Within season and carry-over effects following exposure of grassland species mixtures to increasing background ozone

Energy Technology Data Exchange (ETDEWEB)

Hayes, Felicity, E-mail: fhay@ceh.ac.uk [Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW (United Kingdom); Mills, Gina; Harmens, Harry; Wyness, Kirsten [Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW (United Kingdom)

2011-10-15

Few studies have investigated effects of increased background ozone in the absence of episodic peaks, despite a predicted increase throughout the northern hemisphere over the coming decades. In this study Leontodon hispidus was grown with Anthoxanthum odoratum or Dactylis glomerata and exposed in the UK to one of eight background ozone concentrations for 20 weeks in solardomes. Seasonal mean ozone concentrations ranged from 21.4 to 102.5 ppb. Ozone-induced senescence of L. hispidus was enhanced when grown with the more open canopy of A. odoratum compared to the denser growing D. glomerata. There was increased cover with increasing ozone exposure for both A. odoratum and D. glomerata, which resulted in an increase in the grass:Leontodon cover ratio in both community types. Carry-over effects of the ozone exposure were observed, including delayed winter die-back of L. hispidus and acceleration in the progression from flowers to seed-heads in the year following ozone exposure. - Highlights: > Increased background ozone concentrations increased the grass:forb cover ratio. > Competing grass species influenced ozone enhanced senescence of Leontodon hispidus. > Ozone delayed winter die-back of leaves of L. hispidus. > Flowering was accelerated for L. hispidus in the year following ozone exposure. - Increased background ozone enhanced leaf senescence and caused carry-over effects including reduced winter die-back and an acceleration in flowering the next year.

Effect of pulsed corona discharge voltage and feed gas flow rate on dissolved ozone concentration

International Nuclear Information System (INIS)

Prasetyaningrum, A.; Ratnawati,; Jos, B.

2015-01-01

Ozonization is one of the methods extensively used for water purification and degradation of organic materials. Ozone (O 3 ) is recognized as a powerful oxidizing agent. Due to its strong oxidability and better environmental friendless, ozone increasing being used in domestic and industrial applications. Current technology in ozone production utilizes several techniques (corona discharge, ultra violet radiation and electrolysis). This experiment aimed to evaluating effect of voltage and gas flow rate on ozone production with corona discharge. The system consists of two net-type stainless steel electrode placed in a dielectric barrier. Three pulsed voltage (20, 30, 40 KV) and flow rate (5, 10, 15 L/min) were prepare for operation variable at high frequency (3.7 kHz) with AC pulsed power supply. The dissolved ozone concentration depends on the applied high-voltage level, gas flow rate and the discharge exposure duration. The ozone concentration increases with decreasing gas flow rate. Dissolved ozone concentrations greater than 200 ppm can be obtained with a minimum voltage 40 kV

Effect of pulsed corona discharge voltage and feed gas flow rate on dissolved ozone concentration

Science.gov (United States)

Prasetyaningrum, A.; Ratnawati, Jos, B.

2015-12-01

Ozonization is one of the methods extensively used for water purification and degradation of organic materials. Ozone (O3) is recognized as a powerful oxidizing agent. Due to its strong oxidability and better environmental friendless, ozone increasing being used in domestic and industrial applications. Current technology in ozone production utilizes several techniques (corona discharge, ultra violet radiation and electrolysis). This experiment aimed to evaluating effect of voltage and gas flow rate on ozone production with corona discharge. The system consists of two net-type stainless steel electrode placed in a dielectric barrier. Three pulsed voltage (20, 30, 40 KV) and flow rate (5, 10, 15 L/min) were prepare for operation variable at high frequency (3.7 kHz) with AC pulsed power supply. The dissolved ozone concentration depends on the applied high-voltage level, gas flow rate and the discharge exposure duration. The ozone concentration increases with decreasing gas flow rate. Dissolved ozone concentrations greater than 200 ppm can be obtained with a minimum voltage 40 kV.

Effect of pulsed corona discharge voltage and feed gas flow rate on dissolved ozone concentration

Energy Technology Data Exchange (ETDEWEB)

Prasetyaningrum, A., E-mail: ajiprasetyaningrum@gmail.com; Ratnawati,; Jos, B. [Department of Chemical Engineering, Faculty of Engineering, Diponegoro University Jl. Prof. H. Soedarto Tembalang, Semarang, Central Java, Indonesia, 50276 (Indonesia)

2015-12-29

Ozonization is one of the methods extensively used for water purification and degradation of organic materials. Ozone (O{sub 3}) is recognized as a powerful oxidizing agent. Due to its strong oxidability and better environmental friendless, ozone increasing being used in domestic and industrial applications. Current technology in ozone production utilizes several techniques (corona discharge, ultra violet radiation and electrolysis). This experiment aimed to evaluating effect of voltage and gas flow rate on ozone production with corona discharge. The system consists of two net-type stainless steel electrode placed in a dielectric barrier. Three pulsed voltage (20, 30, 40 KV) and flow rate (5, 10, 15 L/min) were prepare for operation variable at high frequency (3.7 kHz) with AC pulsed power supply. The dissolved ozone concentration depends on the applied high-voltage level, gas flow rate and the discharge exposure duration. The ozone concentration increases with decreasing gas flow rate. Dissolved ozone concentrations greater than 200 ppm can be obtained with a minimum voltage 40 kV.

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

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

Effects of plug-in hybrid electric vehicles on ozone concentrations in Colorado.

Science.gov (United States)

Brinkman, Gregory L; Denholm, Paul; Hannigan, Michael P; Milford, Jana B

2010-08-15

This study explores how ozone concentrations in the Denver, CO area might have been different if plug-in hybrid electric vehicles (PHEVs) had replaced light duty gasoline vehicles in summer 2006. A unit commitment and dispatch model was used to estimate the charging patterns of PHEVs and dispatch power plants to meet electricity demand. Emission changes were estimated based on gasoline displacement and the emission characteristics of the power plants providing additional electricity. The Comprehensive Air Quality Model with extensions (CAMx) was used to simulate the effects of these emissions changes on ozone concentrations. Natural gas units provided most of the electricity used for charging PHEVs in the scenarios considered. With 100% PHEV penetration, nitrogen oxide (NO(x)) emissions were reduced by 27 tons per day (tpd) from a fleet of 1.7 million vehicles and were increased by 3 tpd from power plants; VOC emissions were reduced by 57 tpd. These emission changes reduced modeled peak 8-h average ozone concentrations by approximately 2-3 ppb on most days. Ozone concentration increases were modeled for small areas near central Denver. Future research is needed to forecast when significant PHEV penetration may occur and to anticipate characteristics of the corresponding power plant and vehicle fleets.

Effect of ozone concentration on silicon surface passivation by atomic layer deposited Al2O3

International Nuclear Information System (INIS)

Gastrow, Guillaume von; Li, Shuo; Putkonen, Matti; Laitinen, Mikko; Sajavaara, Timo; Savin, Hele

2015-01-01

Highlights: • The ALD Al 2 O 3 passivation quality can be controlled by the ozone concentration. • Ozone concentration affects the Si/Al 2 O 3 interface charge and defect density. • A surface recombination velocity of 7 cm/s is reached combining ozone and water ALD. • Carbon and hydrogen concentrations correlate with the surface passivation quality. - Abstract: We study the impact of ozone-based Al 2 O 3 Atomic Layer Deposition (ALD) on the surface passivation quality of crystalline silicon. We show that the passivation quality strongly depends on the ozone concentration: the higher ozone concentration results in lower interface defect density and thereby improved passivation. In contrast to previous studies, our results reveal that too high interface hydrogen content can be detrimental to the passivation. The interface hydrogen concentration can be optimized by the ozone-based process; however, the use of pure ozone increases the harmful carbon concentration in the film. Here we demonstrate that low carbon and optimal hydrogen concentration can be achieved by a single process combining the water- and ozone-based reactions. This process results in an interface defect density of 2 × 10 11 eV −1 cm −2 , and maximum surface recombination velocities of 7.1 cm/s and 10 cm/s, after annealing and after an additional firing at 800 °C, respectively. In addition, our results suggest that the effective oxide charge density can be optimized in a simple way by varying the ozone concentration and by injecting water to the ozone process.

Steady-state ozone concentration in radiation induced noble gas-oxygen discharges

International Nuclear Information System (INIS)

Elsayed-Ali, H.E.; Miley, G.H.

1985-01-01

Measurements of steady-state ozone concentrations in continuous radiation induced noble gas-O 2 and noble gas-O 2 -SF 6 mixtures has been accomplished. The discharges were created through the bombardment of the gases with energetic particles from the boron-10 (n,α) lithium-7 nuclear reaction. Three noble gases were studied, He, Ne, and Ar at partial pressures of few hundred Torr. The dose rates studied were in the order of 10 15 eV.cm -3 .s -1 . The experimental apparatus and proceedure were previously described. The experimentally observed stead-state ozone concentrations in noble gas-O 2 discharges were about an order of magnitude lower than that observed for oxygen radiolysis at similar dose rates. These results were physically explained by an enhanced role of negative ionic reactions with ozone causing its destruction. In noble gas-O 2 -SF 6 mixtures, the steady-state ozone concentrations were found to be significantly higher (3-6 times) than that without the SF 6 addition. This observation was contrary to only a small increase observed after SF 6 addition to a few hundred Torr oxygen and is explained by an enhanced rate of electron dissociative attachment of ozone in noble gas-O 2 discharges

Effect of Nearby Forest Fires on Ground Level Ozone Concentrations in Santiago, Chile

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María A. Rubio

2015-12-01

Full Text Available On 4 and 8 January 2014, at the height of the austral summer, intense wildfires in forests and dry pastures occurred in the Melipilla sector, located about 70 km to the southwest of Santiago, the Chilean capital, affecting more than 6 million inhabitants. Low level winds transported the forest fire plume towards Santiago causing a striking decrease in visibility and a marked increase in the concentration of both primary (PM10 and CO and secondary (Ozone pollutants in the urban atmosphere. In particular, ozone maximum concentrations in the Santiago basin reached hourly averages well above 80 ppb, the national air quality standard. This ozone increase took place at the three sampling sites considered in the present study. These large values can be explained in terms of high NOx concentrations and NO2/NO ratios in biomass burning emissions.

Asymmetric correlations in the ozone concentration dynamics of the Mexico City Metropolitan Area

Science.gov (United States)

Meraz, M.; Alvarez-Ramirez, J.; Echeverria, J. C.

2017-04-01

Mexico City is a megalopolis with severe pollution problems caused by vehicles and industrial activity. This condition imposes important risks to human health and economic activity. Based on hourly-sampled data during the last decade, in a recent work (Meraz et al., 2015) we showed that the pollutant dynamics in Mexico City exhibits long-term and scale-dependent persistence effects resulting from the combination of pollutants generation by vehicles and removal by advection mechanisms. In this work, we analyzed the dynamics of ozone, a key component reflecting the degree of atmospheric contamination, to determine if its long-term correlations are asymmetric in relation to the actual concentration trend (increasing or decreasing). The analysis is conducted with detrended fluctuation analysis. The results showed that the average ozone dynamics is uncorrelated when the concentration is increasing. In contrast, the ozone dynamics shows long-term anti-persistence effects when the concentration is decreasing.

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

Steady-state ozone concentrations in radiation induced noble gas-oxygen discharges

International Nuclear Information System (INIS)

Elsayed-Ali, H.E.; Miley, G.H.

1985-01-01

Measurements of steady-state ozone concentrations in continuous radiation induced noble gas-O/sub 2/ and noble gas-o/sub 2/-SF/sub 6/ mixtures has been accomplished. The discharges were created through the bombardment of the gases with energetic particles from the boron-10 (n,α) lithium-7 nuclear reaction. Three noble gases were studied, He, Ne, and Ar at partial pressures of few hundred Torr. The dose rates studied were in the order of 10/sup 15/ eV . cm/sup -3/ . s/sup -1/. The experimental apparatus and procedure were previously described. The experimentally observed steady-state ozone concentrations in noble gas-O/sub 2/ discharges were about an order of magnitude lower than that observed for oxygen radiolysis at similar dose rates. These results were physically explained by an enhanced role of negative ionic reactions with ozone causing its destruction. In noble gas-O/sub 2/-SF/sub 6/ mixtures, the steady-state ozone concentrations were found to be significantly higher (3-6 times) than that without the SF/sub 6/ addition. This observation was contrary to only a small increase observed after SF/sub 6/ addition to a few hundred Torr oxygen and is explained by an enhanced rate of electron dissociative attachment of ozone in noble gas-O/sub 2/ discharges

Projections of summertime ozone concentration over East Asia under multiple IPCC SRES emission scenarios

Science.gov (United States)

Lee, Jae-Bum; Cha, Jun-Seok; Hong, Sung-Chul; Choi, Jin-Young; Myoung, Ji-Su; Park, Rokjin J.; Woo, Jung-Hun; Ho, Changhoi; Han, Jin-Seok; Song, Chang-Keun

2015-04-01

We have developed the Integrated Climate and Air Quality Modeling System (ICAMS) through the one-way nesting of global-regional models to examine the changes in the surface ozone concentrations over East Asia under future climate scenarios. Model simulations have been conducted for the present period of 1996-2005 to evaluate the performance of ICAMS. The simulated surface ozone concentrations reproduced the observed monthly mean concentrations at sites in East Asia with high R2 values (0.4-0.9), indicating a successful simulation to capture both spatial and temporal variability. We then performed several model simulations with the six IPCC SRES scenarios (A2, A1B, A1FI, A1T, B1, and B2) for the next three periods, 2016-2025 (the 2020s), 2046-2055 (the 2050s), and 2091-2100 (the 2090s). The model results show that the projected changes of the annual daily mean maximum eight-hour (DM8H) surface ozone concentrations in summertime for East Asia are in the range of 2-8 ppb, -3 to 8 ppb, and -7 to 9 ppb for the 2020s, the 2050s, and the 2090s, respectively, and are primarily determined based on the emission changes of NOx and NMVOC. The maximum increases in the annual DM8H surface ozone and high-ozone events occur in the 2020s for all scenarios except for A2, implying that the air quality over East Asia is likely to get worse in the near future period (the 2020s) than in the far future periods (the 2050s and the 2090s). The changes in the future environment based on IPCC SRES scenarios would also influence the change in the occurrences of high-concentrations events more greatly than that of the annual DM8H surface ozone concentrations. Sensitivity simulations show that the emissions increase is the key factor in determining future regional surface ozone concentrations in the case of a developing country, China, whereas a developed country, Japan would be influenced more greatly by effects of the regional climate change than the increase in emissions.

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

Fine root dynamics of mature European beech (Fagus sylvatica L.) as influenced by elevated ozone concentrations

International Nuclear Information System (INIS)

Mainiero, Raphael; Kazda, Marian; Haeberle, Karl-Heinz; Nikolova, Petia Simeonova; Matyssek, Rainer

2009-01-01

Fine root dynamics (diameter < 1 mm) in mature Fagus sylvatica, with the canopies exposed to ambient or twice-ambient ozone concentrations, were investigated throughout 2004. The focus was on the seasonal timing and extent of fine root dynamics (growth, mortality) in relation to the soil environment (water content, temperature). Under ambient ozone concentrations, a significant relationship was found between fine root turnover and soil environmental changes indicating accelerated fine root turnover under favourable soil conditions. In contrast, under elevated ozone, this relationship vanished as the result of an altered temporal pattern of fine root growth. Fine root survival and turnover rate did not differ significantly between the different ozone regimes, although a delay in current-year fine root shedding was found under the elevated ozone concentrations. The data indicate that increasing tropospheric ozone levels can alter the timing of fine root turnover in mature F. sylvatica but do not affect the turnover rate. - Doubling of ozone concentrations in mature European beech affected the seasonal timing of fine root turnover rather than the turnover rate.

Ozone sonde cell current measurements and implications for observations of near-zero ozone concentrations in the tropical upper troposphere

Directory of Open Access Journals (Sweden)

H. Vömel

2010-04-01

Full Text Available Laboratory measurements of the Electrochemical Concentration Cell (ECC ozone sonde cell current using ozone free air as well as defined amounts of ozone reveal that background current measurements during sonde preparation are neither constant as a function of time, nor constant as a function of ozone concentration. Using a background current, measured at a defined timed after exposure to high ozone may often overestimate the real background, leading to artificially low ozone concentrations in the upper tropical troposphere, and may frequently lead to operator dependent uncertainties. Based on these laboratory measurements an improved cell current to partial pressure conversion is proposed, which removes operator dependent variability in the background reading and possible artifacts in this measurement. Data from the Central Equatorial Pacific Experiment (CEPEX have been reprocessed using the improved background treatment based on these laboratory measurements. In the reprocessed data set near-zero ozone events no longer occur. At Samoa, Fiji, Tahiti, and San Cristóbal, nearly all near-zero ozone concentrations occur in soundings with larger background currents. To a large extent, these events are no longer observed in the reprocessed data set using the improved background treatment.

Elevated atmospheric ozone increases concentration of insecticidal Bacillus thuringiensis (Bt) Cry1Ac protein in Bt Brassica napus and reduces feeding of a Bt target herbivore on the non-transgenic parent

International Nuclear Information System (INIS)

Himanen, Sari J.; Nerg, Anne-Marja; Nissinen, Anne; Stewart, C. Neal; Poppy, Guy M.; Holopainen, Jarmo K.

2009-01-01

Sustained cultivation of Bacillus thuringiensis (Bt) transgenic crops requires stable transgene expression under variable abiotic conditions. We studied the interactions of Bt toxin production and chronic ozone exposure in Bt cry1Ac-transgenic oilseed rape and found that the insect resistance trait is robust under ozone elevations. Bt Cry1Ac concentrations were higher in the leaves of Bt oilseed rape grown under elevated ozone compared to control treatment, measured either per leaf fresh weight or per total soluble protein of leaves. The mean relative growth rate of a Bt target herbivore, Plutella xylostella L. larvae was negative on Bt plants in all ozone treatments. On the non-transgenic plants, larval feeding damage was reduced under elevated ozone. Our results indicate the need for monitoring fluctuations in Bt toxin concentrations to reveal the potential of ozone exposure for altering dosing of Bt proteins to target and non-target herbivores in field environments experiencing increasing ozone pollution. - Elevated atmospheric ozone can induce fluctuations in insecticidal protein concentrations in transgenic plants

Elevated atmospheric ozone increases concentration of insecticidal Bacillus thuringiensis (Bt) Cry1Ac protein in Bt Brassica napus and reduces feeding of a Bt target herbivore on the non-transgenic parent

Energy Technology Data Exchange (ETDEWEB)

Himanen, Sari J. [University of Kuopio, Department of Environmental Science, P.O. Box 1627, FIN-70211 Kuopio (Finland)], E-mail: sari.himanen@uku.fi; Nerg, Anne-Marja [University of Kuopio, Department of Environmental Science, P.O. Box 1627, FIN-70211 Kuopio (Finland); Nissinen, Anne [University of Kuopio, Department of Environmental Science, P.O. Box 1627, FIN-70211 Kuopio (Finland); MTT Agrifood Research Finland, Plant Protection, FIN-31600 Jokioinen (Finland); Stewart, C. Neal [University of Tennessee, Department of Plant Sciences, Knoxville, TN 37996-4561 (United States); Poppy, Guy M. [University of Southampton, School of Biological Sciences, Southampton SO16 7PX (United Kingdom); Holopainen, Jarmo K. [University of Kuopio, Department of Environmental Science, P.O. Box 1627, FIN-70211 Kuopio (Finland)

2009-01-15

Sustained cultivation of Bacillus thuringiensis (Bt) transgenic crops requires stable transgene expression under variable abiotic conditions. We studied the interactions of Bt toxin production and chronic ozone exposure in Bt cry1Ac-transgenic oilseed rape and found that the insect resistance trait is robust under ozone elevations. Bt Cry1Ac concentrations were higher in the leaves of Bt oilseed rape grown under elevated ozone compared to control treatment, measured either per leaf fresh weight or per total soluble protein of leaves. The mean relative growth rate of a Bt target herbivore, Plutella xylostella L. larvae was negative on Bt plants in all ozone treatments. On the non-transgenic plants, larval feeding damage was reduced under elevated ozone. Our results indicate the need for monitoring fluctuations in Bt toxin concentrations to reveal the potential of ozone exposure for altering dosing of Bt proteins to target and non-target herbivores in field environments experiencing increasing ozone pollution. - Elevated atmospheric ozone can induce fluctuations in insecticidal protein concentrations in transgenic plants.

