrast to the same period in the preceding three years when the ratio indicates volatile organic carbon (VOC)-limited and mixed NOx-VOC-limited regimes. After the emission controls were lifted, observed NO2 and HCHO/NO2 returned to their previous values. The 2005-2008 OMI record shows that this transition in regimes was unique as ozone production in Beijing was rarely NOx-limited. OMI measured summertime increases in HCHO of around 13% in 2008 compared to prior years, the same time period during which MODIS vegetation indices increased. The OMI HCHO increase may be due to higher biogenic emissions of HCHO precursors, associated with Beijing's greening initiative for the Olympics. However, NO2 and HCHO were also found to be well-correlated during the summer months. This indicates an anthropogenic VOC contribution from vehicle emissions to OMI HCHO and is a plausible explanation for the relative HCHO minimum observed in August 2008, concurrent with a minimum in traffic emissions. We calculated positive trends in 2005-2008 OMI HCHO and NO2 of about +1 x 10(exp 14) Molec/ square M-2 and +3 x 10(exp 13) molec CM-2 per month, respectively. The positive trend in NO2 may be an indicator of increasing vehicular traffic since 2005, while the positive trend in HCHO may be due to a combined increase in anthropogenic and biogenic emissions since 2005.

  11. Assessing the risk of foliar injury from ozone on vegetation in parks in the U.S. National Park Service's Vital Signs Network

    International Nuclear Information System (INIS)

    Kohut, Robert

    2007-01-01

    The risk of ozone injury to plants was assessed in support of the National Park Service's Vital Signs Monitoring Network program. The assessment examined bioindicator species, evaluated levels of ozone exposure, and investigated soil moisture conditions during periods of exposure for a 5-year period in each park. The assessment assigned each park a risk rating of high, moderate, or low. For the 244 parks for which assessments were conducted, the risk of foliar injury was high in 65 parks, moderate in 46 parks, and low in 131 parks. Among the well-known parks with a high risk of ozone injury are Gettysburg, Valley Forge, Delaware Water Gap, Cape Cod, Fire Island, Antietam, Harpers Ferry, Manassas, Wolf Trap Farm Park, Mammoth Cave, Shiloh, Sleeping Bear Dunes, Great Smoky Mountains, Joshua Tree, Sequoia and Kings Canyon, and Yosemite. - An assessment of the risk of foliar ozone injury on plants was conducted for 269 parks in support of the U.S. National Park Service's Vital Signs Monitoring Network Program

  12. The Effect of Elevated Ozone Concentrations with Varying Shading on Dry Matter Loss in a Winter Wheat-Producing Region in China.

    Science.gov (United States)

    Xu, Jingxin; Zheng, Youfei; He, Yuhong; Wu, Rongjun; Mai, Boru; Kang, Hanqing

    2016-01-01

    Surface-level ozone pollution causes crop production loss by directly reducing healthy green leaf area available for carbon fixation. Ozone and its precursors also affect crop photosynthesis indirectly by decreasing solar irradiance. Pollutants are reported to have become even more severe in Eastern China over the last ten years. In this study, we investigated the effect of a combination of elevated ozone concentrations and reduced solar irradiance on a popular winter wheat Yangmai13 (Triticum aestivum L.) at field and regional levels in China. Winter wheat was grown in artificial shading and open-top-chamber environments. Treatment 1 (T1, i.e., 60% shading with an enhanced ozone of 100±9 ppb), Treatment 2 (T2, i.e., 20% shading with an enhanced ozone of 100±9 ppb), and Control Check Treatment (CK, i.e., no shading with an enhanced ozone of 100±9 ppb), with two plots under each, were established to investigate the response of winter wheat under elevated ozone concentrations and varying solar irradiance. At the field level, linear temporal relationships between dry matter loss and cumulative stomatal ozone uptake were first established through a parameterized stomatal-flux model. At the regional level, ozone concentrations and meteorological variables, including solar irradiance, were simulated using the WRF-CMAQ model (i.e., a meteorology and air quality modeling system). These variables were then used to estimate cumulative stomatal ozone uptake for the four major winter wheat-growing provinces. The regional-level cumulative ozone uptake was then used as the independent variable in field data-based regression models to predict dry matter loss over space and time. Field-level results showed that over 85% (T1: R(2) = 0.85 & T2: R(2) = 0.89) of variation in dry matter loss was explained by cumulative ozone uptake. Dry matter was reduced by 3.8% in T1 and 2.2% in T2 for each mmol O3·m(-2) of cumulative ozone uptake. At the regional level, dry matter loss in winter

  13. The Effect of Elevated Ozone Concentrations with Varying Shading on Dry Matter Loss in a Winter Wheat-Producing Region in China.

    Directory of Open Access Journals (Sweden)