Detection of Changes in Ground-Level Ozone Concentrations via Entropy

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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.

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.

The relationship between some meteorological parameters and the tropospheric concentrations of ozone in the urban area of Belgrade

Directory of Open Access Journals (Sweden)

DRAGAN M. MARKOVIC

2005-12-01

Full Text Available During the period between June and December 2002, the concentrations of ozone in the air at 4 measuring sites in Belgrade were measured. The measuring periods varied from 10 days to several weeks. Themaximalmeasured daily concentrations of ozone ranged from 19 ppbv (23 December 2002 to 118 ppbv (23 June 2002. Ozone concentrations higher than, or equal to 90 ppbv were registered at threemeasuring sites. It was shown that at measuring sites characterized as urban, maximal O3 concentrations equal to, or higher than 90 ppbv occurred at high temperatures (higher than 30 oC and low wind speeds (mostly from the north. The measured ozone concentrations mostly showed characteristics usual for a daily photochemical ozone cycle, excluding the specificities influenced by the measuring site itself. Ozone transport was recorded at increased wind speeds, primarily from south-easterly directions. On the basis of he correlations between ozone concentration and the corresponding meteorological parameters, a validation of the measuring sites was performed from the aspect of their representativeness for the measurements.

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

Although certain factors controlling plant emission rates of volatile organic compounds (VOCs) are reasonably well understood, the influence of elevated ozone concentrations as abiotic stress is mostly unknown. Therefore, we studied the effects of ozone concentrations on seasonal biogenic volatile organic compound (BVOC) emissions by different Mediterranean plant species in open top chambers (OTC). Three ozone treatments were established: filtered air (F), non-filtered air (NF), and fumigated air (NF+) adding 40 nl l{sup -1} of ozone over NF. We studied the response of VOC emission in saplings of four Mediterranean woody plant species and subspecies: Ceratonia siliqua L., Olea europaea L., Quercus ilex spp. ilex L., and Quercus ilex spp. rotundifolia L. as representative of natural Mediterranean vegetation. No visible symptoms were detected on the leaves. No significant effect was found on net photosynthetic rates or stomatal conductance except for an increase in net photosynthetic rates in Quercus ilex ilex in spring and summer and an overall slight increase in Quercus ilex rotundifolia. Emissions of the total VOCs from Ceratonia siliqua in summer, and from Olea europaea and Quercus ilex rotundifolia in spring increased in ozone fumigated OTC in comparison with F or NF OTC. Decreased emissions were found in Quercus ilex rotundifolia in summer. There were no significant differences between ozone fumigation treatments for the other plant species and seasons. When considering particular VOCs, the results were also variable among species and time of the year. While {alpha}-pinene emissions decreased with ozone fumigation in Olea europaea, {alpha}-pinene and limonene emissions increased in Quercus ilex ilex. The responses of these particular VOCs did not always match the responses of total VOCs. In spite of this strong variability, when considering overall annual data for all species and seasons, there were increased net photosynthetic rates (37%) and limonene (95

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.

Although certain factors controlling plant emission rates of volatile organic compounds (VOCs) are reasonably well understood, the influence of elevated ozone concentrations as abiotic stress is mostly unknown. Therefore, we studied the effects of ozone concentrations on seasonal biogenic volatile organic compound (BVOC) emissions by different Mediterranean plant species in open top chambers (OTC). Three ozone treatments were established: filtered air (F), non-filtered air (NF), and fumigated air (NF+) adding 40 nl l -1 of ozone over NF. We studied the response of VOC emission in saplings of four Mediterranean woody plant species and subspecies: Ceratonia siliqua L., Olea europaea L., Quercus ilex spp. ilex L., and Quercus ilex spp. rotundifolia L. as representative of natural Mediterranean vegetation. No visible symptoms were detected on the leaves. No significant effect was found on net photosynthetic rates or stomatal conductance except for an increase in net photosynthetic rates in Quercus ilex ilex in spring and summer and an overall slight increase in Quercus ilex rotundifolia. Emissions of the total VOCs from Ceratonia siliqua in summer, and from Olea europaea and Quercus ilex rotundifolia in spring increased in ozone fumigated OTC in comparison with F or NF OTC. Decreased emissions were found in Quercus ilex rotundifolia in summer. There were no significant differences between ozone fumigation treatments for the other plant species and seasons. When considering particular VOCs, the results were also variable among species and time of the year. While α-pinene emissions decreased with ozone fumigation in Olea europaea, α-pinene and limonene emissions increased in Quercus ilex ilex. The responses of these particular VOCs did not always match the responses of total VOCs. In spite of this strong variability, when considering overall annual data for all species and seasons, there were increased net photosynthetic rates (37%) and limonene (95%) and total VOC (45

Evidence of a 50-year increase in tropospheric ozone in Upper Bavaria

Directory of Open Access Journals (Sweden)

M. Schmidt

Full Text Available In a series of ozone-sonde soundings at the Hohenpeißenberg observatory, starting in 1967, the most striking features are increases of sim2.2% per year in all tropospheric heights up to 8 km during the past 24 years. These facts have recently been published and discussed by several authors. In this paper, we present some evidence for the increase of tropospheric ozone concentrations during the past 50 years 1940-1990 in the territory of the northern edge of the Bavarian Alps, including the Hohenpeißenberg data. In December 1940 and August 1942, probably the first exact wet-chemical vertical soundings of ozone up to 9 km height were made by an aircraft in the region mentioned. These results were published in the earlier literature. We have converted the results of the flights on 4 days in December 1940 and on 6 days in August 1942 to modern units and have compared them with the Hohenpeißenberg ozone-sonde data of the December and August months. We also compared the data at the ground with the August results of Paris-Montsouris 1886-1898. Our results show an increase of ozone concentration at all tropospheric heights in Upper Bavaria during the past 50 years, compared with the Montsouris data in August during the past 105 years. In the recently published papers, the increases since 1967 were approximated linearly.Our results, extended to the past, show non-linear trends, with steeper increases since 1975-1979. Possible reasons for these findings are discussed. Quite recently (in case of the December months since 1986/87, the August months since 1990, the ozone mixing ratios at and above Hohenpeißenberg seem to have decreased.

Evidence of a 50-year increase in tropospheric ozone in Upper Bavaria

Directory of Open Access Journals (Sweden)

M. Schmidt

1994-12-01

Full Text Available In a series of ozone-sonde soundings at the Hohenpeißenberg observatory, starting in 1967, the most striking features are increases of \\sim2.2% per year in all tropospheric heights up to 8 km during the past 24 years. These facts have recently been published and discussed by several authors. In this paper, we present some evidence for the increase of tropospheric ozone concentrations during the past 50 years 1940-1990 in the territory of the northern edge of the Bavarian Alps, including the Hohenpeißenberg data. In December 1940 and August 1942, probably the first exact wet-chemical vertical soundings of ozone up to 9 km height were made by an aircraft in the region mentioned. These results were published in the earlier literature. We have converted the results of the flights on 4 days in December 1940 and on 6 days in August 1942 to modern units and have compared them with the Hohenpeißenberg ozone-sonde data of the December and August months. We also compared the data at the ground with the August results of Paris-Montsouris 1886-1898. Our results show an increase of ozone concentration at all tropospheric heights in Upper Bavaria during the past 50 years, compared with the Montsouris data in August during the past 105 years. In the recently published papers, the increases since 1967 were approximated linearly.Our results, extended to the past, show non-linear trends, with steeper increases since 1975-1979. Possible reasons for these findings are discussed. Quite recently (in case of the December months since 1986/87, the August months since 1990, the ozone mixing ratios at and above Hohenpeißenberg seem to have decreased.

Effect of ozone concentration on silicon surface passivation by atomic layer deposited Al{sub 2}O{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Gastrow, Guillaume von, E-mail: guillaume.von.gastrow@aalto.fi [Aalto University, Department of Micro- and Nanosciences, Tietotie 3, 02150 Espoo (Finland); Li, Shuo [Aalto University, Department of Micro- and Nanosciences, Tietotie 3, 02150 Espoo (Finland); Putkonen, Matti [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT, Espoo (Finland); Aalto University School of Chemical Technology, Laboratory of Inorganic Chemistry, FI-00076 Aalto, Espoo (Finland); Laitinen, Mikko; Sajavaara, Timo [University of Jyvaskyla, Department of Physics, FIN-40014 University of Jyvaskyla (Finland); Savin, Hele [Aalto University, Department of Micro- and Nanosciences, Tietotie 3, 02150 Espoo (Finland)

2015-12-01

Highlights: • The ALD Al{sub 2}O{sub 3} passivation quality can be controlled by the ozone concentration. • Ozone concentration affects the Si/Al{sub 2}O{sub 3} interface charge and defect density. • A surface recombination velocity of 7 cm/s is reached combining ozone and water ALD. • Carbon and hydrogen concentrations correlate with the surface passivation quality. - Abstract: We study the impact of ozone-based Al{sub 2}O{sub 3} Atomic Layer Deposition (ALD) on the surface passivation quality of crystalline silicon. We show that the passivation quality strongly depends on the ozone concentration: the higher ozone concentration results in lower interface defect density and thereby improved passivation. In contrast to previous studies, our results reveal that too high interface hydrogen content can be detrimental to the passivation. The interface hydrogen concentration can be optimized by the ozone-based process; however, the use of pure ozone increases the harmful carbon concentration in the film. Here we demonstrate that low carbon and optimal hydrogen concentration can be achieved by a single process combining the water- and ozone-based reactions. This process results in an interface defect density of 2 × 10{sup 11} eV{sup −1} cm{sup −2}, and maximum surface recombination velocities of 7.1 cm/s and 10 cm/s, after annealing and after an additional firing at 800 °C, respectively. In addition, our results suggest that the effective oxide charge density can be optimized in a simple way by varying the ozone concentration and by injecting water to the ozone process.

Effects of simultaneous ozone exposure and nitrogen loads on carbohydrate concentrations, biomass, and growth of young spruce trees (Picea abies)

International Nuclear Information System (INIS)

Thomas, V.F.D.; Braun, S.; Flueckiger, W.

2005-01-01

Spruce saplings were grown under different nitrogen fertilization regimes in eight chamberless fumigation systems, which were fumigated with either charcoal-filtered (F) or ambient air (O 3 ). After the third growing season trees were harvested for biomass and non-structural carbohydrate analysis. Nitrogen had an overall positive effect on the investigated plant parameters, resulting in increased shoot elongation, biomass production, fine root soluble carbohydrate concentrations, and also slightly increased starch concentrations of stems and roots. Only needle starch concentrations and fine root sugar alcohol concentrations were decreased. Ozone fumigation resulted in needle discolorations and affected most parameters negatively, including decreased shoot elongation and decreased starch concentrations in roots, stems, and needles. In fine roots, however, soluble carbohydrate concentrations remained unaffected or increased by ozone fumigation. The only significant interaction was an antagonistic effect on root starch concentrations, where higher nitrogen levels alleviated the negative impact of ozone. - Simultaneous ozone fumigation and nitrogen fertilization have no synergistic impacts on carbohydrate concentrations, biomass, or growth of Picea abies saplings

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

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

Dependence of Initial Oxygen Concentration on Ozone Yield Using Inductive Energy Storage System Pulsed Power Generator

Science.gov (United States)

Go, Tomio; Tanaka, Yasushi; Yamazaki, Nobuyuki; Mukaigawa, Seiji; Takaki, Koichi; Fujiwara, Tamiya

Dependence of initial oxygen concentration on ozone yield using streamer discharge reactor driven by an inductive energy storage system pulsed power generator is described in this paper. Fast recovery type diodes were employed as semiconductor opening switch to interrupt a circuit current within 100 ns. This rapid current change produced high-voltage short pulse between a secondary energy storage inductor. The repetitive high-voltage short pulse was applied to a 1 mm diameter center wire electrode placed in a cylindrical pulse corona reactor. The streamer discharge successfully occurred between the center wire electrode and an outer cylinder ground electrode of 2 cm inner diameter. The ozone was produced with the streamer discharge and increased with increasing pulse repetition rate. The ozone yield changed in proportion to initial oxygen concentration contained in the injected gas mixture at 800 ns forward pumping time of the current. However, the decrease of the ozone yield by decreasing oxygen concentration in the gas mixture at 180 ns forward pumping time of the current was lower than the decrease at 800 ns forward pumping time of the current. This dependence of the initial oxygen concentration on ozone yield at 180 ns forward pumping time is similar to that of dielectric barrier discharge reactor.

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

Physiological responses of Pinus sylvestris to changing carbon dioxide and ozone concentrations

Energy Technology Data Exchange (ETDEWEB)

Holopainen, T [Kuopio Univ. (Finland). Dept. of Ecology and Environmental Science; Palomaeki, V [Joensuu Univ. (Finland). Faculty of Forestry; Helmisaari, H S [Finnish Forest Research Inst., Helsinki (Finland); and others

1997-12-31

The objective of this research is to study the effects of elevated ozone, carbon dioxide and their combination on ultrastructural, physiological and biochemical responses of Scots pine needles and how these effects are reflected to photosynthesis, carbohydrate and nutrient allocation and finally to shoot and root growth of trees. In addition the interactions of the studied trees and mycorrhizal fungi as well as insect herbivores are studied. The exposures have been running only for two growing periods and it seems necessary to continue the experiment over the third growing season in 1996. Since the analyses are partially incomplete, only preliminary conclusions are possible at the moment. The slightly increased shoot growth and needle width and increased amount of starch in chloroplasts point to the slight stimulating effect of elevated CO{sub 2} among the chamber treatments. Altogether the growth of the seedlings was best in the chamberless treatment indicating a negative chamber effect. The elevated ozone significantly increased the chlorotic mottling and overall yellowing of second year needles as well as caused increased density of chloroplast stroma and declined photosynthesis, all these responses being often related to ozone exposures. The ozone related responses appeared at both CO{sub 2} levels indicating no clear protection due to elevated CO{sub 2}. The ozone or carbon dioxide treatments were not able to significantly change nutrient concentrations, insect herbivory or carbon allocation among the secondary compounds of needles. A tendency of increased carbon allocation to fine roots due to ozone but not so clearly to CO{sub 2} was observed

Physiological responses of Pinus sylvestris to changing carbon dioxide and ozone concentrations

Energy Technology Data Exchange (ETDEWEB)

Holopainen, T. [Kuopio Univ. (Finland). Dept. of Ecology and Environmental Science; Palomaeki, V. [Joensuu Univ. (Finland). Faculty of Forestry; Helmisaari, H.S. [Finnish Forest Research Inst., Helsinki (Finland)] [and others

1996-12-31

The objective of this research is to study the effects of elevated ozone, carbon dioxide and their combination on ultrastructural, physiological and biochemical responses of Scots pine needles and how these effects are reflected to photosynthesis, carbohydrate and nutrient allocation and finally to shoot and root growth of trees. In addition the interactions of the studied trees and mycorrhizal fungi as well as insect herbivores are studied. The exposures have been running only for two growing periods and it seems necessary to continue the experiment over the third growing season in 1996. Since the analyses are partially incomplete, only preliminary conclusions are possible at the moment. The slightly increased shoot growth and needle width and increased amount of starch in chloroplasts point to the slight stimulating effect of elevated CO{sub 2} among the chamber treatments. Altogether the growth of the seedlings was best in the chamberless treatment indicating a negative chamber effect. The elevated ozone significantly increased the chlorotic mottling and overall yellowing of second year needles as well as caused increased density of chloroplast stroma and declined photosynthesis, all these responses being often related to ozone exposures. The ozone related responses appeared at both CO{sub 2} levels indicating no clear protection due to elevated CO{sub 2}. The ozone or carbon dioxide treatments were not able to significantly change nutrient concentrations, insect herbivory or carbon allocation among the secondary compounds of needles. A tendency of increased carbon allocation to fine roots due to ozone but not so clearly to CO{sub 2} was observed

Semiconductor Sensors for Studying the Heterogeneous Destruction of Ozone at Low Concentrations

Science.gov (United States)

Obvintseva, L. A.; Sharova, T. B.; Avetisov, A. K.; Sukhareva, I. P.

2018-06-01

Prospects for the use of semiconductor resistive sensors in studies of the heterogeneous destruction of ozone at low concentrations (5-400 μg/m3) were shown. The influence of various factors (sensor temperature, gas flow rate, ozone concentration) on the results of ozone concentration measurements with sensors of various types was studied. Methods for forming a sensitive layer of In2O3(3% Fe2O3) sensors with specified parameters of calibration curves were proposed. The optimum conditions for the operation of sensors in a flow mode were formulated. The results of the study of heterogeneous destruction of ozone on microfiber polymer and natural disperse (sand, coals) materials obtained by the developed method were presented.

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

Ozone in the Upper Silesia region -- concentration and effects on plants

Science.gov (United States)

Stefan Godzik

1998-01-01

In the Beskidy Mountains at Brenna, Poland, and several other locations in the Katowice administrative district, plants were used as bioindicators to determine ozone concentration measurements in 1994 and 1995. Results showed that ozone is the only gaseous air pollutant significantly exceeding the permissible concentrations and causing foliar injury to both test and...

Changes in concentrations of triazine and acetamide herbicides by bank filtration, ozonation, and chlorination in a public water supply

Science.gov (United States)

Verstraeten, Ingrid M.; Thurman, E.M.; Lindsey, M.E.; Lee, E.C.; Smith, R.D.

2002-01-01

The changes in triazine and acetamide concentrations in water during natural and artificial treatment by bank filtration, ozonation, filtration, and chlorination were measured at the well field and drinking water treatment plant of Lincoln, Nebraska, USA. The city's groundwater supply is affected by induced infiltration and transport of triazines and acetamide herbicides from the Platte River in late spring and early summer. The objective of the study was to evaluate the effect of infiltration and treatment on the presence of triazines and acetamides in drinking water. Samples of river water, well water, and public supply water at various stages of water treatment were collected from 1997-1999 during spring-runoff when the presence of herbicides in the Platte River is largest. In 1999, parent compounds were reduced by 76% of the concentration present in river water (33% by bank filtration, 41% by ozonation, and 1.5% by chlorination). Metabolites of herbicides for which analytical techniques existed were reduced by 21% (plus 26% by bank filtration, minus 23% by ozonation, and minus 24% by chlorination). However, increases in concentrations of specific metabolite compounds were identified after bank filtration and ozonation. After bank filtration, increases in cyanazine amide, cyanazine acid, and deethylcyanazine acid were identified. After ozonation, concentrations of deisopropylatrazine, deethylatrazine, didealkylatrazine, atrazine amide-I, hydroxydeethylatrazine, hydroxydeisopopylatrazine, deethylcyanazine acid, and deethylcyanazine increased. Concentrations of cyanazine acid and ethanesulfonic and oxanilic acids of acetamides decreased during ozonation. Our findings suggest that bank filtration and ozonation of water in part can shift the assessment of risk to human health associated with the consumption of the water from the parent compounds to their degradation products.