    Jingxin Xu

    Full Text Available Surface-level ozone pollution causes crop production loss by directly reducing healthy green leaf area available for carbon fixation. Ozone and its precursors also affect crop photosynthesis indirectly by decreasing solar irradiance. Pollutants are reported to have become even more severe in Eastern China over the last ten years. In this study, we investigated the effect of a combination of elevated ozone concentrations and reduced solar irradiance on a popular winter wheat Yangmai13 (Triticum aestivum L. at field and regional levels in China. Winter wheat was grown in artificial shading and open-top-chamber environments. Treatment 1 (T1, i.e., 60% shading with an enhanced ozone of 100±9 ppb, Treatment 2 (T2, i.e., 20% shading with an enhanced ozone of 100±9 ppb, and Control Check Treatment (CK, i.e., no shading with an enhanced ozone of 100±9 ppb, with two plots under each, were established to investigate the response of winter wheat under elevated ozone concentrations and varying solar irradiance. At the field level, linear temporal relationships between dry matter loss and cumulative stomatal ozone uptake were first established through a parameterized stomatal-flux model. At the regional level, ozone concentrations and meteorological variables, including solar irradiance, were simulated using the WRF-CMAQ model (i.e., a meteorology and air quality modeling system. These variables were then used to estimate cumulative stomatal ozone uptake for the four major winter wheat-growing provinces. The regional-level cumulative ozone uptake was then used as the independent variable in field data-based regression models to predict dry matter loss over space and time. Field-level results showed that over 85% (T1: R(2 = 0.85 & T2: R(2 = 0.89 of variation in dry matter loss was explained by cumulative ozone uptake. Dry matter was reduced by 3.8% in T1 and 2.2% in T2 for each mmol O3·m(-2 of cumulative ozone uptake. At the regional level, dry matter

  14. Quantifying the contributions to stratospheric ozone changes from ozone depleting substances and greenhouse gases

    Directory of Open Access Journals (Sweden)

    D. A. Plummer

    2010-09-01

    Full Text Available A state-of-the-art chemistry climate model coupled to a three-dimensional ocean model is used to produce three experiments, all seamlessly covering the period 1950–2100, forced by different combinations of long-lived Greenhouse Gases (GHGs and Ozone Depleting Substances (ODSs. The experiments are designed to quantify the separate effects of GHGs and ODSs on the evolution of ozone, as well as the extent to which these effects are independent of each other, by alternately holding one set of these two forcings constant in combination with a third experiment where both ODSs and GHGs vary. We estimate that up to the year 2000 the net decrease in the column amount of ozone above 20 hPa is approximately 75% of the decrease that can be attributed to ODSs due to the offsetting effects of cooling by increased CO2. Over the 21st century, as ODSs decrease, continued cooling from CO2 is projected to account for more than 50% of the projected increase in ozone above 20 hPa. Changes in ozone below 20 hPa show a redistribution of ozone from tropical to extra-tropical latitudes with an increase in the Brewer-Dobson circulation. In addition to a latitudinal redistribution of ozone, we find that the globally averaged column amount of ozone below 20 hPa decreases over the 21st century, which significantly mitigates the effect of upper stratospheric cooling on total column ozone. Analysis by linear regression shows that the recovery of ozone from the effects of ODSs generally follows the decline in reactive chlorine and bromine levels, with the exception of the lower polar stratosphere where recovery of ozone in the second half of the 21st century is slower than would be indicated by the decline in reactive chlorine and bromine concentrations. These results also reveal the degree to which GHG-related effects mute the chemical effects of N2O on ozone in the standard future scenario used for the WMO Ozone Assessment. Increases in the

  15. Inhibition of trihalomethane formation in city water by radiation-ozone treatment and rapid composting of radiation disinfected sewage sludge

    International Nuclear Information System (INIS)

    Takehisa, M.; Arai, H.; Arai, M.

    1985-01-01

    Humic acid and Fulvic acid in natural water are precursors of carcinogenic THM which is formed during chlorine disinfection in city water processing. The radiation-oxidation process in the presence of ozone is effective to remove the precursors. The THM formation was reduced more than the decrease in TOC by the combination treatment. This is mainly due to a change in the chemical structure of the oxidation products. A composting of radiation disinfected sludge cake for agricultural reuse could be achieved within 3 days primary fermentation in a sewage plant. The rapid fermentation with use of radiation is effective to scale down of a fermentor of composting plant and the process reduces a health risk from the workers as well as final users. (author)

  16. Inhibition of trihalomethane formation in city water by radiation-ozone treatment and rapid composting of radiation disinfected sewage sludge

    Energy Technology Data Exchange (ETDEWEB)

    Takehisa, M; Arai, H; Arai, M

    1985-01-01

    Humic acid and Fulvic acid in natural water are precursors of carcinogenic THM which is formed during chlorine disinfection in city water processing. The radiation-oxidation process in the presence of ozone is effective to remove the precursors. The THM formation was reduced more than the decrease in TOC by the combination treatment. This is mainly due to a change in the chemical structure of the oxidation products. A composting of radiation disinfected sludge cake for agricultural reuse could be achieved within 3 days primary fermentation in a sewage plant. The rapid fermentation with use of radiation is effective to scale down a fermentor of a composting plant and the process reduces health risk for the workers as well as final users.

  17. New-Generation NASA Aura Ozone Monitoring Instrument (OMI) Volcanic SO2 Dataset: Algorithm Description, Initial Results, and Continuation with the Suomi-NPP Ozone Mapping and Profiler Suite (OMPS)

    Science.gov (United States)

    Li, Can; Krotkov, Nickolay A.; Carn, Simon; Zhang, Yan; Spurr, Robert J. D.; Joiner, Joanna

    2017-01-01

    Since the fall of 2004, the Ozone Monitoring Instrument (OMI) has been providing global monitoring of volcanic SO2 emissions, helping to understand their climate impacts and to mitigate aviation hazards. Here we introduce a new-generation OMI volcanic SO2 dataset based on a principal component analysis (PCA) retrieval technique. To reduce retrieval noise and artifacts as seen in the current operational linear fit (LF) algorithm, the new algorithm, OMSO2VOLCANO, uses characteristic features extracted directly from OMI radiances in the spectral fitting, thereby helping to minimize interferences from various geophysical processes (e.g., O3 absorption) and measurement details (e.g., wavelength shift). To solve the problem of low bias for large SO2 total columns in the LF product, the OMSO2VOLCANO algorithm employs a table lookup approach to estimate SO2 Jacobians (i.e., the instrument sensitivity to a perturbation in the SO2 column amount) and iteratively adjusts the spectral fitting window to exclude shorter wavelengths where the SO2 absorption signals are saturated. To first order, the effects of clouds and aerosols are accounted for using a simple Lambertian equivalent reflectivity approach. As with the LF algorithm, OMSO2VOLCANO provides total column retrievals based on a set of predefined SO2 profiles from the lower troposphere to the lower stratosphere, including a new profile peaked at 13 km for plumes in the upper troposphere. Examples given in this study indicate that the new dataset shows significant improvement over the LF product, with at least 50% reduction in retrieval noise over the remote Pacific. For large eruptions such as Kasatochi in 2008 (approximately 1700 kt total SO2/ and Sierra Negra in 2005 (greater than 1100DU maximum SO2), OMSO2VOLCANO generally agrees well with other algorithms that also utilize the full spectral content of satellite measurements, while the LF algorithm tends to underestimate SO2. We also demonstrate that, despite the

  18. Tropospheric Ozone: a Menace for Crops and Natural Vegetation in Greece

    Directory of Open Access Journals (Sweden)

    Costas Saitanis

    Full Text Available Based on instrumental monitoring (AOT40s and phytodetection (with Bel-W3 and KK6/5 tobacco cultivars data we evaluated ambient ozone phytotoxicity in Greece. In the greater region of Mesogia-Attica, during the summer of 2000, the year before the new airport Eleftherios Venizelos (March 2001 began operating in this region, the AOT40s (ppb*h were 16,325 over 110 days at Spata; 18,646 over 113 days at Markopoulo; 8,093 over 22 days at Artemis and 16,679 over 121 days in Athens. The Bel- W3 and KK6/5 plants were extensively injured at all places with the greatest injury occurring at Artemis. During the same summer, ozone was also monitored in three rural areas of Corinth, at the Astronomical Observatory of Krionerion, Bogdani Hill and Kiato; The highest average daily AOT40 (192 ppb*h was observed in Krionerio, and it was almost equal to that occurred in Athens (193 ppb*h. Bel-W3 and KK6/5 plants placed at 11 rural areas in Corinth showed extended injury. The following year (2001, high injury was observed on other sets of bioindicator plants exposed in a network of 28 locations throughout the greater area of Volos and Pelion Mountain. Symptoms were more severe at Mortias, Xinovrisi, Tsagarada, Makrinitsa and Chania. The AOT40 (May-July was 11,391 and 10,351 ppb*hours for 2001 and 2002 respectively. Severe ozone-like symptoms have also been observed on field-cultivated grape vines, onion and watermelon plants. Synoptically, our investigations suggest that ozone occurs in the Greek mainland at levels that are potentially phytotoxic for sensitive crop species and for sensitive natural vegetation species including forest trees.

  19. Ozone health effects

    International Nuclear Information System (INIS)

    Easterly, C.

    1994-01-01

    Ozone is a principal component of photochemical air pollution endogenous to numerous metropolitan areas. It is primarily formed by the oxidation of NOx in the presence of sunlight and reactive organic compounds. Ozone is a highly active oxidizing agent capable of causing injury to the lung. Lung injury may take the form of irritant effects on the respiratory tract that impair pulmonary function and result in subjective symptoms of respiratory discomfort. These symptoms include, but are not limited to, cough and shortness of breath, and they can limit exercise performance. The effects of ozone observed in humans have been primarily limited to alterations in respiratory function, and a range of respiratory physiological parameters have been measured as a function of ozone exposure in adults and children. These affects have been observed under widely varying (clinical experimental and environmental settings) conditions

  20. N-Nitrosodimethylamine (NDMA) and its precursors in water and wastewater: A review on formation and removal.

    Science.gov (United States)

    Sgroi, Massimiliano; Vagliasindi, Federico G A; Snyder, Shane A; Roccaro, Paolo

    2018-01-01

    This review summarizes major findings over the last decade related to N-Nitrosodimethylamine (NDMA) in water and wastewater. In particular, the review is focused on the removal of NDMA and of its precursors by conventional and advanced water and wastewater treatment processes. New information regarding formation mechanisms and precursors are discussed as well. NDMA precursors are generally of anthropogenic origin and their main source in water have been recognized to be wastewater discharges. Chloramination is the most common process that results in formation of NDMA during water and wastewater treatment. However, ozonation of wastewater or highly contaminated surface water can also generate significant levels of NDMA. Thus, NDMA formation control and remediation has become of increasing interest, particularly during treatment of wastewater-impacted water and during potable reuse application. NDMA formation has also been associated with the use of quaternary amine-based coagulants and anion exchange resins. UV photolysis with UV fluence far higher than typical disinfection doses is generally considered the most efficient technology for NDMA mitigation. However, recent studies on the optimization of biological processes offer a potentially lower-energy solution. Options for NDMA control include attenuation of precursor materials through physical removal, biological treatment, and/or deactivation by application of oxidants. Nevertheless, NDMA precursor identification and removal can be challenging and additional research and optimization is needed. As municipal wastewater becomes increasingly used as a source water for drinking, NDMA formation and mitigation strategies will become increasingly more important. The following review provides a summary of the most recent information available. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. A surface plasmon resonance immunosensor for detecting a dioxin precursor using a gold binding polypeptide

    DEFF Research Database (Denmark)

    Soh, N; Tokuda, T.; Watanabe, T.