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.

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...

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.

Influence of duration and rate of pulse rise of the applied voltage on ozone concentration in the barrier glow discharge

International Nuclear Information System (INIS)

Krasnyj, V.V.; Klosovski, A.V.; Knysh, A.S.; Shvets, O.M.; Taran, V.S.; Tereshin, V.I.

2005-01-01

The barrier glow discharge between two planar electrodes, covered with dielectric, is studied under high-voltage pulsed power supply. Wide applications of such type of discharges, in particular, for ozone production, stimulated a number of investigations in this direction. In this work we investigated the dependence of ozone concentration on the duration and the rate of pulse rise of the applied voltage. The thyristor converter circuit with the shortening of input pulses on the base of the saturable throttle was used for the realization of this task. The output pulses with amplitude up to 15 kV, repetition frequency of 1 kHz, pulse duration of 0.3 μs (or 7 μs) and the rate of pulse rise of 0.1 μs were generated with this scheme. Measurements of the ozone concentration produced in the air mixture have shown that its value increased by factor two with variation of the rate of pulse rise from 0.5 μs to 0.1 μs (for pulse duration of 7 μs). The dependence of the ozone concentration on the variation of air mixture pressure in the discharge gap of reactor was investigated also. It was shown proportional increase of the output concentration of ozone with increasing the pressure value. Spectroscopic measurements carried out in the ultraviolet spectrum made it possible to analyze changing the concentration of ozone and nitric components. (author)

Synoptic and meteorological drivers of extreme ozone concentrations over Europe

Science.gov (United States)

Otero, Noelia Felipe; Sillmann, Jana; Schnell, Jordan L.; Rust, Henning W.; Butler, Tim

2016-04-01

The present work assesses the relationship between local and synoptic meteorological conditions and surface ozone concentration over Europe in spring and summer months, during the period 1998-2012 using a new interpolated data set of observed surface ozone concentrations over the European domain. Along with local meteorological conditions, the influence of large-scale atmospheric circulation on surface ozone is addressed through a set of airflow indices computed with a novel implementation of a grid-by-grid weather type classification across Europe. Drivers of surface ozone over the full distribution of maximum daily 8-hour average values are investigated, along with drivers of the extreme high percentiles and exceedances or air quality guideline thresholds. Three different regression techniques are applied: multiple linear regression to assess the drivers of maximum daily ozone, logistic regression to assess the probability of threshold exceedances and quantile regression to estimate the meteorological influence on extreme values, as represented by the 95th percentile. The relative importance of the input parameters (predictors) is assessed by a backward stepwise regression procedure that allows the identification of the most important predictors in each model. Spatial patterns of model performance exhibit distinct variations between regions. The inclusion of the ozone persistence is particularly relevant over Southern Europe. In general, the best model performance is found over Central Europe, where the maximum temperature plays an important role as a driver of maximum daily ozone as well as its extreme values, especially during warmer months.

Near-ambient ozone concentrations reduce the vigor of Betula and Populus species in Finland.

Science.gov (United States)

Oksanen, Elina; Manninen, Sirkku; Vapaavuori, Elina; Holopainen, Toini

2009-12-01

In this review the main growth responses of Finnish birch (Betula pendula, B. pubescens) and aspen species (Populus tremula and P. tremuloides x P. tremula) are correlated with ozone exposure, indicated as the AOT40 value. Data are derived from 23 different laboratory, open-top chamber, and free-air fumigation experiments. Our results indicate that these tree species are sensitive to increasing ozone concentrations, though high intraspecific variation exists. The roots are the most vulnerable targets in both genera. These growth reductions, determined from trees grown under optimal nutrient and water supply, were generally accompanied by increased visible foliar injuries, carbon allocation toward defensive compounds, reduced carbohydrate contents of leaves, impaired photosynthesis processes, disturbances in stomatal function, and earlier autumn senescence. Because both genera have shown complex ozone defense and response mechanisms, which are modified by variable environmental conditions, a mechanistically based approach is necessary for accurate ozone risk assessment.

Surface ozone concentrations in Europe: Links with the regional-scale atmospheric circulation

Science.gov (United States)

Davies, T. D.; Kelly, P. M.; Low, P. S.; Pierce, C. E.

1992-06-01

Daily surface ozone observations from 1978 (1976 for some analyses) to 1988 for Bottesford (United Kingdom), Cabauw, Kloosterburen (The Netherlands), Hohenpeissenberg, Neuglobsow, Hamburg, and Arkona (Germany) are used to analyze links between surface ozone variations and the atmospheric circulation. A daily Europe-wide synoptic classification highlights marked differences between surface ozone/meteorology relationships in summer and winter. These relationships are characterized by correlations between daily surface ozone concentrations at each station and a local subregional surface pressure gradient (a wind speed index). Although there are geographical variations, which are explicable in terms of regional climatology, there are distinct annual cycles. In summer, the surface ozone/wind speed relationship exhibits the expected negative sign; however, in winter, the relationship is, in the main, strongly positive, especially at those stations which are more influenced by the vigorous westerlies. Spring and autumn exhibit negative, positive, or transitional (between summer and winter) behavior, depending on geographical position. It is suggested that these relationships reflect the importance of vertical exchange from the free troposphere to the surface in the nonsummer months. Composite surface pressure patterns and surface pressure anomaly (from the long-term mean) patterns associated with high surface ozone concentrations on daily and seasonal time scales are consistent with the surface ozone/wind speed relationships. Moreover, they demonstrate that high surface ozone concentrations, in a climatological time frame, can be associated with mean surface pressure patterns which have a synoptic reality and are robust. Such an approach may be useful in interpreting past variations in surface ozone and may help to isolate the effect of human activity. It is also possible that assessments can be made of the effect of projected future changes in the atmospheric circulation

Silver birch and climate change: variable growth and carbon allocation responses to elevated concentrations of carbon dioxide and ozone

International Nuclear Information System (INIS)

Riikonen, J.; Holopainen, T.; Oksanen, E.; Lindsberg, M-M.; Lappi, J.; Peltonen, P.; Vapaavuori, E.

2004-01-01

The effects of elevated concentrations of carbon dioxide and ozone were studied on growth, biomass allocation and leaf area of field-grown ozone-tolerant (Clone 4) and ozone-sensitive (Clone 80) European silver birch trees. Seven-year old trees of both types were exposed for three years to outside and chamber control, (1) twice ambient ozone, (2) twice ambient carbon dioxide, and (3) twice ambient carbon dioxide and twice ambient ozone. No effect on biomass allocation was observed when results of the two clones were analyzed together. Total leaf area showed an increase, and leaf abscission appeared delayed in response to elevated carbon dioxide. Elevated ozone caused the dry mass of roots, branches and mean leaf size to decrease, and autumnal leaf abscission occurred earlier than usual in both clones. In general. the effects of elevated ozone were small, however, the interaction between elevated carbon dioxide and elevated oxygen were significant. When results from the two clones were analyzed separately, stem diameter, volume growth and total biomass of Clone 80 increased when exposed to elevated concentrations of carbon dioxide; elevated concentrations of ozone appeared to have no effect. In Clone 4 elevated ozone caused significant decrease in root and branch biomass, but the effects of elevated carbon dioxide were minimal. Responses to elevated ozone exposure were observed only under ambient carbon dioxide conditions. This response is believed to reflect the greater quantity of carbohydrates available for detoxification and repair under elevated carbon dioxide conditions. Alternatively, the response may be due to decreased stomatal conductance, thus decreased ozone uptake under elevated carbon dioxide conditions. 45 refs., 6 tabs., 4 figs

Contribution of anthropogenic pollutants to the increase of tropospheric ozone levels in the Oporto Metropolitan Area, Portugal since the 19th century

International Nuclear Information System (INIS)

Alvim-Ferraz, M.C.M.; Sousa, S.I.V.; Pereira, M.C.; Martins, F.G.

2006-01-01

The main purpose of this study was to evaluate the contribution of anthropogenic pollutants to the increase of tropospheric ozone levels in the Oporto Metropolitan Area (Portugal) since the 19th century. The study was based on pre-industrial and recent data series, the results being analyzed according to the atmospheric chemistry. The treatment of ozone and meteorological data was performed by classical statistics and by time-series analysis. It was concluded that in the 19th century the ozone present in the troposphere was not of photochemical origin, being possible to consider the respective concentrations as reference values. For recent data a cycle of 8 h for ozone concentrations could be related to traffic. Compared to the 19th century, the current concentrations were 147% higher (252% higher in May) due to the increased photochemical production associated with the increased anthropogenic emissions. - Compared to the 19th century, the current ozone concentrations are 147% higher at Oporto, Portugal

Ozone synthesis improves by increasing number density of plasma channels and lower voltage in a nonthermal plasma

Science.gov (United States)

Arif Malik, Muhammad; Hughes, David

2016-04-01

Improvements in ozone synthesis from air and oxygen by increasing the number density of plasma channels and lower voltage for the same specific input energy (SIE) were explored in a nonthermal plasma based on a sliding discharge. The number of plasma channels and energy per pulse increased in direct proportion to the increase in the effective length of the anode (the high voltage electrode). Decreasing the discharge gap increased the energy per pulse for the same length and allowed the installation of more electrode pairs in the same space. It allowed the increase of the number of plasma channels in the same space to achieve the same SIE at a lower peak voltage with less energy per plasma channel. The ozone concentration gradually increased to ~1500 ppmv (140 to 50 g kWh-1) from air and to ~6000 ppmv (400 to 200 g kWh-1) from oxygen with a gradual increase in the SIE to ~200 J L-1, irrespective of the variations in electrode geometry, applied voltage or flow rate of the feed gas. A gradual increase in SIE beyond 200 J L-1 gradually increased the ozone concentration to a certain maximum value followed by a decline, but the rate of increase and the maximum value was higher for the greater number of plasma channels and lower peak voltage combination. The maximum ozone concentration was ~5000 ppmv (~30 g kWh-1) from air and ~22 000 ppmv (~80 g kWh-1) from oxygen. The results are explained on the basis of characteristics of the plasma and ozone synthesis mechanism.

Principal Component Analysis of Chlorophyll Content in Tobacco, Bean and Petunia Plants Exposed to Different Tropospheric Ozone Concentrations

Science.gov (United States)

Borowiak, Klaudia; Zbierska, Janina; Budka, Anna; Kayzer, Dariusz

2014-06-01

Three plant species were assessed in this study - ozone-sensitive and -resistant tobacco, ozone-sensitive petunia and bean. Plants were exposed to ambient air conditions for several weeks in two sites differing in tropospheric ozone concentrations in the growing season of 2009. Every week chlorophyll contents were analysed. Cumulative ozone effects on the chlorophyll content in relation to other meteorological parameters were evaluated using principal component analysis, while the relation between certain days of measurements of the plants were analysed using multivariate analysis of variance. Results revealed variability between plant species response. However, some similarities were noted. Positive relations of all chlorophyll forms to cumulative ozone concentration (AOT 40) were found for all the plant species that were examined. The chlorophyll b/a ratio revealed an opposite position to ozone concentration only in the ozone-resistant tobacco cultivar. In all the plant species the highest average chlorophyll content was noted after the 7th day of the experiment. Afterwards, the plants usually revealed various responses. Ozone-sensitive tobacco revealed decrease of chlorophyll content, and after few weeks of decline again an increase was observed. Probably, due to the accommodation for the stress factor. While during first three weeks relatively high levels of chlorophyll contents were noted in ozone-resistant tobacco. Petunia revealed a slow decrease of chlorophyll content and the lowest values at the end of the experiment. A comparison between the plant species revealed the highest level of chlorophyll contents in ozone-resistant tobacco.

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.

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).

Ozone exposure increases respiratory epithelial permeability in humans

International Nuclear Information System (INIS)

Kehrl, H.R.; Vincent, L.M.; Kowalsky, R.J.; Horstman, D.H.; O'Neil, J.J.; McCartney, W.H.; Bromberg, P.A.

1987-01-01

Ozone is a respiratory irritant that has been shown to cause an increase in the permeability of the respiratory epithelium in animals. We used inhaled aerosolized /sup 99m/Tc-labeled diethylene triamine pentacetic acid (/sup 99m/Tc-DTPA) to investigate whether human respiratory epithelial permeability is similarly affected by exposure to ozone. In a randomized, crossover double-blinded study, 8 healthy, nonsmoking young men were exposed for 2 h to purified air and 0.4 ppm ozone while performing intermittent high intensity treadmill exercise (minute ventilation = 66.8 L/min). SRaw and FVC were measured before and at the end of exposures. Seventy-five minutes after the exposures, the pulmonary clearance of /sup 99m/Tc-DTPA was measured by sequential posterior lung imaging with a computer-assisted gamma camera. Ozone exposure caused respiratory symptoms in all 8 subjects and was associated with a 14 +/- 2.8% (mean +/- SEM) decrement in FVC (p less than 0.001) and a 71 +/- 22% increase in SRaw (p = 0.04). Compared with the air exposure day, 7 of the 8 subjects showed increased /sup 99m/Tc-DTPA clearance after the ozone exposure, with the mean value increasing from 0.59 +/- 0.08 to 1.75 +/- 0.43%/min (p = 0.03). These data show that ozone exposure sufficient to produce decrements in the pulmonary function of human subjects also causes an increase in /sup 99m/Tc-DTPA clearance

The predicted impact of VOCs from Marijuana cultivation operations on ozone concentrations in great Denver, CO.

Science.gov (United States)

Wang, C. T.; Vizuete, W.; Wiedinmyer, C.; Ashworth, K.

2016-12-01

Colorado is the first the marijuana legal states in the United States since 2014. As a result, thousands of legal Marijuana cultivation operations are at great Denver area now. Those Marijuana cultivation operations could be the potential to release a lot of biogenic VOCs, such as monoterpene(C10H16), alpha-pinene, and D-limonene. Those alkene species could rapidly increase the peroxy radicals and chemical reactions in the atmosphere, especially in the urban area which belong to VOC-limited ozone regime. These emissions will increase the ozone in Denver city, where is ozone non-attainment area. Some previous research explained the marijuana smoke and indoor air quality (Martyny, Serrano, Schaeffer, & Van Dyke, 2013) and the smell of marijuana chemical compounds(Rice & Koziel, 2015). However, there have been no studies discuss on identifying and assessing emission rate from marijuana and how those species impact on atmospheric chemistry and ozone concentration, and the marijuana emissions have been not considered in the national emission inventory, either. This research will use air quality model to identify the possibility of ozone impact by marijuana cultivation emission. The Comprehensive Air Quality Model with Extensions, CAMx, are applied for this research to identify the impact of ozone concentration. This model is government regulatory model based on the Three-State Air Quality Modeling Study (3SAQS), which developed by UNC-Chapel Hill and ENVIRON in 2012. This model is used for evaluation and regulate the ozone impact in ozone non-attainment area, Denver city. The details of the 3SAQS model setup and protocol can be found in the 3SAQS report(UNC-IE, 2013). For the marijuana emission study scenarios, we assumed the monoterpene (C10H16) is the only emission species in air quality model and identify the ozone change in the model by the different quantity of emission rate from marijuana cultivation operations.

Modelling horizontal and vertical concentration profiles of ozone and oxides of nitrogen within high-latitude urban areas

International Nuclear Information System (INIS)

Nicholson, J.P.; Weston, K.J.

2001-01-01

Urban ozone concentrations are determined by the balance between ozone destruction, chemical production and supply through advection and turbulent down-mixing from higher levels. At high latitudes, low levels of solar insolation and high horizontal advection speeds reduce the photochemical production and the spatial ozone concentration patterns are largely determined by the reaction of ozone with nitric oxide and dry deposition to the surface. A Lagrangian column model has been developed to simulate the mean (monthly and annual) three-dimensional structure in ozone and nitrogen oxides (NO x ) concentrations in the boundary-layer within and immediately around an urban area. The short-time-scale photochemical processes of ozone and NO x , as well as emissions and deposition to the ground, are simulated. The model has a horizontal resolution of 1x1km and high resolution in the vertical. It has been applied over a 100x100km domain containing the city of Edinburgh (at latitude 56 o N) to simulate the city-scale processes of pollutants. Results are presented, using averaged wind-flow frequencies and appropriate stability conditions, to show the extent of the depletion of ozone by city emissions. The long-term average spatial patterns in the surface ozone and NO x concentrations over the model domain are reproduced quantitatively. The model shows the average surface ozone concentrations in the urban area to be lower than the surrounding rural areas by typically 50% and that the areas experiencing a 20% ozone depletion are generally restricted to within the urban area. The depletion of the ozone concentration to less than 50% of the rural surface values extends only 20m vertically above the urban area. A series of monitoring sites for ozone, nitric oxide and nitrogen dioxide on a north-south transect through the city - from an urban, through a semi-rural, to a remote rural location - allows the comparison of modelled with observed data for the mean diurnal cycle of ozone

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.

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.

The role and importance of ozone for atmospheric chemistry and methods for measuring its concentration

Directory of Open Access Journals (Sweden)

Marković Dragan M.

2003-01-01

Full Text Available Depending on where ozone resides, it can protect or harm life on Earth. The thin layer of ozone that surrounds Earth acts as a shield protecting the planet from irradiation by UV light. When it is close to the planet's surface, ozone is a powerful photochemical oxidant that damage, icons frescos, museum exhibits, rubber, plastic and all plant and animal life. Besides the basic properties of some methods for determining the ozone concentration in working and living conditions, this paper presents a detailed description of the electrochemical method. The basic properties of the electrochemical method are used in the construction of mobile equipment for determining the sum of oxidants in the atmosphere. The equipment was used for testing the determination of the ozone concentration in working rooms, where the concentration was at a high level and caused by UV radiation or electrostatic discharge. According to the obtained results, it can be concluded that this equipment for determining the ozone concentration in the atmosphere is very powerful and reproducible in measurements.

Ozone concentrations in the Brazilian Amazonia during BASE-A

International Nuclear Information System (INIS)

Setzer, A.W.; Kirchhoff, V.W.J.H.; Pereira, M.C.

1991-01-01

During the Biomass Burning Airborne and Spaceborne Experiment--Amazonia, thermal images of fires were made with the Advanced Very High Resolution Radiometer (AVHRR) on board meteorological NOAA series satellites. The results of ozone measurements made on board the Brazilian Institute for Space Research (INPE) airplane during September of 1989 are presented and analyzed in relation to the temporal and geographical location of fires detected before and during the sampling. Results show that on a synoptic scale, concentrations of ozone rise sharply in regions of more intense burning

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.

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.

Investigating the effect of gas flow rate, inlet ozone concentration and relative humidity on the efficacy of catalytic ozonation process in the removal of xylene from waste airstream

Directory of Open Access Journals (Sweden)

H.R. MokaramI

2010-10-01

Full Text Available Background and aimsThe catalytic ozonation is an efficient process for the degradation of volatile organic compounds from contaminated air stream. This study was aimed at investigating the efficacy of catalytic ozonation process in removal of xylene from the polluted air stream andthe influence of retention time (gas flow rate, inlet ozone dose and relative humidity on this performanceMethodsthe catalytic ozonation of xylene was conducted using a bench scale set-up consisted of a syringe pump,an air pump, an ozone generator, and a glass reactor packed with activated carbon. Several experimental run was defined to investigate the influence of the selectedoperational variables.ResultsThe results indicated that the efficiency of catalytic ozonation was greater than that of single adsorption in removal of xylene under similar inlet concentration and relative humidity. We found a significant catalytic effect for activated carbon when used in combination with ozonation process, leading to improvement of xylene removal percentage. In addition, the elimination capacity of the system improved with the increase of inlet ozone dose as well as gas flow rate. The relative humidity showed a positive effect of the xylene removal at the range of 5 to 50%, while the higher humidity (more than 50% resulted in reduction of the performance.ConclusionThe findings of the present work revealed that the catalytic ozonation process can be an efficient technique for treating the air streams containing industrial concentrations of xylene. Furthermore, there is a practical potential to retrofit the present adsorption systems intothe catalytic ozonation simply by coupling them with the ozonation system. the catalytic ozonation of xylene was conducted using a bench scale set-up consisted of a syringe pump,an air pump, an ozone generator, and a glass reactor packed with activated carbon. Several experimental run was defined to investigate the influence of the selected

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.