    2003-01-01

    A surface plasmon resonance (SPR) based biosensor was developed for monitoring 2,4-dichlorophenol, a known dioxin precursor, using an indirect competitive immunoassay. The SPR sensor was fabricated by immobilizing a gold-thin layer on the surface of an SPR sensor chip with an anti-(2,4-dichloroph......A surface plasmon resonance (SPR) based biosensor was developed for monitoring 2,4-dichlorophenol, a known dioxin precursor, using an indirect competitive immunoassay. The SPR sensor was fabricated by immobilizing a gold-thin layer on the surface of an SPR sensor chip with an anti-(2...

  2. Technical Report 14-11 Overview of Danish Contributions to Monitoring of SLCPs in the Arctic

    DEFF Research Database (Denmark)

    Korsholm, Ulrik Smith; Krogh Andersen, Katrine; Christensen, Tina

    2014-01-01

    In the Tromsø Declaration (2009) the Arctic Council noted the role that shorter-lived climate forcers such as black carbon, methane and tropospheric ozone precursors may play in Arctic climate change, and recognized that reductions of emissions have the potential to slow the rate of Arctic snow...

  3. Advanced treatment of biotreated textile industry wastewater with ozone, virgin/ozonated granular activated carbon and their combination.

    Science.gov (United States)

    Arslan-Alaton, Idil; Seremet, Ozden

    2004-01-01

    Biotreated textile wastewater (CODo = 248 mg L(-1); TOCo = 58 mg L(-1); A620 = 0.007 cm(-1); A525 = 0.181 cm(-1); A436 = 0.198 cm(-1)) was subjected to advanced treatment with ozonation, granular activated carbon (GAC) adsorption in serial and simultaneous applications. Experiments were conducted to investigate the effects of applied ozone dose, ozone absorption rate, specific ozone absorption efficiency, GAC dose, and reaction pH on the treatment performance of the selected tertiary treatment scheme. In separate experiments, the impact of virgin GAC ozonation on its adsorptive capacity for biotreated and biotreated + ozonated textile effluent was also investigated. Ozonation appeared to be more effective for decolorization (kd = 0.15 min(-1) at pH = 3), whereas GAC adsorption yielded higher COD removal rates (54% at pH = 3). It was also found that GAC addition (4 g/L) at pH = 7 and 9 enhanced the COD abatement rate of the ozonation process significantly and that the sequential application of ozonation (at pH = 3-11, 675 mg L(-1) O3) followed by GAC adsorption (at pH = 3-7, 10 g L(-1) GAC) resulted in the highest treatment performances both in terms of color and COD reduction. Simultaneous application of GAC and ozone at acidic and alkaline pH seriously inhibited COD abatement rates as a consequence of competitive adsorption and partial oxidation of textile components and GAC. It could also be established that ozone absorption efficiency decreased after color removal was complete. Ozonation of biotreated textile wastewater with 113 mg L(-1) ozone resulted in an appreciable enhancement of GAC adsorptive capacity in terms of residual color removal. Ozonation of GAC at relatively low doses (= 10.8 mg/g GAC) did not improve its overall adsorption capacity.

  4. Degradation of p-nitrotoluene in aqueous solution by ozonation combined with sonolysis

    International Nuclear Information System (INIS)

    Song Shuang; Xia Min; He Zhiqiao; Ying Haiping; Lue Bosheng; Chen Jianmeng

    2007-01-01

    p-Nitrotoluene (PNT) is a nitroaromatic compound that is hazardous to humans and is a suspected hormone disrupter. The degradation of PNT in aqueous solution by ozonation (O 3 ) combined with sonolysis (US) was investigated in laboratory-scale experiments in which pH, initial concentration of PNT, O 3 dose and temperature were varied. The degradation of PNT followed pseudo-first-order kinetics, and degradation products were monitored during the process. The maximum degradation was observed at pH 10.0. As the initial concentration of PNT decreased, the degradation rate increased. Both temperature and ozone dose had a positive effect on the degradation of PNT. Of the total organic carbon (TOC) reduction, 8, 68, and 85% were observed with US, O 3 , and a combination of US and O 3 after reaction for 90 min, respectively, proving that ozonation combined with sonolysis for removal of TOC is more efficient than ozonation alone or ultrasonic irradiation alone. Major by-products, including p-cresol, 4-hydroxybenzaldehyde, 4-hydroxybenzoic acid, 4-(oxomethylene) cyclohexa-2,5-dien-1-one, but-2-enedioic acid, and acetic acid were detected by gas chromatography coupled with mass spectrometry

  5. Optical remote measurement of ozone in cirrus clouds; Optische Fernmessung von Ozon in Zirruswolken

    Energy Technology Data Exchange (ETDEWEB)

    Reichardt, J. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Physikalische und Chemische Analytik

    1998-12-31

    The subject of this thesis is theoretical and experimental investigations into the simultaneous optical remote measurement of atmospheric ozone concentration and particle properties. A lidar system was developed that combines the Raman-lidar and the polarization-lidar with the Raman-DIAL technique. An error analysis is given for ozone measurements in clouds. It turns out that the wavelength dependencies of photon multiple scattering and of the particle extinction coefficient necessitate a correction of the measured ozone concentration. To quantify the cloud influence, model calculations based on particle size distributions of spheres are carried out. The most important experimental result of this thesis is the measured evidence of pronounced minima in the ozone distribution in a humid upper troposphere shortly before and during cirrus observation. Good correlation between ozone-depleted altitude ranges and ice clouds is found. This finding is in contrast to ozone profiles measured in a dry and cloud-free troposphere. (orig.) 151 refs.

  6. Study of ozone gas formed in the industrial radiation process with cobalt-60 and its impact on the environment

    International Nuclear Information System (INIS)

    Uzueli, Daniel Henrique

    2013-01-01

    The radiation processing is present in various products such as foods, medical disposable, electrical cables, gems, among others. This process aims to improve the properties, sterilize or sanitize irradiated products. In industrial irradiators facilities, electromagnetic radiation (gamma and X-rays) or electrons before they interact with the products in processing, there are a layer of air. To interact with this air layer, it causes radiolytic effects on the molecules present in the ambient atmosphere, and the main interaction are with the oxygen molecules that have their bonds broken, separating them into two highly reactive atoms that recombine with the other molecule of oxygen to form ozone gas. In this work it was studied the formation, decay and dispersion of ozone in industrial gamma irradiators facilities that use cobalt-60 as a source of radiation. The monitoring of ozone concentration was performed by optical absorption method in a commercial monitor. (author)

  7. Experimental study of ozone synthesis

    International Nuclear Information System (INIS)

    Garamoon, A A; Elakshar, F F; Nossair, A M; Kotp, E F

    2002-01-01

    A silent discharge ozonizer has been constructed with a design that enables the study of ozone concentration behaviour as a function of different parameters when oxygen used as a working gas. The behaviour of ozone concentration as a function of discharge current density has four characteristic regions. The concentration is enhanced by more than threefold whenever gas pressure is reduced by a factor of two. The flow rate of the working gas is a more effective parameter on ozone concentration than the gas pressure. When the flow rate is kept constant, and the pressure is decreased by 100%, the ozone concentration increases by only 10%. On the other hand, when the flow rate is decreased by 13%, the ozone concentration increases by 200%, whenever the gas pressure is kept constant. The concentration is nearly doubled when the gap space is increased by four times under the same conditions. The length of the discharge region, the thickness and the dielectric constant of the insulating materials are found to have a considerable effect on the generated ozone concentration. Also, the ozone concentration is ten times less when air is used instead of oxygen as a working gas. A maximum efficiency of 185 g/kWh, is obtained for the present system

  8. Ozone kinetics in low-pressure discharges

    Science.gov (United States)

    Guerra, Vasco; Marinov, Daniil; Guaitella, Olivier; Rousseau, Antoine

    2012-10-01

    Ozone kinetics is quite well established at atmospheric pressure, due to the importance of ozone in atmospheric chemistry and to the development of industrial ozone reactors. However, as the pressure is decreased and the dominant three-body reactions lose importance, the main mechanisms involved in the creation and destruction of ozone are still surrounded by important uncertainties. In this work we develop a self-consistent model for a pulsed discharge and its afterglow operating in a Pyrex reactor with inner radius 1 cm, at pressures in the range 1-5 Torr and discharge currents of 40-120 mA. The model couples the electron Boltzmann equation with a system of equations for the time evolution of the heavy particles. The calculations are compared with time-dependent measurements of ozone and atomic oxygen. Parametric studies are performed in order to clarify the role of vibrationally excited ozone in the overall kinetics and to establish the conditions where ozone production on the surface may become important. It is shown that vibrationally excited ozone does play a significant role, by increasing the time constants of ozone formation. Moreover, an upper limit for the ozone formation at the wall in these conditions is set at 10(-4).

  9. Physicochemical patterns of ozone absorption by wood

    Science.gov (United States)

    Mamleeva, N. A.; Lunin, V. V.

    2016-11-01

    Results from studying aspen and pine wood ozonation are presented. The effect the concentration of ozone, the reagent residence time, and the content of water in a sample of wood has on ozone consumption rate and ozone demand are analyzed. The residence time is shown to determine the degree of ozone conversion degree and the depth of substrate destruction. The main patterns of ozone absorption by wood with different moisture content are found. Ways of optimizing the ozonation of plant biomass are outlined.

  10. Influence of corona discharge on the ozone budget in the tropical free troposphere: a case study of deep convection during GABRIEL

    Science.gov (United States)

    Bozem, H.; Fischer, H.; Gurk, C.; Schiller, C. L.; Parchatka, U.; Koenigstedt, R.; Stickler, A.; Martinez, M.; Harder, H.; Kubistin, D.; Williams, J.; Eerdekens, G.; Lelieveld, J.

    2014-02-01

    Convective redistribution of ozone and its precursors between the boundary layer (BL) and the free troposphere (FT) influences photochemistry, in particular that of the middle and upper troposphere (UT). We present a case study of convective transport during the GABRIEL campaign over the tropical rain forest in Suriname in October 2005. During a measurement flight on 12 October the inflow and outflow regions of a cumulonimbus cloud (Cb) have been characterized, providing evidence of convective transport. We identified a distinct layer between 9 and 11 km altitude with enhanced mixing ratios of CO, O3, HOx, acetone and acetonitrile. The elevated O3 contradicts the expectation that convective transport brings low ozone air from the boundary layer to the outflow region. The enhanced mixing ratio of ozone in the outflow was mainly of dynamical origin. Entrainment of ozone rich air at the outflow level into the convective outflow accounts for 62% (range: 33-91%) of the observed O3. Ozone is enhanced by only 5-6% by photochemical production in the outflow due to enhanced NO from lightning, based on steady state model calculations, using in-situ observations including the first reported HOx measurements over the tropical rainforest. The "excess" ozone in the outflow is most probably due to direct production by corona discharge associated with lightning. We deduce a production rate of 5.12 × 1028 molecules O3 flash-1 (range: 9.89 × 1026-9.82 × 1028 molecules O3 flash-1), which is at the upper limit of the range of the values reported previously.