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.

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

Fitting Statistical Distributions Functions on Ozone Concentration Data at Coastal Areas

International Nuclear Information System (INIS)

Muhammad Yazid Nasir; Nurul Adyani Ghazali; Muhammad Izwan Zariq Mokhtar; Norhazlina Suhaimi

2016-01-01

Ozone is known as one of the pollutant that contributes to the air pollution problem. Therefore, it is important to carry out the study on ozone. The objective of this study is to find the best statistical distribution for ozone concentration. There are three distributions namely Inverse Gaussian, Weibull and Lognormal were chosen to fit one year hourly average ozone concentration data in 2010 at Port Dickson and Port Klang. Maximum likelihood estimation (MLE) method was used to estimate the parameters to develop the probability density function (PDF) graph and cumulative density function (CDF) graph. Three performance indicators (PI) that are normalized absolute error (NAE), prediction accuracy (PA), and coefficient of determination (R 2 ) were used to determine the goodness-of-fit criteria of the distribution. Result shows that Weibull distribution is the best distribution with the smallest error measure value (NAE) at Port Klang and Port Dickson is 0.08 and 0.31, respectively. The best score for highest adequacy measure (PA: 0.99) with the value of R 2 is 0.98 (Port Klang) and 0.99 (Port Dickson). These results provide useful information to local authorities for prediction purpose. (author)

Multi-year ozone concentration and its spectra in Shanghai, China

Energy Technology Data Exchange (ETDEWEB)

Geng, Fuhai; Mao, Xiaoqin [Shanghai Meteorological Bureau, Shanghai (China); Shanghai Key Laboratory of Meteorology and Health, Shanghai (China); Zhou, Mingyu, E-mail: mingyuzhou34@163.com [National Marine Environmental Forecasts Center, State Oceanic Administration, Beijing (China); Zhong, Shiyuan [Department of Geography, Michigan State University, East Lansing, MI (United States); Lenschow, Donald [National Center for Atmospheric Research, Boulder, CO (United States)

2015-07-15

The periodic properties of surface ozone variation were studied at five stations with different environmental conditions in Shanghai based on multi-year observations of ozone concentration and UV radiation using spectral decomposition methods. The spectra of surface ozone have distinct peaks at semi-diurnal, diurnal, intraseasonal, semiannual, annual, and quasi-biennial periods. The spectra for the frequency band larger than the semi-diurnal follow a − 5/3 power law at all the stations. The diurnal peak values for all stations in different years are similar to each other, while the semi-diurnal peak values are somewhat different among the stations. The peak value of semi-diurnal cycle at the station Dongtan (ecological environment area) is smaller than that at the other stations. The monthly mean of surface ozone has a significant seasonal variation with a maximum in May, a secondary maximum in fall, a lower value in summer (July and August), and a minimum in December or January. However the seasonal variation of UV radiation monthly mean shows a relatively higher value in summer (July and August), and for other months it is closely related to the ozone monthly mean. These secondary peaks of the ozone monthly mean in fall might be caused by the UV radiation coming back to its relevant value after falling off during the Asia summer monsoon; it was not related to biomass burning. The intraseasonal cycling of ozone might be related to the MJO (Madden–Julian Oscillation). Further studies are needed to understand the relationship between the local ozone intraseasonal variation and the MJO. The quasi-biennial variation of ozone in Shanghai might be a local reflection of climate change and could be associated with ENSO (El-Nino Southern Oscillation). Further studies will be needed to understand the relationship of the quasi-biennial variation of ozone to ENSO. - Highlights: • The spectral decomposition methods are used. • The spectra of surface ozone have multi

Multi-year ozone concentration and its spectra in Shanghai, China

International Nuclear Information System (INIS)

Geng, Fuhai; Mao, Xiaoqin; Zhou, Mingyu; Zhong, Shiyuan; Lenschow, Donald

2015-01-01

The periodic properties of surface ozone variation were studied at five stations with different environmental conditions in Shanghai based on multi-year observations of ozone concentration and UV radiation using spectral decomposition methods. The spectra of surface ozone have distinct peaks at semi-diurnal, diurnal, intraseasonal, semiannual, annual, and quasi-biennial periods. The spectra for the frequency band larger than the semi-diurnal follow a − 5/3 power law at all the stations. The diurnal peak values for all stations in different years are similar to each other, while the semi-diurnal peak values are somewhat different among the stations. The peak value of semi-diurnal cycle at the station Dongtan (ecological environment area) is smaller than that at the other stations. The monthly mean of surface ozone has a significant seasonal variation with a maximum in May, a secondary maximum in fall, a lower value in summer (July and August), and a minimum in December or January. However the seasonal variation of UV radiation monthly mean shows a relatively higher value in summer (July and August), and for other months it is closely related to the ozone monthly mean. These secondary peaks of the ozone monthly mean in fall might be caused by the UV radiation coming back to its relevant value after falling off during the Asia summer monsoon; it was not related to biomass burning. The intraseasonal cycling of ozone might be related to the MJO (Madden–Julian Oscillation). Further studies are needed to understand the relationship between the local ozone intraseasonal variation and the MJO. The quasi-biennial variation of ozone in Shanghai might be a local reflection of climate change and could be associated with ENSO (El-Nino Southern Oscillation). Further studies will be needed to understand the relationship of the quasi-biennial variation of ozone to ENSO. - Highlights: • The spectral decomposition methods are used. • The spectra of surface ozone have multi

Forecasting ozone concentrations in the east of Croatia using ...

Indian Academy of Sciences (India)

for urban and another one for rural area in the eastern part of Croatia. ... 2010). Apart from the negative impact on respiratory system, atmo- ..... Figure 3. Daily average ozone concentrations in the rural (Tikveš) and urban (Osijek) areas.

Impact of Cabin Ozone Concentrations on Passenger Reported Symptoms in Commercial Aircraft

DEFF Research Database (Denmark)

Bekö, Gabriel; Allen, Joseph G.; Weschler, Charles J.

2015-01-01

relatively low (median: 9.5 ppb). On thirteen flights (16%) ozone levels exceeded 60 ppb, while the highest peak level reached 256 ppb for a single flight. The most commonly reported symptoms were dry mouth or lips (26%), dry eyes (22.1%) and nasal stuffiness (18.9%). 46% of passengers reported at least one...... symptom related to the eyes or mouth. A third of the passengers reported at least one upper respiratory symptom. Using multivariate logistic (individual symptoms) and linear (aggregated continuous symptom variables) regression, ozone was consistently associated with symptoms related to the eyes...... and certain upper respiratory endpoints. A concentration-response relationship was observed for nasal stuffiness and eye and upper respiratory symptom indicators. Average ozone levels, as opposed to peak concentrations, exhibited slightly weaker associations. Medium and long duration flights were...

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)

Ozone depletion, related UVB changes and increased skin cancer incidence

Science.gov (United States)

Kane, R. P.

1998-03-01

Stratospheric ozone at middle latitudes shows a seasonal variation of about +/-20%, a quasi-biennial oscillation of 1-10% range and a long-term variation in which the level was almost steady up to about 1979 and declined thereafter to the present day by about 10%. These variations are expected to be reflected in solar UVB observed at the ground, but in an opposite direction. Thus UVB should have had a long-term increase of about 10-20%, which should cause an increase in skin cancer incidence of about 20-40%. Skin cancer incidence has increased all over the world, e.g. about 90% in USA during 1974-1990. It is popularly believed that this increase in skin cancer incidence is related to the recent ozone depletion. This seems to be incorrect, for two reasons. Firstly, the observed skin cancer increase is too large (90%) compared with the expected value (40%) from ozone depletion. Secondly, cancer does not develop immediately after exposure to solar UVB. The sunburns may occur within hours; but cancer development and detection may take years, even decades. Hence the observed skin cancer increase since 1974 (no data available for earlier periods) must have occurred due to exposure to solar UVB in the 1950s and 1960s, when there was no ozone depletion. Thus, the skin cancer increase must be attributed to harmful solar UVB levels existing even in the 1960s, accentuated later not by ozone depletion (which started only much later, by 1979) but by other causes, such as a longer human life span, better screening, increasing tendencies of sunbathing at beaches, etc., in affluent societies. On the other hand, the recent ozone depletion and the associated UVB increases will certainly take their toll; only that the effects will not be noticed now but years or decades from now. The concern for the future expressed in the Montreal Protocol for reducing ozone depletion by controlling CFC production is certainly justified, especially because increased UVB is harmful to animal and

A modeling study of the impact of urban trees on ozone

Science.gov (United States)

David J. Nowak; Kevin L. Civerolo; S. Trivikrama Rao; Gopal Sistla; Christopher J. Luley; Daniel E. Crane

2000-01-01

Modeling the effects of increased urban tree cover on ozone concentrations (July 13-15, 1995) from Washington, DC, to central Massachusetts reveals that urban trees generally reduce ozone concentrations in cities, but tend to increase average ozone concentrations in the overall modeling domain. During the daytime, average ozone reductions in urban areas (1 ppb) were...

Serum lipid and lipoprotein concentrations following exposure to ozone

Energy Technology Data Exchange (ETDEWEB)

Vaughan, W J; Adamson, G L; Lindgren, F T; Schooley, J.C.

1984-07-01

The effects of exposure to ozone (O/sub 3/) on concentrations of serum lipids and lipoproteins were investigated. Male and female guinea pigs were exposed to O/sub 3/ at 1 ppm for two weeks. Serum concentrations of cholesterol, triglycerides, low density (LDL) and very low density (VLDL) lipoproteins were elevated after O/sub 3/ exposure, particularly in males. During O/sub 3/ exposure the food intake per day decreased (for a constant body weight), suggesting that metabolic rate and possibly basal metabolic rate was lower. Lung wet weights increased during O/sub 3/ exposure by 87% for males and 45% for females. When individual lung weight/body weight ratios were correlated with cholesterol and LDL values from the same animal, a high correlation is found for males (r . 0.81, P less than 0.05), suggesting that there may be a relationship between lipoprotein elevations and lung damage for males. Because elevated concentrations of lipids and lipoproteins in humans increase the risk of coronary heart disease (CHD), the lipoprotein results suggest that an epidemiological study of the incidence of CHD with metropolitan O/sub 3/ levels may be warranted.

Effect of low concentrations of ozone on Escherichia coli chromosome

Energy Technology Data Exchange (ETDEWEB)

Hamelin, C; Chung, Y S

1975-01-01

The investigations reported here are an extension of previous work reported from the same laboratory, the aim of which is to demonstrate the potential of ozone to have mutagenic effects in man. Data indicate that ozone has the ability to induce mutation in a wide range of genes responsible for the nutritional properties of E. coli. They also indicate that there are a great number of mutant strains either more resistant or more sensitive to UV radiation than the parental strain; and there are numerous mucoid strains forming excessive amounts of capsular polysaccharide after treatment. It appears that ozone could be expected to produce mutation in all types of genes. Considering that these findings in the microbial system studied are associated with positive findings in in vivo cytogenetics-acute tests, and that extrapolation of mutation rates directly from experimental organisms to man can be done with confidence, it seems that even the very low concentrations of ozone which occur in certain weather conditions must be avoided. 17 references, 1 table.

Bromate formation in a hybrid ozonation-ceramic membrane filtration system.

Science.gov (United States)

Moslemi, Mohammadreza; Davies, Simon H; Masten, Susan J

2011-11-01

The effect of pH, ozone mass injection rate, initial bromide concentration, and membrane molecular weight cut off (MWCO) on bromate formation in a hybrid membrane filtration-ozonation reactor was studied. Decreasing the pH, significantly reduced bromate formation. Bromate formation increased with increasing gaseous ozone mass injection rate, due to increase in dissolved ozone concentrations. Greater initial bromide concentrations resulted in higher bromate concentrations. An increase in the bromate concentration was observed by reducing MWCO, which resulted in a concomitant increase in the retention time in the system. A model to estimate the rate of bromate formation was developed. Good correlation between the model simulation and the experimental data was achieved. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effect of low concentrations of ozone on the enzymes catalase, peroxidase, papain and urease

Energy Technology Data Exchange (ETDEWEB)

Todd, G W

1958-01-01

The enzymes catalase, peroxidase, papain and urease were treated in vitro with low concentrations of ozone gas. Wide variations were found in the sensitivity of the enzymes to the inhibitory action of the gas. Papain showed the greatest sensitivity; the rest required a much greater amount of ozone for inactivation. Comparisons of ozone and hydrogen peroxide as inhibitors of papain and urease showed ozone to be 30 times as effective as hydrogen peroxide on papain and 3 times as effective on urease. 14 references, 2 figures, 3 tables.

Mesoscale circulation systems and ozone concentrations during ESCOMPTE: a case study from IOP 2b

Science.gov (United States)

Kalthoff, N.; Kottmeier, C.; Thürauf, J.; Corsmeier, U.; Saїd, F.; Fréjafon, E.; Perros, P. E.

2005-03-01

The main objective of 'Expérience sur Site pour COntraindre les Modèles de Pollution atmosphérique et de Transport d'Emissions' (ESCOMPTE) is to generate a relevant data set for testing and evaluating mesoscale chemistry-transport models (CTMs). During ESCOMPTE, measurements have been performed at numerous surface stations, by radars and lidars, and several aircraft in the planetary boundary layer. The data from these different sources have been merged to obtain a consistent description of the spatial distribution of wind, temperature, humidity, and ozone for the photosmog episode on June 25, 2001 (IOP 2b). On this day, moderate synoptic winds favour the evolution of different mesoscale circulation systems. During daytime, the sea breeze penetrates towards the north in the Rhône valley. As the winds above the sea breeze layer come from the east, polluted air from the metropolitan area of Marseille leads to an increase of ozone at elevated layers above the convective boundary layer (CBL). At the mountainous station of Luberon about 55 km north of Marseille around noon, when the CBL top surpasses the height of the mountain summit, polluted air with ozone concentrations of about 120 ppbv arrived from southerly directions, thus indicating the passage of the city plume of Marseille. At Cadarache and Vinon in the Durance valley, about 60 km inland, the ozone maximum at the surface and at flight level 920 m MSL appears between 14 and 15 UTC. At this time, southwesterly valley winds prevail in the valley, while southerly winds occur above. This finding highlights the height-dependent advection of ozone due to interacting mesoscale circulation systems. These dynamical processes need to be represented adequately in CTMs to deliver a realistic description of the ozone concentration fields.

On the impact of temperature on tropospheric ozone concentration ...

Indian Academy of Sciences (India)

The influence of temperature on tropospheric ozone (O3)concentrations in urban and photochemically polluted areas in the greater Athens region are investigated in the present study.Hourly values of the ambient air temperature used for studying the urban heat island effect in Athens were recorded at twenty-three ...

Power consumption analysis DBD plasma ozone generator

International Nuclear Information System (INIS)

Nur, M.; Restiwijaya, M.; Muchlisin, Z.; Arianto, F.; Susan, I. A.; Widyanto, S. A.

2016-01-01

Studies on the consumption of energy by an ozone generator with various constructions electrodes of dielectric barrier discharge plasma (DBDP) reactor has been carried out. This research was done to get the configuration of the reactor, that is capable to produce high ozone concentrations with low energy consumption. BDBP reactors were constructed by spiral- cylindrical configuration, plasma ozone was generated by high voltage AC voltage up to 25 kV and maximum frequency of 23 kHz. The reactor consists of an active electrode in the form of a spiral-shaped with variation diameter Dc, and it was made by using copper wire with diameter Dw. In this research, we variated number of loops coil windings N as well as Dc and Dw. Ozone concentrations greater when the wire's diameter Dw and the diameter of the coil windings applied was greater. We found that impedance greater will minimize the concentration of ozone, in contrary to the greater capacitance will increase the concentration of ozone. The ozone concentrations increase with augmenting of power. Maximum power is effective at DBD reactor spiral-cylinder is on the Dc = 20 mm, Dw = 1.2 mm, and the number of coil windings N = 10 loops with the resulting concentration is greater than 20 ppm and it consumes energy of 177.60 watts (paper)

Regional ozone impacts of increased natural gas use in the Texas power sector and development in the Eagle Ford shale.

Science.gov (United States)

Pacsi, Adam P; Kimura, Yosuke; McGaughey, Gary; McDonald-Buller, Elena C; Allen, David T

2015-03-17

The combined emissions and air quality impacts of electricity generation in the Texas grid and natural gas production in the Eagle Ford shale were estimated at various natural gas price points for the power sector. The increased use of natural gas in the power sector, in place of coal-fired power generation, drove reductions in average daily maximum 8 h ozone concentration of 0.6-1.3 ppb in northeastern Texas for a high ozone episode used in air quality planning. The associated increase in Eagle Ford upstream oil and gas production nitrogen oxide (NOx) emissions caused an estimated local increase, in south Texas, of 0.3-0.7 ppb in the same ozone metric. In addition, the potential ozone impacts of Eagle Ford emissions on nearby urban areas were estimated. On the basis of evidence from this work and a previous study on the Barnett shale, the combined ozone impact of increased natural gas development and use in the power sector is likely to vary regionally and must be analyzed on a case by case basis.

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

The Solubility of Ozone in Deionized Water and its Cleaning Efficiency

Energy Technology Data Exchange (ETDEWEB)

Han, J.H.; Park, J.G. [Hanyang University, Seoul (Korea, Republic of); Kwak, Y.S. [Hanyang Technology Co., Ltd., Ansan (Korea, Republic of)

1998-06-01

The purpose of this study was to investigate the behavior of ozone in DI water and the reaction with wafers during the semiconductor wet cleaning process. The solubility of ozone in DI water was not only dependent on the temperature but also directly proportional to the input concentration of ozone. The lower the initial ozone concentration and the temperature, the longer the half-life time of ozone. The reaction order of ozone in DI water was calculated to be around 1.5. The redox potential reached a saturation value in 5min and slightly increased as the input ozone concentrations increased. The completely hydrophilic surface was created in 1min when HF etched silicon wafer was cleaned in ozonized DI water containing higher ozone concentrations than 2ppm. Spectroscopic ellipsometry measurements showed that the chemical oxide formed by ozonized DI water was measured to be thicker than that by piranha solution. The wafers contaminated with a non-ionic surfactant were more effectively cleaned in ozonized DI water than in piranha and ozonized piranha solutions. (author). 19 refs., 11 figs., 1 tab.

Transportable lidar for the measurement of ozone concentration and flux profiles in the lower troposphere

International Nuclear Information System (INIS)

Zhao, Yanzeng; Howell, J.N.; Hardesty, R.M.