  11. Understanding Animal Detection of Precursor Earthquake Sounds.

    Science.gov (United States)

    Garstang, Michael; Kelley, Michael C

    2017-08-31

    We use recent research to provide an explanation of how animals might detect earthquakes before they occur. While the intrinsic value of such warnings is immense, we show that the complexity of the process may result in inconsistent responses of animals to the possible precursor signal. Using the results of our research, we describe a logical but complex sequence of geophysical events triggered by precursor earthquake crustal movements that ultimately result in a sound signal detectable by animals. The sound heard by animals occurs only when metal or other surfaces (glass) respond to vibrations produced by electric currents induced by distortions of the earth's electric fields caused by the crustal movements. A combination of existing measurement systems combined with more careful monitoring of animal response could nevertheless be of value, particularly in remote locations.

  12. Influence of isoprene chemical mechanism on modelled changes in tropospheric ozone due to climate and land use over the 21st century

    Science.gov (United States)

    Squire, O. J.; Archibald, A. T.; Griffiths, P. T.; Jenkin, M. E.; Smith, D.; Pyle, J. A.

    2015-05-01

    Isoprene is a~precursor to tropospheric ozone, a key pollutant and greenhouse gas. Anthropogenic activity over the coming century is likely to cause large changes in atmospheric CO2 levels, climate and land use, all of which will alter the global vegetation distribution leading to changes in isoprene emissions. Previous studies have used global chemistry-climate models to assess how possible changes in climate and land use could affect isoprene emissions and hence tropospheric ozone. The chemistry of isoprene oxidation, which can alter the concentration of ozone, is highly complex, therefore it must be parameterised in these models. In this work, we compare the effect of four different reduced isoprene chemical mechanisms, all currently used in Earth system models, on tropospheric ozone. Using a box model we compare ozone in these reduced schemes to that in a more explicit scheme (the Master Chemical Mechanism) over a range of NOx and isoprene emissions, through the use of O3 isopleths. We find that there is some variability, especially at high isoprene emissions, caused by differences in isoprene-derived NOx reservoir species. A global model is then used to examine how the different reduced schemes respond to potential future changes in climate, isoprene emissions, anthropogenic emissions and land use change. We find that, particularly in isoprene-rich regions, the response of the schemes varies considerably. The wide-ranging response is due to differences in the model descriptions of the peroxy radical chemistry, particularly their relative rates of reaction towards NO, leading to ozone formation, or HO2, leading to termination. Also important is the yield of isoprene nitrates and peroxyacyl nitrate precursors from isoprene oxidation. Those schemes that produce less of these NOx reservoir species, tend to produce more ozone locally and less away from the source region. We also note changes in other key oxidants such as NO3 and OH (due to the inclusion of

  13. Stratospheric ozone intrusion events and their impacts on tropospheric ozone in the Southern Hemisphere

    Directory of Open Access Journals (Sweden)

    J. W. Greenslade

    2017-09-01

    Full Text Available Stratosphere-to-troposphere transport (STT provides an important natural source of ozone to the upper troposphere, but the characteristics of STT events in the Southern Hemisphere extratropics and their contribution to the regional tropospheric ozone budget remain poorly constrained. Here, we develop a quantitative method to identify STT events from ozonesonde profiles. Using this method we estimate the seasonality of STT events and quantify the ozone transported across the tropopause over Davis (69° S, 2006–2013, Macquarie Island (54° S, 2004–2013, and Melbourne (38° S, 2004–2013. STT seasonality is determined by two distinct methods: a Fourier bandpass filter of the vertical ozone profile and an analysis of the Brunt–Väisälä frequency. Using a bandpass filter on 7–9 years of ozone profiles from each site provides clear detection of STT events, with maximum occurrences during summer and minimum during winter for all three sites. The majority of tropospheric ozone enhancements owing to STT events occur within 2.5 and 3 km of the tropopause at Davis and Macquarie Island respectively. Events are more spread out at Melbourne, occurring frequently up to 6 km from the tropopause. The mean fraction of total tropospheric ozone attributed to STT during STT events is  ∼ 1. 0–3. 5 % at each site; however, during individual events, over 10 % of tropospheric ozone may be directly transported from the stratosphere. The cause of STTs is determined to be largely due to synoptic low-pressure frontal systems, determined using coincident ERA-Interim reanalysis meteorological data. Ozone enhancements can also be caused by biomass burning plumes transported from Africa and South America, which are apparent during austral winter and spring and are determined using satellite measurements of CO. To provide regional context for the ozonesonde observations, we use the GEOS-Chem chemical transport model, which is too coarsely

  14. First Directly Retrieved Global Distribution of Tropospheric Column Ozone from GOME: Comparison with the GEOS-CHEM Model

    Science.gov (United States)

    Liu, Xiong; Chance, Kelly; Sioris, Christopher E.; Kurosu, Thomas P.; Spurr, Robert J. D.; Martin, Randall V.; Fu, Tzung-May; Logan, Jennifer A.; Jacob, Daniel J.; Palmer, Paul I.; hide