1992-01-01

In many areas of the United States, as well as in other industrial areas (such as Europe), elevated and potentially harmful levels of ozone are being measured during summer. Most of this ozone is photochemically produced. The relatively long lifetime of ozone allows industrially produced ozone to be transported on a hemispheric scale. Since the trends of tropospheric ozone are very likely dependent on the source strengths and distributions of the pollutants and the chemical/ transport process involved, a predictive understanding of tropospheric ozone climatology requires a focus on the chemical and transport processes that link regional emissions to hemispheric ozone trends and distributions. Of critical importance to these studies is a satisfactory data base of tropospheric ozone distribution from which global and regional tropospheric ozone climatology can be derived, and the processes controlling tropospheric ozone can be better understood. A transportable lidar for measuring ozone concentration and flux profiles in the lower troposphere is needed. One such system is being developed at the National Oceanic and Atmospheric Administration/Earth Resources Laboratory (NOAA/ERL) Wave Propagation Laboratory (WPL)

Comparative scenario study of tropospheric ozone climate interactions using a global model. A 1% global increase rate, the IS92a IPCC scenario and a simplified aircraft traffic increase scenario

Energy Technology Data Exchange (ETDEWEB)

Chalita, S [Centre National de la Recherche Scientifique (CNRS), 75 - Paris (France). Service d` Aeronomie; Le Treut, H [Centre National de la Recherche Scientifique (CNRS), 75 - Paris (France). Lab. de Meteorologie Dynamique

1998-12-31

Sensitivity studies have been made to establish the relationship between different scenarios of tropospheric ozone increase and radiative forcing. Some aspects of the ozone-climate interactions for past and future scenarios are investigated. These calculations employ IMAGES tropospheric ozone concentrations for a pre-industrial, present and future atmospheres. The averaged last 10 years of the 25-year seasonal integrations were analyzed. The results of this study are preliminary. Ozone forcing is basically different from the CO{sub 2} forcing, for its regional and temporal structured nature and for its rather weak intensity. (R.P.) 14 refs.

Comparative scenario study of tropospheric ozone climate interactions using a global model. A 1% global increase rate, the IS92a IPCC scenario and a simplified aircraft traffic increase scenario

Energy Technology Data Exchange (ETDEWEB)

Chalita, S. [Centre National de la Recherche Scientifique (CNRS), 75 - Paris (France). Service d`Aeronomie; Le Treut, H. [Centre National de la Recherche Scientifique (CNRS), 75 - Paris (France). Lab. de Meteorologie Dynamique

1997-12-31

Sensitivity studies have been made to establish the relationship between different scenarios of tropospheric ozone increase and radiative forcing. Some aspects of the ozone-climate interactions for past and future scenarios are investigated. These calculations employ IMAGES tropospheric ozone concentrations for a pre-industrial, present and future atmospheres. The averaged last 10 years of the 25-year seasonal integrations were analyzed. The results of this study are preliminary. Ozone forcing is basically different from the CO{sub 2} forcing, for its regional and temporal structured nature and for its rather weak intensity. (R.P.) 14 refs.

Molecular storage of ozone in a clathrate hydrate: an attempt at preserving ozone at high concentrations.

Directory of Open Access Journals (Sweden)

Takahiro Nakajima

Full Text Available This paper reports an experimental study of the formation of a mixed O(3+ O(2+ CO(2 hydrate and its frozen storage under atmospheric pressure, which aimed to establish a hydrate-based technology for preserving ozone (O(3, a chemically unstable substance, for various industrial, medical and consumer uses. By improving the experimental technique that we recently devised for forming an O(3+ O(2+ CO(2 hydrate, we succeeded in significantly increasing the fraction of ozone contained in the hydrate. For a hydrate formed at a system pressure of 3.0 MPa, the mass fraction of ozone was initially about 0.9%; and even after a 20-day storage at -25°C and atmospheric pressure, it was still about 0.6%. These results support the prospect of establishing an economical, safe, and easy-to-handle ozone-preservation technology of practical use.

Effects of Low Ozone Concentrations and Short Exposure Times on the Mortality of Immature Stages of the Indian Meal Moth, Plodia Interpunctella (Lepidoptera: Pyralidae

Directory of Open Access Journals (Sweden)

Keivanloo Ensieh

2014-07-01

Full Text Available In Iran, the Indian meal moth, Plodia interpunctella (Hübner, is one of the most important pests of such stored products as date fruits and pistachio nuts. Ozone was applied as a gas at four concentrations (0, 2, 3, and 5 ppm for four different periods (30, 60, 90, and 120 min on the immature stages of P. interpunctella. The results indicated that by increasing the concentration and exposure time, the rate of mortality increased for all tested stages. This study showed that 12-day-old larvae were more susceptible than other stages when exposed to 5 ppm ozone for 120 min. The next in order of susceptibility were pupae, then 5-day-old larvae, and 17-dayold larvae had the highest sensitivity to ozonation. At the highest concentration of ozone, for the longest time, the least mortality rate was recorded for one-day-old eggs. According to the results, a reduction in the population density of P. interpunctella in laboratory experiments is promising. However, validation studies will be necessary to fully determine the potential of ozone as a replacement for the current post harvest chemical control of P. interpunctella on either pistachio nuts or date fruits.

Attribution of projected changes in summertime US ozone and PM2.5 concentrations to global changes

Directory of Open Access Journals (Sweden)

A. Guenther

2009-02-01

Full Text Available The impact that changes in future climate, anthropogenic US emissions, background tropospheric composition, and land-use have on summertime regional US ozone and PM2.5 concentrations is examined through a matrix of downscaled regional air quality simulations, where each set of simulations was conducted for five months of July climatology, using the Community Multi-scale Air Quality (CMAQ model. Projected regional scale changes in meteorology due to climate change under the Intergovernmental Panel on Climate Change (IPCC A2 scenario are derived through the downscaling of Parallel Climate Model (PCM output with the MM5 meteorological model. Future chemical boundary conditions are obtained through downscaling of MOZART-2 (Model for Ozone and Related Chemical Tracers, version 2.4 global chemical model simulations based on the IPCC Special Report on Emissions Scenarios (SRES A2 emissions scenario. Projected changes in US anthropogenic emissions are estimated using the EPA Economic Growth Analysis System (EGAS, and changes in land-use are projected using data from the Community Land Model (CLM and the Spatially Explicit Regional Growth Model (SERGOM. For July conditions, changes in chemical boundary conditions are found to have the largest impact (+5 ppbv on average daily maximum 8-h (DM8H ozone. Changes in US anthropogenic emissions are projected to increase average DM8H ozone by +3 ppbv. Land-use changes are projected to have a significant influence on regional air quality due to the impact these changes have on biogenic hydrocarbon emissions. When climate changes and land-use changes are considered simultaneously, the average DM8H ozone decreases due to a reduction in biogenic VOC emissions (−2.6 ppbv. Changes in average 24-h (A24-h PM2.5 concentrations are dominated by projected changes in anthropogenic emissions (+3 μg m−3, while changes in chemical boundary conditions have a negligible effect. On average, climate change reduces A24-h PM2

IMPACT OF AN OZONE GENERATOR AIR CLEANER ON STYRENE CONCENTRATIONS IN AN INDOOR AIR QUALITY RESEARCH CHAMBER

Science.gov (United States)

The paper gives results of an investigation of the impact of an ozone generator air cleaner on vapor-phase styrene concentrations in a full-scale indoor air quality test chamber. The time history of the concentrations of styrene and ozone is well predicted by a simulation model u...

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.

Case study of stratospheric ozone affecting ground-level oxidant concentrations

International Nuclear Information System (INIS)

Lamb, R.G.

1977-01-01

During the predawn hours of 19 November 1972, the air pollution monitoring station at Santa Rosa, Calif., recorded five consecutive hours of oxidant concentrations in excess of the present National Ambient Air Quality Standard. The highest of the hourly averages was 0.23 ppm. From a detailed analysis of the meteorological conditions surrounding this incident, it is shown that the ozone responsible for the anomalous concentrations originated in the stratosphere and not from anthropogenic sources

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.

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.

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.

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)

Impacts of stratospheric sulfate geoengineering on tropospheric ozone

Directory of Open Access Journals (Sweden)

L. Xia

2017-10-01

Full Text Available A range of solar radiation management (SRM techniques has been proposed to counter anthropogenic climate change. Here, we examine the potential effects of stratospheric sulfate aerosols and solar insolation reduction on tropospheric ozone and ozone at Earth's surface. Ozone is a key air pollutant, which can produce respiratory diseases and crop damage. Using a version of the Community Earth System Model from the National Center for Atmospheric Research that includes comprehensive tropospheric and stratospheric chemistry, we model both stratospheric sulfur injection and solar irradiance reduction schemes, with the aim of achieving equal levels of surface cooling relative to the Representative Concentration Pathway 6.0 scenario. This allows us to compare the impacts of sulfate aerosols and solar dimming on atmospheric ozone concentrations. Despite nearly identical global mean surface temperatures for the two SRM approaches, solar insolation reduction increases global average surface ozone concentrations, while sulfate injection decreases it. A fundamental difference between the two geoengineering schemes is the importance of heterogeneous reactions in the photochemical ozone balance with larger stratospheric sulfate abundance, resulting in increased ozone depletion in mid- and high latitudes. This reduces the net transport of stratospheric ozone into the troposphere and thus is a key driver of the overall decrease in surface ozone. At the same time, the change in stratospheric ozone alters the tropospheric photochemical environment due to enhanced ultraviolet radiation. A shared factor among both SRM scenarios is decreased chemical ozone loss due to reduced tropospheric humidity. Under insolation reduction, this is the dominant factor giving rise to the global surface ozone increase. Regionally, both surface ozone increases and decreases are found for both scenarios; that is, SRM would affect regions of the world differently in terms of air

Impacts of stratospheric sulfate geoengineering on tropospheric ozone

Science.gov (United States)

Xia, Lili; Nowack, Peer J.; Tilmes, Simone; Robock, Alan

2017-10-01

A range of solar radiation management (SRM) techniques has been proposed to counter anthropogenic climate change. Here, we examine the potential effects of stratospheric sulfate aerosols and solar insolation reduction on tropospheric ozone and ozone at Earth's surface. Ozone is a key air pollutant, which can produce respiratory diseases and crop damage. Using a version of the Community Earth System Model from the National Center for Atmospheric Research that includes comprehensive tropospheric and stratospheric chemistry, we model both stratospheric sulfur injection and solar irradiance reduction schemes, with the aim of achieving equal levels of surface cooling relative to the Representative Concentration Pathway 6.0 scenario. This allows us to compare the impacts of sulfate aerosols and solar dimming on atmospheric ozone concentrations. Despite nearly identical global mean surface temperatures for the two SRM approaches, solar insolation reduction increases global average surface ozone concentrations, while sulfate injection decreases it. A fundamental difference between the two geoengineering schemes is the importance of heterogeneous reactions in the photochemical ozone balance with larger stratospheric sulfate abundance, resulting in increased ozone depletion in mid- and high latitudes. This reduces the net transport of stratospheric ozone into the troposphere and thus is a key driver of the overall decrease in surface ozone. At the same time, the change in stratospheric ozone alters the tropospheric photochemical environment due to enhanced ultraviolet radiation. A shared factor among both SRM scenarios is decreased chemical ozone loss due to reduced tropospheric humidity. Under insolation reduction, this is the dominant factor giving rise to the global surface ozone increase. Regionally, both surface ozone increases and decreases are found for both scenarios; that is, SRM would affect regions of the world differently in terms of air pollution. In conclusion

Modeling the effects of reformulated gasoline usages on ambient concentrations of ozone and five air toxics

International Nuclear Information System (INIS)

Ligocki, M.P.; Schulhof, R.R.; Jackson, R.E.; Jimenez, M.M.; Atkinson, D.

1993-01-01

The use of reformulated gasolines to reduce motor-vehicle-related hydrocarbon emissions has been mandated by the 1990 Clean Air Act Amendments for nine severely polluted urban areas. Using a version of the Urban Airshed Model that includes explicit representation of five motor-vehicle-related air toxics, the effects of reformulated gasoline usage on ambient ozone and toxics concentrations were simulated. Simulations were conducted for two urban areas. Baltimore-Washington and Houston, for the year 1995. Additional simulation were conducted for Baltimore-Washington including winter and 1999 scenarios. In the Baltimore-Washington areas, the 1995 Federal reformulated gasoline scenario produce reductions of 1.1 percent in simulated peak ozone and 2.7 percent in the areal extent of simulated ozone exceedances. Simulated ozone reductions were much smaller in Houston. In the reformulated gasoline simulations, secondary formulation of formaldehyde and acetaldehyde was reduced, and decreases in ambient benzene and polycyclic organic matter (POM) concentrations were simulated. Larger reductions in ozone and toxics concentrations were simulated for reformulated gasolines meeting California Phase II standards than for those meeting Federal standards. The effects of reductions in motor-vehicle-related nitrogen oxides (NO x ) emissions, alone and in combination with hydrocarbon reductions, were also examined

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

Study of the superficial ozone concentrations in the atmosphere of Comunidad de Madrid using passive samplers

Directory of Open Access Journals (Sweden)

D. Galán Madruga

2001-06-01

Full Text Available The ozone is a secondary atmospheric pollutant which is generated for photochemical reactions of volatil organic compounds (VOC’s and nitrogen oxides (NOx. In Spain the ozone is a big problem as a consequence of the solar radiation to reach high levels. Exposure over a period of time to elevated ozone concentrations can cause damage in the public health and alterations in the vegetation.The aim of this study is to carry out the development and validation of a measurement method to let asses the superficial ozone levels in the Comunidad de Madrid, by identifing the zones more significants, where to measure with UV photometric monitors (automatics methods this pollutant and where the health and the vegetation can be affected. To such effect, passive samplers are used, which have glass fiber filters coated with a solution of sodium nitrite, potassium carbonate, glycerol and water. The nitrite ion in the presence of ozone is oxidized to nitrato ion, which it is extrated with ultrapure water and analyzed for ion chromatography, by seen proportional to the concentration existing in the sampling point.The results of validation from field tests indicate a excellent correlation between the passive and the automatic method.The higher superficial ozone concentrations are placed in rural zones, distanced of emission focus of primary pollutants (nitrogen oxides and volatil organic compounds... principally in direction soutwest and northwest of the Comunidad of Madrid.

Evaluation and Comparison of Chemiluminescence and UV Photometric Methods for Measuring Ozone Concentrations in Ambient Air

Science.gov (United States)

The current Federal Reference Method (FRM) for measuring concentrations of ozone in ambient air is based on the dry, gas-phase, chemiluminescence reaction between ethylene (C2H4) and any ozone (O3) that may be p...

Decolorization of industrial wastewater by ozonation followed by adsorption on activated carbon

International Nuclear Information System (INIS)

Konsowa, A.H.; Ossman, M.E.; Chen, Yongsheng; Crittenden, John C.

2010-01-01

The decolorization of industrial wastewater containing direct dye (Drimarene Red CL-3B) by advanced oxidation process using ozonation in a semi-batch bubble column reactor followed by granule activated carbon (GAC) adsorption process was studied. The effect of initial dye concentration, ozone concentration, pH and ozone-air flow rate on the rate of dye decolorization were investigated. It was found that the rate of dye decolorization increases with increasing ozone concentration, ozone-air flow rate, and pH but decreases with increasing initial dye concentration. This study is a hybrid system conducted in combination between ozonation process and GAC adsorption to reveal higher and efficient removal of color and TOC. The process started with ozonation for efficient and rapid decolorization of dyeing wastewater, followed by GAC adsorption process to gain efficient removal of color and TOC. The adsorption process was found to be very efficient in removal of ozonation residual TOC, in view of high TOC removal, up to 37% TOC removal was obtained. Numerical correlation using regression analysis for decolorization time with the operating conditions of the ozonation process were presented.

Decolorization of malachite green, decolorization kinetics and stoichiometry of ozone-malachite green and removal of antibacterial activity with ozonation processes

International Nuclear Information System (INIS)

Kusvuran, Erdal; Gulnaz, Osman; Samil, Ali; Yildirim, Ozlem

2011-01-01

This study aimed to identify degradation intermediates and to investigate the stoichiometry of decolorization and degradation, decolorization kinetics, and removal of antibacterial activity of malachite green (MG) using ozonization processes. The decolorization of MG was optimal at an acidic pH value of 3 based on molecular ozone attack on MG molecules. The stoichiometric ratio of decolorization between ozone and MG was calculated to be 7.0 with a regression coefficient of 0.995, whereas the ratio for degradation was calculated as 13.1 with a regression coefficient of 0.998. With MG concentrations in the range of 0.30-1.82 mM, the concentration of decolorized MG increased with higher initial concentrations of MG, whereas the ozonolytic decolorization rates of MG, decreased with increasing initial concentration. The pseudo-first-order degradation rate constants (k') decreased with the initial concentration and ranged from 0.769 to 0.223 min -1 . Twelve different intermediates were produced during the ozonation of MG with ozonation times between 5 min and 30 min and were identified by GC-MS. Although 86% of MG in the reaction mixture was removed by ozonation after 10 min, the decrease of antibacterial activity was very low (10%) for Bacillus subtilis and Staphylococcus epidermidis because the degradation intermediates, phenol and benzoic acid, also have antibacterial activity. The antibacterial activity of both MG and its intermediates were removed successfully with ozonation times above 26 min.

Decolorization of malachite green, decolorization kinetics and stoichiometry of ozone-malachite green and removal of antibacterial activity with ozonation processes

Energy Technology Data Exchange (ETDEWEB)

Kusvuran, Erdal, E-mail: erdalkusvuran@yahoo.com [Chemistry Department, Arts and Sciences Faculty, Cukurova University, 01330 Balcali, Adana (Turkey); Gulnaz, Osman [Biology Department, Arts and Sciences Faculty, Cukurova University, 01330 Balcali, Adana (Turkey); Samil, Ali [Chemistry Department, Arts and Sciences Faculty, Sutcu Imam University, 46100 Kahramanmaras (Turkey); Yildirim, Ozlem [Chemistry Department, Arts and Sciences Faculty, Cukurova University, 01330 Balcali, Adana (Turkey)

2011-02-15

This study aimed to identify degradation intermediates and to investigate the stoichiometry of decolorization and degradation, decolorization kinetics, and removal of antibacterial activity of malachite green (MG) using ozonization processes. The decolorization of MG was optimal at an acidic pH value of 3 based on molecular ozone attack on MG molecules. The stoichiometric ratio of decolorization between ozone and MG was calculated to be 7.0 with a regression coefficient of 0.995, whereas the ratio for degradation was calculated as 13.1 with a regression coefficient of 0.998. With MG concentrations in the range of 0.30-1.82 mM, the concentration of decolorized MG increased with higher initial concentrations of MG, whereas the ozonolytic decolorization rates of MG, decreased with increasing initial concentration. The pseudo-first-order degradation rate constants (k') decreased with the initial concentration and ranged from 0.769 to 0.223 min{sup -1}. Twelve different intermediates were produced during the ozonation of MG with ozonation times between 5 min and 30 min and were identified by GC-MS. Although 86% of MG in the reaction mixture was removed by ozonation after 10 min, the decrease of antibacterial activity was very low (10%) for Bacillus subtilis and Staphylococcus epidermidis because the degradation intermediates, phenol and benzoic acid, also have antibacterial activity. The antibacterial activity of both MG and its intermediates were removed successfully with ozonation times above 26 min.

Ozone and nitrogen oxides in surface air in Russia: TROICA experiments.

Science.gov (United States)

Pankratova, N.; Elansky, N.; Belikov, I.; Shumskiy, R.

2009-04-01

The results of measurements of surface ozone and nitrogen oxides concentrations over the continental regions of Russia are discussed. The measurements were done during 10 TROICA experiments (Transcontinental Observations Into the Chemistry of the Atmosphere). The TROICA experiment started in 1995. By the present moment ten expeditions along the Trans-Siberian railroad from Moscow to Vladivostok (around 9300 km) are carried out. We separate data sets into unpolluted and polluted areas to study temporal and spatial features. Moreover we analyzed cities (more then 100 cities). About 50% of all data corresponds to unpolluted conditions. The data collected are used in an analysis of the physical and chemical processes occurring over continental Russia. In this work the estimations of seasonal and daily ozone and NOx distribution were made. The seasonal distribution of ozone for TROICA experiments concentration considerably differs from ozone distribution at Mace Head (Ireland) and Hohenpeissenberg (Germany) stations and well agrees with the ozone distribution at Zotino (Russia, East Siberia). The same concerns also a daily variability. The ozone concentration gradient is presented. Ozone concentration gradually increases in the eastward direction. Its result of the air transport from polluted regions of Europe and ozone depletions, oxidations of CH4 in Siberia, forest fires in Siberia and around Baikal Lake, regional transport of burning products from Northern China. Significant factor of ozone increasing is stratospheric-tropospheric exchange. It appears in TROICA-3 experiment. During several hours ozone concentration was more then 60 ppbv. The areas of photochemical ozone generation in polluted air are also detected. We estimate anthropogenic and natural factors, which are responsible for sharp ozone concentration increasing. Acknowledgments. The work was supported by International Science and Technology Center (ISTC) under contract No. 2770 and by Russian Basic

Dependence of the degree of antibacterial and antiphage action of ozone on cell and phage particle concentrations in nutrient media

Energy Technology Data Exchange (ETDEWEB)

Grits, N.V.; Fomichev, A.Iu.

1985-05-01

The work was aimed at studying the inactivating effect of ozone on Escherichia coli K-12 AB1157, Pseudomonas aeruginosa PA01, Erwinia herbicola EH103 and their phages T4, SM and I4. The degree of bacterial and phage inactivation was found to increase with a decrease in their initial concentration during the treatment. The effect depends on differences in the quantity of ozone per cell or per phage particle in the reaction medium. This conclusion is based on the fact that, irrespective of the suspension density, the amount of surviving bacteria and phages plotted versus O3 concentration and recalculated per one bacterial cell or phage particle is described graphically by one and the same curve typical of a strain under study. This technique for assessing the sensitivity of microbiological objects to ozone can be used in order to compare experimental data obtained in different laboratories.

Enhanced effect of suction-cavitation on the ozonation of phenol

International Nuclear Information System (INIS)

Wu Zhilin; Franke, Marcus; Ondruschka, Bernd; Zhang, Yongchun; Ren Yanze; Braeutigam, Patrick; Wang, Weimin

2011-01-01

800 mL of 1.0 mM phenol-containing aqueous solution was circulated at 20 ° C for 30 min in a suction-reactor, while 3.2 mg min -1 ozone was introduced into the solution under the suction orifice. The removal rates of phenol vary polynomially with the orifice diameter as well as the suction pressure. The rate constant for the zero-order kinetics achieves the highest value at -0.070 MPa by using 5 mm orifice. Although the suction-cavitation alone cannot remove phenol in 30 min, it can considerably enhance the ozonation of phenol. The rate constants for the zero-order kinetics by the simple ozonation and the combined method are 0.018 and 0.028 min -1 , respectively. Furthermore, no ozone was observed in the tail gas during the first 15 min for the ozonation in the suction reactor, and then the concentration of unreacted ozone slowly increased, indicating that the utilization rate of ozone is significantly improved by the suction-cavitation. The increasing input concentration of ozone obviously accelerates the ozonation of phenol, but the total required quantities of ozone are very close by various ozone input concentrations to reach the same degradation rate, indicating the ozonation assisted by the suction-cavitation can be considered as a quantitative reaction.

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

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

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.

Spatial assessment of PM{sub 10} and ozone concentrations in Europe (2005)

Energy Technology Data Exchange (ETDEWEB)

2009-07-01

This report presents particulate matter (PM{sub 10}) and ground.level ozone concentration maps covering the whole of Europe. The interpolated maps are based on a combination of measurement and regional modelling results. Using measured concentrations as a primary source of information, the report summarizes the methodologies and the methodological choices taken in order to derive such maps. (au)

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...

Increased CCL24/eotaxin-2 with postnatal ozone exposure in allergen-sensitized infant monkeys is not associated with recruitment of eosinophils to airway mucosa

International Nuclear Information System (INIS)

Chou, Debbie L.; Gerriets, Joan E.; Schelegle, Edward S.; Hyde, Dallas M.; Miller, Lisa A.

2011-01-01

Epidemiology supports a causal link between air pollutant exposure and childhood asthma, but the mechanisms are unknown. We have previously reported that ozone exposure can alter the anatomic distribution of CD25+ lymphocytes in airways of allergen-sensitized infant rhesus monkeys. Here, we hypothesized that ozone may also affect eosinophil trafficking to allergen-sensitized infant airways. To test this hypothesis, we measured blood, lavage, and airway mucosa eosinophils in 3-month old monkeys following cyclical ozone and house dust mite (HDM) aerosol exposures. We also determined if eotaxin family members (CCL11, CCL24, CCL26) are associated with eosinophil location in response to exposures. In lavage, eosinophil numbers increased in animals exposed to ozone and/or HDM. Ozone + HDM animals showed significantly increased CCL24 and CCL26 protein in lavage, but the concentration of CCL11, CCL24, and CCL26 was independent of eosinophil number for all exposure groups. In airway mucosa, eosinophils increased with exposure to HDM alone; comparatively, ozone and ozone + HDM resulted in reduced eosinophils. CCL26 mRNA and immunofluorescence staining increased in airway mucosa of HDM alone animals and correlated with eosinophil volume. In ozone + HDM animal groups, CCL24 mRNA and immunofluorescence increased along with CCR3 mRNA, but did not correlate with airway mucosa eosinophils. Cumulatively, our data indicate that ozone exposure results in a profile of airway eosinophil migration that is distinct from HDM mediated pathways. CCL24 was found to be induced only by combined ozone and HDM exposure, however expression was not associated with the presence of eosinophils within the airway mucosa. -- Highlights: ► Ozone can modulate the localization of eosinophils in infant allergic airways. ► Expression of eotaxins within the lung is affected by ozone and allergen exposure. ► CCL24 induction by ozone and allergen exposure is not linked to eosinophilia.

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

Ozone depletion following future volcanic eruptions

Science.gov (United States)

Eric Klobas, J.; Wilmouth, David M.; Weisenstein, Debra K.; Anderson, James G.; Salawitch, Ross J.

2017-07-01

While explosive volcanic eruptions cause ozone loss in the current atmosphere due to an enhancement in the availability of reactive chlorine following the stratospheric injection of sulfur, future eruptions are expected to increase total column ozone as halogen loading approaches preindustrial levels. The timing of this shift in the impact of major volcanic eruptions on the thickness of the ozone layer is poorly known. Modeling four possible climate futures, we show that scenarios with the smallest increase in greenhouse gas concentrations lead to the greatest risk to ozone from heterogeneous chemical processing following future eruptions. We also show that the presence in the stratosphere of bromine from natural, very short-lived biogenic compounds is critically important for determining whether future eruptions will lead to ozone depletion. If volcanic eruptions inject hydrogen halides into the stratosphere, an effect not considered in current ozone assessments, potentially profound reductions in column ozone would result.

Issues in Stratospheric Ozone Depletion.

Science.gov (United States)

Lloyd, Steven Andrew

Following the announcement of the discovery of the Antarctic ozone hole in 1985 there have arisen a multitude of questions pertaining to the nature and consequences of polar ozone depletion. This thesis addresses several of these specific questions, using both computer models of chemical kinetics and the Earth's radiation field as well as laboratory kinetic experiments. A coupled chemical kinetic-radiative numerical model was developed to assist in the analysis of in situ field measurements of several radical and neutral species in the polar and mid-latitude lower stratosphere. Modeling was used in the analysis of enhanced polar ClO, mid-latitude diurnal variation of ClO, and simultaneous measurements of OH, HO_2, H_2 O and O_3. Most importantly, such modeling was instrumental in establishing the link between the observed ClO and BrO concentrations in the Antarctic polar vortex and the observed rate of ozone depletion. The principal medical concern of stratospheric ozone depletion is that ozone loss will lead to the enhancement of ground-level UV-B radiation. Global ozone climatology (40^circS to 50^ circN latitude) was incorporated into a radiation field model to calculate the biologically accumulated dosage (BAD) of UV-B radiation, integrated over days, months, and years. The slope of the annual BAD as a function of latitude was found to correspond to epidemiological data for non-melanoma skin cancers for 30^circ -50^circN. Various ozone loss scenarios were investigated. It was found that a small ozone loss in the tropics can provide as much additional biologically effective UV-B as a much larger ozone loss at higher latitudes. Also, for ozone depletions of > 5%, the BAD of UV-B increases exponentially with decreasing ozone levels. An important key player in determining whether polar ozone depletion can propagate into the populated mid-latitudes is chlorine nitrate, ClONO_2 . As yet this molecule is only indirectly accounted for in computer models and field

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

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

Study on the Ozonation of Organic Wastes (1)

Energy Technology Data Exchange (ETDEWEB)

Kim, Ki Hong; Kang, Il Sik; Hong, Dae Seok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-05-15

Ozone is often used in combination with H{sub 2}O{sub 2}, UV, peroxides, and the catalyst. These combined processes have the purpose to increase OH radicals, so this combination process is called the advanced oxidation process (AOP, Advanced Oxidation Process). In this study, the possibility of the oxidation treatment of LSC Cocktail solution by using a combination of ozone and hydrogen peroxide was investigated. The addition of a suitable amount of hydrogen peroxide increases the efficiency of the oxidation process during ozonation of the organic materials. But on the contrary, the excess addition of hydrogen they can play a role as a scavenger consuming the hydroxyl radicals generated during the ozonation process. So it is very important to find the amount of volume of hydrogen peroxide. The efficiency of oxidation treatment of organic materials is greatly depended on the properties of liquid waste (pH, concentration and chemical type of organics), the process temperature, the flow rate (waste and ozone gas), the ozone concentration, the hydrogen peroxide concentration and the presence or absence of scavengers. In this study, by using an ozone contactor (hydrophobic hollow fiber membrane type), the basic experiments were carried out to evaluate the applicability of ozonation to the organic wastes. First of all, the oxidation treatment was evaluated by ozone alone, and secondly was evaluated according to the changes of the amount of hydrogen peroxide and a pH of wastes.

Study on the Ozonation of Organic Wastes (1)

International Nuclear Information System (INIS)

Kim, Ki Hong; Kang, Il Sik; Hong, Dae Seok

2014-01-01

Ozone is often used in combination with H 2 O 2 , UV, peroxides, and the catalyst. These combined processes have the purpose to increase OH radicals, so this combination process is called the advanced oxidation process (AOP, Advanced Oxidation Process). In this study, the possibility of the oxidation treatment of LSC Cocktail solution by using a combination of ozone and hydrogen peroxide was investigated. The addition of a suitable amount of hydrogen peroxide increases the efficiency of the oxidation process during ozonation of the organic materials. But on the contrary, the excess addition of hydrogen they can play a role as a scavenger consuming the hydroxyl radicals generated during the ozonation process. So it is very important to find the amount of volume of hydrogen peroxide. The efficiency of oxidation treatment of organic materials is greatly depended on the properties of liquid waste (pH, concentration and chemical type of organics), the process temperature, the flow rate (waste and ozone gas), the ozone concentration, the hydrogen peroxide concentration and the presence or absence of scavengers. In this study, by using an ozone contactor (hydrophobic hollow fiber membrane type), the basic experiments were carried out to evaluate the applicability of ozonation to the organic wastes. First of all, the oxidation treatment was evaluated by ozone alone, and secondly was evaluated according to the changes of the amount of hydrogen peroxide and a pH of wastes

Study nonlinear dynamics of stratospheric ozone concentration at Pakistan Terrestrial region

Science.gov (United States)

Jan, Bulbul; Zai, Muhammad Ayub Khan Yousuf; Afradi, Faisal Khan; Aziz, Zohaib

2018-03-01

This study investigates the nonlinear dynamics of the stratospheric ozone layer at Pakistan atmospheric region. Ozone considered now the most important issue in the world because of its diverse effects on earth biosphere, including human health, ecosystem, marine life, agriculture yield and climate change. Therefore, this paper deals with total monthly time series data of stratospheric ozone over the Pakistan atmospheric region from 1970 to 2013. Two approaches, basic statistical analysis and Fractal dimension (D) have adapted to study the nature of nonlinear dynamics of stratospheric ozone level. Results obtained from this research have shown that the Hurst exponent values of both methods of fractal dimension revealed an anti-persistent behavior (negatively correlated), i.e. decreasing trend for all lags and Rescaled range analysis is more appropriate as compared to Detrended fluctuation analysis. For seasonal time series all month follows an anti-persistent behavior except in the month of November which shown persistence behavior i.e. time series is an independent and increasing trend. The normality test statistics also confirmed the nonlinear behavior of ozone and the rejection of hypothesis indicates the strong evidence of the complexity of data. This study will be useful to the researchers working in the same field in the future to verify the complex nature of stratospheric ozone.

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.

Trends in Pinus ponderosa foliar pigment concentration due to chronic exposure of ozone and acid rain

International Nuclear Information System (INIS)

Neuman, L.; Houpis, J.; Anderson, P.

1991-01-01

To determine the effects of ozone and acid rain on mature Ponderosa pine trees, Lawrence Livermore National Lab. has collaborated with University of California Berkeley, University of California Davis, California State University Chico, and the US Forest Service at the latter's Chico Tree Improvement Center. Foliar tissue from mature grafted scions of Pinus ponderosa were exposed to two times ambient ozone for ten months and to acid rain (3.0 pH) weekly for 10 weeks using branch exposure chambers. Pigment extracts were analyzed spectrophotometrically for concentrations of chlorophylls a and b, and carotenoid pigments, at 662 nm, 644 nm, and 470 nm, respectively. Pigment concentrations were expressed on a surface area basis. Preliminary results revealed that chlorophyll a showed a downward trend due to the ozone treatment. Acid rain caused no effects on these three pigments, however, chlorophyll b showed an upward trend due to the interaction of ozone and acid rain. The carotenoid pigments showed no changes due to the treatments either singly, or in combination

Modelling Distribution Function of Surface Ozone Concentration for Selected Suburban Areas in Malaysia

International Nuclear Information System (INIS)

Muhammad Izwan Zariq Mokhtar; Nurul Adyani Ghazali; Muhammad Yazid Nasir; Norhazlina Suhaimi

2016-01-01

Ozone is known as an important secondary pollutant in the atmosphere. The aim of this study is to find the best fit distribution for calculating exceedance and return period of ozone based on suburban areas; Perak (AMS1) and Pulau Pinang (AMS2). Three distributions namely Gamma, Rayleigh and Laplace were used to fit 2 years ozone data (2010 and 2011). The parameters were estimated by using Maximum Likelihood Estimation (MLE) in order to plot probability distribution function (PDF) and cumulative distribution function (CDF). Four performance indicators were used to find the best distribution namely, normalized absolute error (NAE), prediction accuracy (PA), coefficient of determination (R 2 ) and root mean square error (RMSE). The best distribution to represent ozone concentration at both sites in 2010 and 2011 is Gamma distribution with the smallest error measure (NAE and RMSE) and the highest adequacy measure (PA and R 2 ). For the 2010 data, AMS1 was predicted to exceed 0.1 ppm for 2 days in 2011 with a return period of one occurrence. (author)

Effects of chronic elevated ozone concentration on the redox state and fruit yield of red pepper plant Capsicum baccatum.

Science.gov (United States)

Bortolin, Rafael Calixto; Caregnato, Fernanda Freitas; Divan, Armando Molina; Reginatto, Flávio Henrique; Gelain, Daniel Pens; Moreira, José Cláudio Fonseca

2014-02-01

Ozone (O3) is one of the most harmful air pollutants to crops, contributing to high losses on crop yield. Tropospheric O3 background concentrations have increased since pre-industrial times reaching phytotoxic concentrations in many world regions. Capsicum peppers are the second most traded spice in the world, but few studies concerning the O3 effects in this genus are known. Thereby, the aim of this work was to evaluate the effects of chronic exposure to elevated O3 concentrations in red pepper plant Capsicum baccatum L. var. pendulum with especial considerations on the leaf redox state and fruit yield. Fifteen C. baccatum plants were exposed to O3 in open-top chambers during fruit ripening (62 days) at a mean concentration of 171.6 µg/m(3) from 10:00 am to 4:00 pm. We found that O3 treated plants significantly decreased the amount and the total weight of fruits, which were probably a consequence of the changes on leaf oxidative status induced by ozone exposure. Ozone exposed plants increased the reactive oxygen species (ROS) levels on the leaves, which may be associated with the observed decrease on the activity of enzymatic antioxidant defense system, as well with lower levels of polyphenol and reduced thiol groups. Enhanced ROS production and the direct O3 reaction lead to biomacromolecules damages as seen in the diminished chlorophyll content and in the elevated lipid peroxidation and protein carbonylation levels. Through a correlation analysis it was possible to observe that polyphenols content was more important to protect pepper plants against oxidative damages to lipids than to proteins. © 2013 Published by Elsevier Inc.

Increased CCL24/eotaxin-2 with postnatal ozone exposure in allergen-sensitized infant monkeys is not associated with recruitment of eosinophils to airway mucosa

Energy Technology Data Exchange (ETDEWEB)

Chou, Debbie L.; Gerriets, Joan E. [California National Primate Research Center, UC Davis, Davis, CA 95616 (United States); Schelegle, Edward S.; Hyde, Dallas M. [California National Primate Research Center, UC Davis, Davis, CA 95616 (United States); Department of Anatomy, Physiology, and Cell Biology, UC Davis School of Veterinary Medicine, Davis, CA 95616 (United States); Miller, Lisa A., E-mail: lmiller@ucdavis.edu [California National Primate Research Center, UC Davis, Davis, CA 95616 (United States); Department of Anatomy, Physiology, and Cell Biology, UC Davis School of Veterinary Medicine, Davis, CA 95616 (United States)

2011-12-15

Epidemiology supports a causal link between air pollutant exposure and childhood asthma, but the mechanisms are unknown. We have previously reported that ozone exposure can alter the anatomic distribution of CD25+ lymphocytes in airways of allergen-sensitized infant rhesus monkeys. Here, we hypothesized that ozone may also affect eosinophil trafficking to allergen-sensitized infant airways. To test this hypothesis, we measured blood, lavage, and airway mucosa eosinophils in 3-month old monkeys following cyclical ozone and house dust mite (HDM) aerosol exposures. We also determined if eotaxin family members (CCL11, CCL24, CCL26) are associated with eosinophil location in response to exposures. In lavage, eosinophil numbers increased in animals exposed to ozone and/or HDM. Ozone + HDM animals showed significantly increased CCL24 and CCL26 protein in lavage, but the concentration of CCL11, CCL24, and CCL26 was independent of eosinophil number for all exposure groups. In airway mucosa, eosinophils increased with exposure to HDM alone; comparatively, ozone and ozone + HDM resulted in reduced eosinophils. CCL26 mRNA and immunofluorescence staining increased in airway mucosa of HDM alone animals and correlated with eosinophil volume. In ozone + HDM animal groups, CCL24 mRNA and immunofluorescence increased along with CCR3 mRNA, but did not correlate with airway mucosa eosinophils. Cumulatively, our data indicate that ozone exposure results in a profile of airway eosinophil migration that is distinct from HDM mediated pathways. CCL24 was found to be induced only by combined ozone and HDM exposure, however expression was not associated with the presence of eosinophils within the airway mucosa. -- Highlights: Black-Right-Pointing-Pointer Ozone can modulate the localization of eosinophils in infant allergic airways. Black-Right-Pointing-Pointer Expression of eotaxins within the lung is affected by ozone and allergen exposure. Black-Right-Pointing-Pointer CCL24 induction by

Inactivation of E-coli O157 : H7 in apple cider by ozone at various temperatures and concentrations

DEFF Research Database (Denmark)

Steenstrup, Lotte Dock

2004-01-01

of dissolved ozone of about 5-6 mg/L at 20C, before the on-set of E. coli O157:H7 inactivation in the cider. Total processing times, based on lag time plus 5D, ranged from about 4 to 14 min depending on temperature and ozone concentration. Overall, inactivation of E. coli O157:H7by ozone was fast enough...