    2006-01-01

    We present the first directly retrieved global distribution of tropospheric column ozone from Global Ozone Monitoring Experiment (GOME) ultraviolet measurements during December 1996 to November 1997. The retrievals clearly show signals due to convection, biomass burning, stratospheric influence, pollution, and transport. They are capable of capturing the spatiotemporal evolution of tropospheric column ozone in response to regional or short time-scale events such as the 1997-1998 El Nino event and a 10-20 DU change within a few days. The global distribution of tropospheric column ozone displays the well-known wave-1 pattern in the tropics, nearly zonal bands of enhanced tropospheric column ozone of 36-48 DU at 20degS-30degS during the austral spring and at 25degN-45degN during the boreal spring and summer, low tropospheric column ozone of 33 DU at some northern high-latitudes during the spring. Simulation from a chemical transport model corroborates most of the above structures, with small biases of <+/-5 DU and consistent seasonal cycles in most regions, especially in the southern hemisphere. However, significant positive biases of 5-20 DU occur in some northern tropical and subtropical regions such as the Middle East during summer. Comparison of GOME with monthly-averaged Measurement of Ozone and Water Vapor by Airbus in-service Aircraft (MOZAIC) tropospheric column ozone for these regions usually shows good consistency within 1 a standard deviations and retrieval uncertainties. Some biases can be accounted for by inadequate sensitivity to lower tropospheric ozone, the different spatiotemporal sampling and the spatiotemporal variations in tropospheric column ozone.

  15. Measurements of total and tropospheric ozone from IASI: comparison with correlative satellite, ground-based and ozonesonde observations

    Directory of Open Access Journals (Sweden)

    A. Boynard

    2009-08-01

    Full Text Available In this paper, we present measurements of total and tropospheric ozone, retrieved from infrared radiance spectra recorded by the Infrared Atmospheric Sounding Interferometer (IASI, which was launched on board the MetOp-A European satellite in October 2006. We compare IASI total ozone columns to Global Ozone Monitoring Experiment-2 (GOME-2 observations and ground-based measurements from the Dobson and Brewer network for one full year of observations (2008. The IASI total ozone columns are shown to be in good agreement with both GOME-2 and ground-based data, with correlation coefficients of about 0.9 and 0.85, respectively. On average, IASI ozone retrievals exhibit a positive bias of about 9 DU (3.3% compared to both GOME-2 and ground-based measurements. In addition to total ozone columns, the good spectral resolution of IASI enables the retrieval of tropospheric ozone concentrations. Comparisons of IASI tropospheric columns to 490 collocated ozone soundings available from several stations around the globe have been performed for the period of June 2007–August 2008. IASI tropospheric ozone columns compare well with sonde observations, with correlation coefficients of 0.95 and 0.77 for the [surface–6 km] and [surface–12 km] partial columns, respectively. IASI retrievals tend to overestimate the tropospheric ozone columns in comparison with ozonesonde measurements. Positive average biases of 0.15 DU (1.2% and 3 DU (11% are found for the [surface–6 km] and for the [surface–12 km] partial columns respectively.

  16. Stratospheric ozone chemistry in the Antarctic: what determines the lowest ozone values reached and their recovery?

    Directory of Open Access Journals (Sweden)

    J.-U. Grooß

    2011-12-01

    Full Text Available Balloon-borne observations of ozone from the South Pole Station have been reported to reach ozone mixing ratios below the detection limit of about 10 ppbv at the 70 hPa level by late September. After reaching a minimum, ozone mixing ratios increase to above 1 ppmv on the 70 hPa level by late December. While the basic mechanisms causing the ozone hole have been known for more than 20 yr, the detailed chemical processes determining how low the local concentration can fall, and how it recovers from the minimum have not been explored so far. Both of these aspects are investigated here by analysing results from the Chemical Lagrangian Model of the Stratosphere (CLaMS. As ozone falls below about 0.5 ppmv, a balance is maintained by gas phase production of both HCl and HOCl followed by heterogeneous reaction between these two compounds in these simulations. Thereafter, a very rapid, irreversible chlorine deactivation into HCl can occur, either when ozone drops to values low enough for gas phase HCl production to exceed chlorine activation processes or when temperatures increase above the polar stratospheric cloud (PSC threshold. As a consequence, the timing and mixing ratio of the minimum ozone depends sensitively on model parameters, including the ozone initialisation. The subsequent ozone increase between October and December is linked mainly to photochemical ozone production, caused by oxygen photolysis and by the oxidation of carbon monoxide and methane.

  17. Combined anaerobic–ozonation process for treatment of textile wastewater: Removal of acute toxicity and mutagenicity

    Energy Technology Data Exchange (ETDEWEB)

    Punzi, Marisa, E-mail: marisa.punzi@biotek.lu.se [Department of Biotechnology, Lund University, P.O. Box 124, SE-221 00 Lund (Sweden); Nilsson, Filip [Water and Environmental Engineering at the Department of Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund (Sweden); Anbalagan, Anbarasan [Department of Biotechnology, Lund University, P.O. Box 124, SE-221 00 Lund (Sweden); Svensson, Britt-Marie [School of Education and Environment, Kristianstad University, SE-291 88 Kristianstad (Sweden); Jönsson, Karin [Water and Environmental Engineering at the Department of Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund (Sweden); Mattiasson, Bo; Jonstrup, Maria [Department of Biotechnology, Lund University, P.O. Box 124, SE-221 00 Lund (Sweden)

    2015-07-15

    Highlights: • COD and UV absorbance were effectively reduced. • The treated effluents were non-toxic to Artemia salina and Vibrio fischeri. • The real textile wastewater was mutagenic. • Mutagenicity persisted after bio treatment and even more after a short ozonation. • Higher ozone doses completely remove mutagenicity. - Abstract: A novel set up composed of an anaerobic biofilm reactor followed by ozonation was used for treatment of artificial and real textile effluents containing azo dyes. The biological treatment efficiently removed chemical oxygen demand and color. Ozonation further reduced the organic content of the effluents and was very important for the degradation of aromatic compounds, as shown by the reduction of UV absorbance. The acute toxicity toward Vibrio fischeri and the shrimp Artemia salina increased after the biological treatment. No toxicity was detected after ozonation with the exception of the synthetic effluent containing the highest concentration, 1 g/l, of the azo dye Remazol Red. Both untreated and biologically treated textile effluents were found to have mutagenic effects. The mutagenicity increased even further after 1 min of ozonation. No mutagenicity was however detected in the effluents subjected to longer exposure to ozone. The results of this study suggest that the use of ozonation as short post-treatment after a biological process can be beneficial for the degradation of recalcitrant compounds and the removal of toxicity of textile wastewater. However, monitoring of toxicity and especially mutagenicity is crucial and should always be used to assess the success of a treatment strategy.

  18. Enhanced WWTP effluent organic matter removal in hybrid ozonation-coagulation (HOC) process catalyzed by Al-based coagulant

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Xin [School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an, Shaanxi Province, 710055 (China); Jin, Pengkang, E-mail: pkjin@hotmail.com [School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an, Shaanxi Province, 710055 (China); Hou, Rui [School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an, Shaanxi Province, 710055 (China); Yang, Lei [Department of Materials Science and Engineering, Monash University, Clayton, VIC, 3800 (Australia); Wang, Xiaochang C., E-mail: xcwang@xauat.edu.cn [School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an, Shaanxi Province, 710055 (China)

    2017-04-05

    Highlights: • A novel HOC process was firstly put forward to apply in wastewater reclamation. • Interactions between ozone and Al-based coagulants was found in the HOC process. • Ozonation can be catalyzed and enhanced by Al-based coagulants in the HOC process. • HOC process showed better organics removal than pre-ozonation-coagulation process. - Abstract: A novel hybrid ozonation-coagulation (HOC) process was developed for application in wastewater reclamation. In this process, ozonation and coagulation occurred simultaneously within a single unit. Compared with the conventional pre-ozonation-coagulation process, the HOC process exhibited much better performance in removing dissolved organic matters. In particular, the maximal organic matters removal efficiency was obtained at the ozone dosage of 1 mgO{sub 3}/mg DOC at each pH value (pH 5, 7 and 9). In order to interpret the mechanism of the HOC process, ozone decomposition was monitored. The results indicated that ozone decomposed much faster in the HOC process. Moreover, by using the reagent of O{sub 3}-resistant hydroxyl radical (·OH) probe compound, para-chlorobenzoic acid (pCBA), and electron paramagnetic resonance (EPR) analysis, it was observed that the HOC process generated higher content of ·OH compared with pre-ozonation process. This indicates that the ·OH oxidation reaction as the key step can be catalyzed and enhanced by Al-based coagulants and their hydrolyzed products in this developed process. Thus, based on the catalytic effects of Al-based coagulants on ozonation, the HOC process provides a promising alternative to the conventional technology for wastewater reclamation in terms of higher efficiency.

  19. Ozone Therapy in Dentistry

    Science.gov (United States)

    Domb, William C

    2014-01-01

    Summary The 21st century dental practice is quite dynamic. New treatment protocols and new materials are being developed at a rapid pace. Ozone dental therapy falls into the category of new treatment protocols in dentistry, yet ozone is not new at all. Ozone therapy is already a major treatment modality in Europe, South America and a number of other countries. What is provided here will not be an exhaustive scientific treatise so much as a brief general introduction into what dentists are now doing with ozone therapies and the numerous oral/systemic links that make this subject so important for physicians so that, ultimately, they may serve their patients more effectively and productively. PMID:25363268

  20. Observations of Radical Precursors during TexAQS II: Findings and Implications

    Science.gov (United States)

    Olaguer, E. P.; Lefer, B. L.; Rappenglueck, B.; Pinto, J. P.

    2009-12-01

    The Texas Environmental Research Consortium (TERC) sponsored and helped organize significant components of the Second Texas Air Quality Study (TexAQS II). Some of the TERC-sponsored experiments, most notably those associated with the TexAQS II Radical and Aerosol Measurement Project (TRAMP) sited on top of the Moody Tower at the University of Houston, found evidence for the importance of short-lived radical sources such as formaldehyde (HCHO) and nitrous acid (HONO) in increasing ozone productivity. During TRAMP, daytime HCHO pulses as large as 32 ppb were observed and attributed to industrial activities upwind in the Houston Ship Channel (HSC), and HCHO peaks as large as 52 ppb were detected by in-situ surface monitors in the HSC. In addition, an instrumented Piper Aztec aircraft observed plumes of apparent primary formaldehyde in flares from petrochemical facilities in the HSC. In one such combustion plume, depleted of ozone by large NOx emissions, the Piper Aztec measured an HCHO-to-CO ratio three times that of mobile sources. HCHO from uncounted primary sources or ozonolysis of underestimated olefin emissions could significantly increase ozone productivity in Houston beyond previous expectations. Simulations with the CAMx model show that additional emissions of HCHO from industrial flares can increase peak ozone in Houston by up to 30 ppb, depending on conditions in the planetary boundary layer. Other findings from TexAQS II include significant concentrations of HONO throughout the day, well in excess of current air quality model predictions, with large nocturnal vertical gradients indicating a surface or near-surface source of HONO, and large concentrations of night-time radicals (~30 ppt HO2). Additional HONO sources could increase daytime ozone by more than 10 ppb. Improving the representation of primary and secondary HCHO and HONO in air quality models could enhance the effectiveness of simulated control strategies, and thus make ozone attainment