Changes in gas exchange characteristics during the life span of giant sequoia: Implications for response to current and future concentrations of atmospheric ozone

Energy Technology Data Exchange (ETDEWEB)

Grulke, N.E.; Miller, P.R. (USDA Forest Service, Riverside, CA (United States))

Native stands of giant sequoia are being exposed to relatively high concentrations of atmospheric ozone produced in urban and agricultural areas upwind. The expected change in environmental conditions over the next 100 y is likely to be unprecendented in the life span (ca 2,500 y) of giant sequoia. Changes in the physiological responses of three age classes of giant sequoia (current year, 12 y and 25 y) to different concentrations of ozone were determined, and age-related differences in sensitivity to pollutants were assessed by examining physiological changes (gas exchange, water use efficiency) across the life span of giant sequoia. The CO[sub 2] exchange rate (CER) was greater in current year (12.1 [mu]mol CO[sub 2]/m[sup 2]s) and 2 year old seedlings (4.8 [mu]mol CO[sub 2]/m[sup 2]s) than in all older trees (average of 3.0 [mu]mol CO[sub 2]/m[sup 2]s). Dark respiration was highest for current year seedlings and was increased twofold in symptotic individuals exposed to elevated ozone concentrations. Stomatal conductance was greater in current-year and 2 year old seedlings (335 and 200 mmol H[sub 2]O/m[sup 2]s), respectively, than in all older trees (50 mmol H[sub 2]O/m[sup 2]s), indicating that the ozone concentration in substomatol cavities is higher in young seedlings than in older trees. Significant changes in water use efficiency occurred in trees between ages 5 and 20 years. It is concluded that giant sequoia seedlings are sensitive to atmospheric ozone until they are ca 5 y old. Low conductance, high water use efficiency, and compact mesophyll all contribute to a natural ozone tolerance, or defense, or both, in foliage of older trees. 11 refs., 1 fig., 1 tab.

Exposure of Norway spruce to ozone increases the sensitivity of current year needles to photoinhibition and desiccation

DEFF Research Database (Denmark)

Mikkelsen, Teis Nørgaard; Ro-Poulsen, H.

1994-01-01

decreases in net photosynthesis and chlorophyll fluorescence (FN/FM) were found during periods with co-occurrence of high ozone concentrations And high light intensities, indicating interactions between effects of ozone and photoinhibition. After termination of fumigation enhanced rates of photosynthesis...

DC corona discharge ozone production enhanced by magnetic field

Science.gov (United States)

Pekárek, S.

2010-01-01

We have studied the effect of a stationary magnetic field on the production of ozone from air at atmospheric pressure by a negative corona discharge in a cylindrical electrode configuration. We used a stainless steel hollow needle placed at the axis of the cylindrical discharge chamber as a cathode. The outer wall of the cylinder was used as an anode. The vector of magnetic induction was perpendicular to the vector of current density. We found that: (a) the magnetic field extends the current voltage range of the discharge; (b) for the discharge in the Trichel pulses regime and in the pulseless glow regime, the magnetic field has no substantial effect on the discharge voltage or on the concentration of ozone that is produced; (c) for the discharge in the filamentary streamer regime for a particular current, the magnetic field increases the discharge voltage and consequently an approximately 30% higher ozone concentration can be obtained; (d) the magnetic field does not substantially increase the maximum ozone production yield. A major advantage of using a magnetic field is that the increase in ozone concentration produced by the discharge can be obtained without additional energy requirements.

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.

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....

Urban Ozone Concentration Forecasting with Artificial Neural Network in Corsica

Directory of Open Access Journals (Sweden)

Tamas Wani

2014-03-01

Full Text Available Atmospheric pollutants concentration forecasting is an important issue in air quality monitoring. Qualitair Corse, the organization responsible for monitoring air quality in Corsica (France, needs to develop a short-term prediction model to lead its mission of information towards the public. Various deterministic models exist for local forecasting, but need important computing resources, a good knowledge of atmospheric processes and can be inaccurate because of local climatical or geographical particularities, as observed in Corsica, a mountainous island located in the Mediterranean Sea. As a result, we focus in this study on statistical models, and particularly Artificial Neural Networks (ANNs that have shown good results in the prediction of ozone concentration one hour ahead with data measured locally. The purpose of this study is to build a predictor realizing predictions of ozone 24 hours ahead in Corsica in order to be able to anticipate pollution peaks formation and to take appropriate preventive measures. Specific meteorological conditions are known to lead to particular pollution event in Corsica (e.g. Saharan dust events. Therefore, an ANN model will be used with pollutant and meteorological data for operational forecasting. Index of agreement of this model was calculated with a one year test dataset and reached 0.88.

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.

Ozone and the oxidizing properties of the troposphere

International Nuclear Information System (INIS)

Megie, G.

1996-01-01

This article is about the rising concentration of ozone and photo-oxidizers observed in the troposphere, the atmosphere between the ground and a height of 10 to 15 km. This serious global environmental problem has up to now been less well known than the greenhouse effect or the decrease in stratospheric ozone. This is because it varies with time and place and involves many complicated physico-chemical and atmospheric processes. At our latitudes, the average ozone concentration in the air we breathe has quadrupled since the beginning of this century. In polluted areas it often exceeds the recommended norms. This increase in ozone concentrations in the lower atmosphere directly reflects the impact of man-made emissions of compounds like methane, carbon monoxide, hydrocarbons and nitrogen oxides. Sunlight acts on these compounds to form ozone via complicated chemical reactions. This change in oxidizing properties of the troposphere is beginning produce perceptible effects on vegetable production, human health and climate. (author). 24 refs., 5 figs., 4 tabs

Influence of Ar addition on ozone generation in a non-thermal plasma—a numerical investigation

Science.gov (United States)

Chen, Hsin Liang; Lee, How Ming; Chen, Shiaw Huei; Wei, Ta Chin; Been Chang, Moo

2010-10-01

A numerical model based on a dielectric barrier discharge is developed in this study to investigate the influence of Ar addition on ozone generation. The simulation results show good agreement with the experimental data, confirming the validity of the numerical model. The mechanisms regarding how the Ar addition affects ozone generation are investigated with the assistance of a numerical simulation by probing into the following two questions, (1) why the ozone concentration just slightly decreases in the low specific input energy (SIE, the ratio of discharge power to gas flow rate) region even if the inlet O2 concentration is substantially decreased and (2) why the variation of the increased rate of ozone concentration with SIE (i.e. the variation in the slope of ozone concentration versus SIE) is more significant for an O2/Ar mixture plasma. As SIE is relatively low, ozone decomposition through electron-impact and radical attack reactions is less significant because of low ozone concentration and gas temperature. Therefore, the ozone concentration depends mainly on the amount of oxygen atoms generated. The simulation results indicate that the amount of oxygen atoms generated per electronvolt for Ar concentrations of 0%, 10%, 30%, 50% and 80% are 0.178, 0.174, 0.169, 0.165 and 0.166, respectively, explaining why the ozone concentration does not decrease linearly with the inlet O2 concentration in the low SIE region. On the other hand, the simulation results show that increasing Ar concentration would lead to a lower reduced field and a higher gas temperature. The former would lead to an increase in the rate constant of e + O3 → e + O + O2 while the latter would result in a decrease in the rate constant of O + O2 + M → O3 + M and an increase in that of O3 + O → 2O2. The changes in the rate constants of these reactions would have a negative effect on ozone generation, which is the rationale for the second question.

Influence of Ar addition on ozone generation in a non-thermal plasma-a numerical investigation

International Nuclear Information System (INIS)

Chen, Hsin Liang; Lee, How Ming; Chen, Shiaw Huei; Wei, Ta Chin; Chang, Moo Been

2010-01-01

A numerical model based on a dielectric barrier discharge is developed in this study to investigate the influence of Ar addition on ozone generation. The simulation results show good agreement with the experimental data, confirming the validity of the numerical model. The mechanisms regarding how the Ar addition affects ozone generation are investigated with the assistance of a numerical simulation by probing into the following two questions, (1) why the ozone concentration just slightly decreases in the low specific input energy (SIE, the ratio of discharge power to gas flow rate) region even if the inlet O 2 concentration is substantially decreased and (2) why the variation of the increased rate of ozone concentration with SIE (i.e. the variation in the slope of ozone concentration versus SIE) is more significant for an O 2 /Ar mixture plasma. As SIE is relatively low, ozone decomposition through electron-impact and radical attack reactions is less significant because of low ozone concentration and gas temperature. Therefore, the ozone concentration depends mainly on the amount of oxygen atoms generated. The simulation results indicate that the amount of oxygen atoms generated per electronvolt for Ar concentrations of 0%, 10%, 30%, 50% and 80% are 0.178, 0.174, 0.169, 0.165 and 0.166, respectively, explaining why the ozone concentration does not decrease linearly with the inlet O 2 concentration in the low SIE region. On the other hand, the simulation results show that increasing Ar concentration would lead to a lower reduced field and a higher gas temperature. The former would lead to an increase in the rate constant of e + O 3 → e + O + O 2 while the latter would result in a decrease in the rate constant of O + O 2 + M → O 3 + M and an increase in that of O 3 + O → 2O 2 . The changes in the rate constants of these reactions would have a negative effect on ozone generation, which is the rationale for the second question.

Aerosol-ozone correlations during dust transport episodes

Directory of Open Access Journals (Sweden)

P. Bonasoni

2004-01-01

Full Text Available Its location in the Mediterranean region and its physical characteristics render Mt. Cimone (44°11′ N, 10°42′ E, the highest peak of the Italian northern Apennines (2165 m asl, particularly suitable to study the transport of air masses from the north African desert area to Europe. During these northward transports 12 dust events were registered in measurements of the aerosol concentration at the station during the period June–December 2000, allowing the study of the impact of mineral dust transports on free tropospheric ozone concentrations, which were also measured at Mt. Cimone. Three-dimensional backward trajectories were used to determine the air mass origin, while TOMS Aerosol Index data for the Mt. Cimone area were used to confirm the presence of absorbing aerosol over the measurement site. A trajectory statistical analysis allowed identifying the main source areas of ozone and aerosols. The analysis of these back trajectories showed that central Europe and north and central Italy are the major pollution source areas for ozone and fine aerosol, whereas the north African desert regions were the most important source areas for coarse aerosol and low ozone concentrations. During dust events, the Mt. Cimone mean volume concentration for coarse particles was 6.18 µm3/cm3 compared to 0.63 µm3/cm3 in dust-free conditions, while the ozone concentrations were 4% to 21% lower than the monthly mean background values. Our observations show that surface ozone concentrations were lower than the background values in air masses coming from north Africa, and when these air masses were also rich in coarse particles, the lowest ozone values were registered. Moreover, preliminary results on the possible impact of the dust events on PM10 and ozone values measured in Italian urban and rural areas showed that during the greater number of the considered dust events, significant PM10 increases and ozone decreases have occurred in the Po valley.

Ozone generation in positive and negative corona discharge fed by humid oxygen and carbon dioxide

International Nuclear Information System (INIS)

Skalny, J D; Orszagh, J; MatejcIk, S; Mason, N J

2008-01-01

The effect of humidity on ozone generation of positive and negative corona discharges fed by O 2 and CO 2 has been studied in the humidity range of 100-20 000 ppm. The experiments were carried out at an ambient temperature and pressure of 100 kPa. The increase in humidity of CO 2 conspicuously suppressed the ozone generation in negative corona discharge at all values of the input energy densities into the discharge. The effect was less pronounced in oxygen. In contrast to decrease of ozone concentration observed in negative corona discharge, the presence of water both in O 2 and CO 2 acts catalytically. The ozone concentration has been found to increase remarkably (approximately 10 times) in oxygen, if the humidity was increased from 100 to 20 000 ppm. The dependence of ozone concentration on the gas humidity exhibited an extreme. The increase observed at humidity up to approximately 5000 ppm was followed by the marginal reduction in ozone concentration. Anyway, the values of this were considerably higher than those found in dry CO 2 . The effect of humidity on ozone concentration will be discussed in relation to plasma chemical processes in studied discharges and their macroscopic parameters.

DNA bulky adducts in a Mediterranean population correlate with environmental ozone concentration, an indicator of photochemical smog.

Science.gov (United States)

Palli, Domenico; Saieva, Calogero; Grechi, Daniele; Masala, Giovanna; Zanna, Ines; Barbaro, Antongiulio; Decarli, Adriano; Munnia, Armelle; Peluso, Marco

2004-03-01

Ozone (O(3)), the major oxidant component in photochemical smog, mostly derives from photolysis of nitrogen dioxide. O(3) may have biologic effects directly and/or via free radicals reacting with other primary pollutants and has been reported to influence daily mortality and to increase lung cancer risk. Although DNA damage may be caused by ozone itself, only other photochemical reaction products (as oxidised polycyclic aromatic hydrocarbons) may form bulky DNA adducts, a reliable biomarker of genotoxic damage and cancer risk, showing a seasonal trend. In a large series consisting of 320 residents in the metropolitan area of Florence, Italy, enrolled in a prospective study for the period 1993-1998 (206 randomly sampled volunteers, 114 traffic-exposed workers), we investigated the correlation between individual levels of DNA bulky adducts and a cumulative O(3) exposure score. The average O(3) concentrations were calculated for different time windows (0-5 to 0-90 days) prior to blood drawing for each participant, based on daily measurements provided by the local monitoring system. Significant correlations between DNA adduct levels and O3 cumulative exposure scores in the last 2-8 weeks before enrollment emerged in never smokers. Correlations were highest in the subgroup of never smokers residing in the urban area and not occupationally exposed to vehicle traffic pollution, with peak values for average concentrations 4-6 weeks before enrollment (r = 0.34). Our current findings indicate that DNA adduct formation may be modulated by individual characteristics and by the cumulative exposure to environmental levels of ozone in the last 4-6 weeks, possibly through ozone-associated reactive pollutants. Copyright 2003 Wiley-Liss, Inc.

Are we approaching an Arctic ozone hole

International Nuclear Information System (INIS)

Braathen, Geir

1999-01-01

Observations during the last decade in the Arctic areas mainly made by satellite, on the ground and by probes and sensors in the stratosphere are presented. Future perspectives are deducted from the results. Factors that may influence the ozone layer negatively are: Emission rate of ozone destroying compounds, the rapidly increasing use of some substitutes, increased concentrations of steam from aeroplanes and increased amount of methane, decreasing temperature in the stratosphere due to increasing amounts of climatic gases, large volcanic eruptions and altered timing for the polar whirl dissolution. It is concluded that the ozone reduction will be larger than observed at present in the next 10 to 20 years

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.

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

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

Comparison of measured and modeled surface ozone concentrations at two different sites in Europe during the solar eclipse on August 11, 1999

International Nuclear Information System (INIS)

Zanis, P.; Zerefos, C.S.; Melas, D.

2001-01-01

The effects of the solar eclipse on 11 August 1999 on surface ozone at two sites, Thessaloniki, Greece (urban site) and Hohenpeissenberg, Germany (elevated rural site) are investigated in this study and compared with model results. The eclipse offered a unique opportunity to test our understanding of tropospheric ozone chemistry and to investigate with a simple photochemical box model the response of surface ozone to changes of solar radiation during a photolytical perturbation such as the solar eclipse. The surface ozone measurements following the eclipse display a decrease of around 10-15 ppbv at the urban station of Eptapyrgio at Thessaloniki while at Hoheneissenberg, the actual ozone data do not show any clear effect of eclipse on surface ozone. For Thessaloniki, the model results suggest that solely photochemistry can account for a significant amount of the observed surface ozone decrease during the eclipse but transport effects mask part of the photochemical effect of eclipse on surface ozone. For Hohenpeissenberg, the box model predicted an ozone decrease, but to the eclipse, of about 2ppbv in relative agreement with the magnitude of the observed ozone decrease from the 2h moving average while at the same time it inhibits the foreseen diurnal ozone increase. However, this modeled ozone decrease during the eclipse is small compared to the diurnal ozone variability due to transport effects, and hence, transport really masks such relative small changes. The different magnitude of the surface ozone decrease between the two sites indicates mainly the role of the NO x levels. Measured and modeled NO and NO 2 concentrations at Hohenpeissenbergy during the eclipse are also compared and indicate that the partitioning of NO and NO 2 in NO x is influenced clearly from the eclipse. This is not observed at Thessaloniki due to local NO x sources. (Author)

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...

Landfill leachate treatment with ozone and ozone/hydrogen peroxide systems

International Nuclear Information System (INIS)

Tizaoui, Chedly; Bouselmi, Latifa; Mansouri, Loubna; Ghrabi, Ahmed

2007-01-01

In the search for an efficient and economical method to treat a leachate generated from a controlled municipal solid waste landfill site (Jebel Chakir) in the region of greater Tunis in Tunisia, ozone alone and ozone combined with hydrogen peroxide were studied. The leachate was characterised by high COD, low biodegradability and intense dark colour. A purpose-built reactor, to avoid foaming, was used for the study. It was found that ozone efficacy was almost doubled when combined with hydrogen peroxide at 2 g/L but higher H 2 O 2 concentrations gave lower performances. Enhancement in the leachate biodegradability from about 0.1 to about 0.7 was achieved by the O 3 /H 2 O 2 system. Insignificant changes in pH that may due to buffering effect of bicarbonate was found. A small decrease in sulphate concentrations were also observed. In contrast, chloride concentration declined at the beginning of the experiment then increased to reach its initial value. Estimates of the operating costs were made for comparison purposes and it was found that the O 3 /H 2 O 2 system at 2 g/L H 2 O 2 gave the lowest cost of about 3.1 TND (∼2.3 USD)/kg COD removed

Ozone concentration characteristics in and over a high-altitude forest

Energy Technology Data Exchange (ETDEWEB)

Wooldridge, G.L.; Zeller, K.F.; Musselman, R.C. [USDA Rocky Mountain Forest and Range Experiment Station, Fort Collins, CO (United States)

1994-12-31

Four years of atmospheric ozone data from a subalpine forest site at an elevation of 3180 m above mean sea level (msl) about 55 km west of Laramie, Wyoming, U.S.A., and at a 2680 msl forest-steppe ecotone site 15 km to the southeast, have been analyzed. These sites appear to be free of any urban or industrial pollutants. Data for January through June show that the amplitude of the diurnal cycle of hourly mean values is small in winter, then increases through June. The highest monthly mean concentrations occur in April or May, and decrease in June. Episodal high O{sub 3} values were measured during spring months in connection with cutoff low pressure centers aloft and probable stratospheric intrusions. Spectral analyses yield a peak at the diurnal period and broad peaks at longer periodicities, particularly during the spring season. (orig.)

Influencing factors on microbubble ozonation treatment of acid red 3R wastewater

Directory of Open Access Journals (Sweden)

Yurong YA

2017-08-01

Full Text Available The microbubble ozonation was used to treat acid red 3R wastewater in order to investigate the influencing factors on its performance. The effects of ozone dose, initial acid red 3R concentration and activated carbon on the performance of microbubble ozonation treatment of acid red 3R wastewater are investigated. The decolorization rate, TOC removal rate, pH variation and ozone utilization efficiency in the microbubble ozonation treatment are compared under different treatment conditions. The results indicate that when increasing ozone dose or decreasing initial acid red 3R concentration, both decolorization rate and TOC removal rate of acid red 3R wastewater increase, but ozone utilization efficiency decreases. The coal-based activated carbon shows strong catalytic activity for microbubble ozonation, which could enhance the decolorization rate and TOC removal rate of acid red 3R wastewater. The better performance of microbubble ozonation treatment is achieved when the ozone dose is 48.3 mg/min and the initial acid red 3R mass concentration is 100 mg/L. Under these conditions, the decolorization efficiency reaches to 100% after treatment for 30 min, the TOC removal efficiency reaches to 78.0% after treatment for 120 min, the reaction rate constant of TOC removal is 0.015 min^-1 and the ozone utilization efficiency is higher than 99%. With addition of the coal-based activated carbon of 5 g/L, the decolorization efficiency reaches to 100% after treatment for 15 min, the TOC removal efficiency reaches to 91.2% after treatment for 120 min and the reaction rate constant of TOC removal increases to 0037 min^-1.The accumulation and following degradation of intermediate products of small molecule organic acid happens during treatment process, and as a result, the solution pH decreases initially and then increases. Therefore, the optimization of influencing factors for microbubble ozonation could increase both contaminant removal

The impacts of surface ozone pollution on winter wheat productivity in China--An econometric approach.

Science.gov (United States)

Yi, Fujin; Jiang, Fei; Zhong, Funing; Zhou, Xun; Ding, Aijun

2016-01-01

The impact of surface ozone pollution on winter wheat yield is empirically estimated by considering socio-economic and weather determinants. This research is the first to use an economic framework to estimate the ozone impact, and a unique county-level panel is employed to examine the impact of the increasing surface ozone concentration on the productivity of winter wheat in China. In general, the increment of surface ozone concentration during the ozone-sensitive period of winter wheat is determined to be harmful to its yield, and a conservative reduction of ozone pollution could significantly increase China's wheat supply. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluation of ozone emissions and exposures from consumer products and home appliances.

Science.gov (United States)

Zhang, Q; Jenkins, P L

2017-03-01

Ground-level ozone can cause serious adverse health effects and environmental impacts. This study measured ozone emissions and impacts on indoor ozone levels and associated exposures from 17 consumer products and home appliances that could emit ozone either intentionally or as a by-product of their functions. Nine products were found to emit measurable ozone, one up to 6230 ppb at a distance of 5 cm (2 inches). One use of these products increased room ozone concentrations by levels up to 106 ppb (mean, from an ozone laundry system) and personal exposure concentrations of the user by 12-424 ppb (mean). Multiple cycles of use of one fruit and vegetable washer increased personal exposure concentrations by an average of 2550 ppb, over 28 times higher than the level of the 1-h California Ambient Air Quality Standard for ozone (0.09 ppm). Ozone emission rates ranged from 1.6 mg/h for a refrigerator air purifier to 15.4 mg/h for a fruit and vegetable washer. The use of some products was estimated to contribute up to 87% of total daily exposures to ozone. The results show that the use of some products may result in potential health impacts. © 2016 The Authors. Indoor Air published by John Wiley & Sons Ltd.

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.

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

Influence of Ar addition on ozone generation in nonthermal plasmas

International Nuclear Information System (INIS)

Chen, Hsin Liang; Lee, How Ming; Chen, Shiaw Huei; Wei, Ta Chin; Chang, Moo Been

2010-01-01

Inconsistency regarding the influence of Ar addition on ozone generation in a corona discharge has been found in relevant studies. Unlike in the literature to date, a dielectric barrier discharge (DBD) reactor is adopted in this study. In addition to clarifying whether using Ar as an additive would lead to different types of behavior in a DBD and a corona discharge, this study is also motivated to explore the possible causes leading to the inconsistency. The experimental results show that adding Ar into the O 2 plasma would lead to the same influence on ozone generation in the DBD and corona discharge. Moreover, all types of controversial behavior caused by Ar addition reported in the relevant literature are observed in this study as well, indicating that the results of this study are comprehensive enough to interpret the inconsistency. By examining the experimental results in detail, it is found that the controversial influences of Ar addition on ozone generation were found using different assumptions. At a fixed applied voltage, the ozone generation might increase as the Ar concentration is increased, which results from a higher discharge power. Nevertheless, for a certain specific input energy (the ratio of discharge power to gas flow rate), the ozone concentration is lower as the Ar concentration is increased. Therefore, adding Ar is not a good way to enhance ozone generation from an economic point of view.

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.

Ozone disintegration kinetics in the reactor for tyres decomposition

International Nuclear Information System (INIS)

Golota, V.I.; Manujlenko, O.V.; Taran, G.V.; Pis'menetskij, A.S.; Zamuriev, A.A.

2010-01-01

The results of theoretical and experimental research of ozone disintegration kinetics in the chemical reactor which is developed for decomposition of tyres in the ozone-air environment are presented. Analytical expression for dependence of ozone concentration in the reactor from time and from parameters of the task, such as volume speed of ozone-air mixture feed on a reactor input, concentration of ozone on the input to the reactor, volume speed of output of the used mixture, reactor size, and square of its internal surface is obtained. It is shown that at the same speed of ozone-air mixture pro rolling through the reactor, with growth of ozone concentration on the input, value of stationary concentration in the reactor grows, remaining always less than concentration on the input. It is also shown that at the same ozone concentration on the input, with growth of speed of ozone-air mixture pro rolling through the reactor, value of stationary ozone concentration in the reactor also grows, remaining always less than ozone concentration on the input. The ozone disintegration kinetics in the reactor in a wide range of speed of ozone-air mixture pro rolling through the reactor (0.15, 0.30, 0.45, 0.60 m3/hour) and various ozone concentration on the input (5, 10, 15, 20 g/m3) is experimentally studied. It is shown that experimental results with good accuracy coincide with the theoretical. Direct experiment showed the essential influence of the internal surface of the reactor on the ozone disintegration kinetics.

Reformulated and alternative fuels: modeled impacts on regional air quality with special emphasis on surface ozone concentration.

Science.gov (United States)

Schell, Benedikt; Ackermann, Ingmar J; Hass, Heinz

2002-07-15

The comprehensive European Air Pollution and Dispersion model system was used to estimate the impacts of the usage of reformulated and alternative fuels on regional air quality with special emphasis on surface ozone concentrations. A severe western European summer smog episode in July 1994 has been used as a reference, and the model predictions have been evaluated for this episode. A forecast simulation for the year 2005 (TREND) has been performed, including the future emission development based on the current legislation and technologies available. The results of the scenario TREND are used as a baseline for the other 2005 fuel scenarios, including fuel reformulation, fuel sulfur content, and compressed natural gas (CNG) as an alternative fuel. Compared to the year 1994, significant reductions in episode peak ozone concentrations and ozone grid hours are predicted for the TREND scenario. These reductions are even more pronounced within the investigated alternative and reformulated fuel scenarios. Especially, low sulfur fuels are appropriate for an immediate improvement in air quality, because they effect the emissions of the whole fleet. Furthermore, the simulation results indicate that the introduction of CNG vehicles would also enhance air quality with respect to ozone.

Radial diffusive samplers for determination of 8-h concentration of BTEX, acetone, ethanol and ozone in ambient air during a sea breeze event

Science.gov (United States)

Roukos, Joelle; Locoge, Nadine; Sacco, Paolo; Plaisance, Hervé

2011-01-01

The radial diffusive sampler Radiello ® filled with Carbograph 4 was evaluated for monitoring BTEX, ethanol and acetone concentrations for 8-hour exposure time. The sampling rates were first evaluated in an exposure chamber under standard conditions. Benzene and toluene showed the highest sampling rates with satisfactory standard deviations. Ethylbenzene and xylenes showed medium sampling rates but higher standard deviations that can be attributed to a low affinity of these compounds with the adsorbent medium for short sampling time. Acetone has a fair result because of the increase of its partial pressure in the vicinity of the adsorbent surface in the course of sampling. The Carbograph 4 adsorbent does not seem to be suitable for sampling ethanol, likely because of its high volatility. The influences of three environmental factors (temperature (T), relative humidity (RH) and concentration level (C)) on the sampling rates were also evaluated, following a fractional factorial design at two factor levels (low and high). Results were only investigated on benzene, toluene and acetone. Temperature and relative humidity are found to be the most important factors leading to variability of the benzene and toluene sampling rates. The applicability of the sampler for 8-hour sampling was demonstrated by the results of a measurement campaign carried out during a sea breeze event. Mapping of benzene, toluene and acetone concentrations showed the highest concentrations in the industrial zone following the wind direction coming from the North. Nevertheless, the sea breeze tends to reduce the spread of the industrial plumes. On the contrary, the ozone map presents the lowest concentrations at the same industrial area indicating a net consumption of ozone. The highest ozone concentrations were found in the southeastern zone suggesting a local ozone formation.

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.

Sterilization of Microorganisms by Ozone and Ultrasound

Science.gov (United States)

Krasnyj, V. V.; Klosovskij, A. V.; Panasko, T. A.; Shvets, O. M.; Semenova, O. T.; Taran, V. S.; Tereshin, V. I.

2008-03-01

The results of recent experimental methods of sterilization of microorganisms with the use of ozone and ultrasound are presented. The main aim was to optimize the process of sterilization in water solution taking into account the ozone concentration, the power of ultrasonic emitter and the temperature of water. In the present work, the ultrasonic cavitation with simultaneous ozone generation has been used. The high ozone concentration in water solution was achieved by two-barrier glow discharge generated at atmospheric pressure and a cooling thermo-electric module. Such a sterilizer consists of ozone generator in a shape of flat electrodes covered with dielectric material and a high-voltage pulsed power supply of 250 W. The sterilization camera was equipped with ultrasonic source operated at 100 W. The experiments on the inactivation of bacteria of the Bacillus Cereus type were carried out in the distilled water saturated by ozone. The ozone concentration in the aqueous solution was 10 mg/1, whereas the ozone concentration at the output of ozone generator was 30 mg/1. The complete inactivation of spores took 15 min. Selection of the temperature of water, the ozone concentrations and ultrasonic power allowed to determine the time necessary for destroying the row of microorganisms.

Oxidation of ammonium sulfite in aqueous solutions using ozone technology

Science.gov (United States)

Li, Yue; Shang, Kefeng; Lu, Na; Li, Jie; Wu, Yan

2013-03-01

How to deal with unstable ammonium sulfite, the byproduct of flue gas desulfuration by ammonia absorption methods, has been a difficult problem in recent years. Oxidation of ammonium sulfite in aqueous solutions using ozone produced by a surface discharge system was investigated in the paper. The oxidation efficiency of ammonium sulfite by ozone and traditional air aeration were compared, and the factors including ozone concentration, gas flow rate, initial concentration of ammonium sulfite solution and reaction temperature were discussed. The results show that the oxidation efficiency of ammonium sulfite by ozone technology reached nearly 100% under the optimum conditions, which had a significant increase compared with that by air aeration.

Phenols removal using ozonation-adsorption with granular activated carbon (GAC) in rotating packed bed reactor

Science.gov (United States)

Karamah, E. F.; Leonita, S.; Bismo, S.

2018-01-01

Synthetic wastewater containing phenols was treated using combination method of ozonation-adsorption with GAC (Granular Activated Carbon) in a packed bed rotating reactor. Ozone reacts quickly with phenol and activated carbon increases the oxidation process by producing hydroxyl radicals. Performance parameters evaluated are phenol removal percentage, the quantity of hydroxyl radical formed, changes in pH and ozone utilization, dissolved ozone concentration and ozone concentration in off gas. The performance of the combination method was compared with single ozonation and single adsorption. The influence of GAC dose and initial pH of phenols were evaluated in ozonation-adsorption method. The results show that ozonation-adsorption method generates more OH radicals than a single ozonation. Quantity of OH radical formation increases with increasing pH and quantity of the GAC. The combination method prove better performance in removing phenols. At the same operation condition, ozonation-adsorption method is capable of removing of 78.62% phenols as compared with single ozonation (53.15%) and single adsorption (36.67%). The increasing percentage of phenol removal in ozonation-adsorption method is proportional to the addition of GAC dose, solution pH, and packed bed rotator speed. Maximum percentage of phenol removal is obtained under alkaline conditions (pH 10) and 125 g of GAC

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.

Effects of elevated ozone concentration on CH4 and N2O emission from paddy soil under fully open-air field conditions.

Science.gov (United States)

Tang, Haoye; Liu, Gang; Zhu, Jianguo; Kobayashi, Kazuhiko

2015-04-01

We investigated the effects of elevated ozone concentration (E-O3) on CH4 and N2O emission from paddies with two rice cultivars: an inbred Indica cultivar Yangdao 6 (YD6) and a hybrid one II-you 084 (IIY084), under fully open-air field conditions in China. A mean 26.7% enhancement of ozone concentration above the ambient level (A-O3) significantly reduced CH4 emission at tillering and flowering stages leading to a reduction of seasonal integral CH4 emission by 29.6% on average across the two cultivars. The reduced CH4 emission is associated with O3-induced reduction in the whole-plant biomass (-13.2%), root biomass (-34.7%), and maximum tiller number (-10.3%), all of which curbed the carbon supply for belowground CH4 production and its release from submerged soil to atmosphere. Although no significant difference was detected between the cultivars in the CH4 emission response to E-O3, a larger decrease in CH4 emission with IIY084 (-33.2%) than that with YD6 (-7.0%) was observed at tillering stage, which may be due to the larger reduction in tiller number in IIY084 by E-O3. Additionally, E-O3 reduced seasonal mean NOx flux by 5.7% and 11.8% with IIY084 and YD6, respectively, but the effects were not significant statistically. We found that the relative response of CH4 emission to E-O3 was not significantly different from those reported in open-top chamber experiments. This study has thus confirmed that increasing ozone concentration would mitigate the global warming potential of CH4 and suggested consideration of the feedback mechanism between ozone and its precursor emission into the projection of future ozone effects on terrestrial ecosystem. © 2014 John Wiley & Sons Ltd.

Determination of nitrous oxide and dinitrogen pentoxide concentrations in the output of air-fed ozone generators of high power density

International Nuclear Information System (INIS)

Kogelschatz, U.; Baessler, P.

1987-01-01

Infrared absorption spectroscopy is utilized to identify and measure different nitrogen oxide species in the output of air-fed ozone generators. The concentrations of nitrous oxide (N 2 O) and dinitrogen pentoxide (N 2 O 5 ) were determined over a wide parameter range of modern high power medium-frequency ozone generators. With a typical ozonation dose of 1 mg ozone per liter of drinking water, less than 10 μ N 2 O and about 20 μ N 2 O 5 are introduced into one liter of drinking water

Observed atmospheric total column ozone distribution from SCIAMACHY over Peninsular Malaysia

International Nuclear Information System (INIS)

Chooi, T K; San, L H; Jafri, M Z M

2014-01-01

The increase in atmospheric ozone has received great attention because it degrades air quality and brings hazard to human health and ecosystems. The aim of this study was to assess the seasonal variations of ozone concentrations in Peninsular Malaysia from January 2003 to December 2009 using Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY). Level-2 data of total column ozone WFMD version 1.0 with spatial resolution 1° × 1.25° were acquired through SCIAMACHY. Analysis for trend of five selected sites exhibit strong seasonal variation in atmospheric ozone concentrations, where there is a significant difference between northeast monsoon and southwest monsoon. The highest ozone values occurred over industrial and congested urban zones (280.97 DU) on August at Bayan Lepas. The lowest ozone values were observed during northeast monsoon on December at Subang (233.08 DU). In addition, the local meteorological factors also bring an impact on the atmospheric ozone. During northeast monsoon, with the higher rate of precipitation, higher relative humidity, low temperature, and less sunlight hours let to the lowest ozone concentrations. Inversely, the highest ozone concentrations observed during southwest monsoon, with the low precipitation rate, lower relative humidity, higher temperature, and more sunlight hours. Back trajectories analysis is carried out, in order to trace the path of the air parcels with high ozone concentration event, suggesting cluster of trajectory (from southwest of the study area) caused by the anthropogenic sources associated with biogenic emissions from large tropical forests, which can make important contribution to regional and global pollution

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.

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.

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.

Sensitivity of modeled ozone concentrations to uncertainties in biogenic emissions

International Nuclear Information System (INIS)

Roselle, S.J.

1992-06-01

The study examines the sensitivity of regional ozone (O3) modeling to uncertainties in biogenic emissions estimates. The United States Environmental Protection Agency's (EPA) Regional Oxidant Model (ROM) was used to simulate the photochemistry of the northeastern United States for the period July 2-17, 1988. An operational model evaluation showed that ROM had a tendency to underpredict O3 when observed concentrations were above 70-80 ppb and to overpredict O3 when observed values were below this level. On average, the model underpredicted daily maximum O3 by 14 ppb. Spatial patterns of O3, however, were reproduced favorably by the model. Several simulations were performed to analyze the effects of uncertainties in biogenic emissions on predicted O3 and to study the effectiveness of two strategies of controlling anthropogenic emissions for reducing high O3 concentrations. Biogenic hydrocarbon emissions were adjusted by a factor of 3 to account for the existing range of uncertainty in these emissions. The impact of biogenic emission uncertainties on O3 predictions depended upon the availability of NOx. In some extremely NOx-limited areas, increasing the amount of biogenic emissions decreased O3 concentrations. Two control strategies were compared in the simulations: (1) reduced anthropogenic hydrocarbon emissions, and (2) reduced anthropogenic hydrocarbon and NOx emissions. The simulations showed that hydrocarbon emission controls were more beneficial to the New York City area, but that combined NOx and hydrocarbon controls were more beneficial to other areas of the Northeast. Hydrocarbon controls were more effective as biogenic hydrocarbon emissions were reduced, whereas combined NOx and hydrocarbon controls were more effective as biogenic hydrocarbon emissions were increased

Ozone pollution affects flower numbers and timing in a simulated BAP priority calcareous grassland community

International Nuclear Information System (INIS)

Hayes, Felicity; Williamson, Jennifer; Mills, Gina

2012-01-01

Mesocosms representing the BAP Priority habitat ‘Calcareous Grassland’ were exposed to eight ozone profiles for twelve-weeks in two consecutive years. Half of the mesocosms received a reduced watering regime during the exposure periods. Numbers and timing of flowering in the second exposure period were related to ozone concentration and phytotoxic ozone dose (accumulated stomatal flux). For Lotus corniculatus, ozone accelerated the timing of the maximum number of flowers. An increase in mean ozone concentration from 30 ppb to 70 ppb corresponded with an advance in the timing of maximum flowering by six days. A significant reduction in flower numbers with increasing ozone was found for Campanula rotundifolia and Scabiosa columbaria and the relationship with ozone was stronger for those that were well-watered than for those with reduced watering. These changes in flowering timing and numbers could have large ecological impacts, affecting plant pollination and the food supply of nectar feeding insects. - Highlights: ► An increase in ozone accelerated timing of maximum flowering in Lotus corniculatus. ► Ozone reduced flower numbers in Campanula rotundifolia and Scabiosa columbaria. ► Reduced water availability did not protect most species from the effects of ozone. - Increased tropospheric ozone affected timing of flowering and maximum flower numbers in calcareous grassland mesocosms.

Effects of ozone exposures on epicuticular wax of ponderosa pine needles

International Nuclear Information System (INIS)

Bytnerowicz, A.; Turunen, M.

1994-01-01

Two-year-old ponderosa pine (Pinus ponderosa L.) seedlings were exposed during the 1989 and 1990 growing seasons to ozone in open-top chambers placed in a forested location at Shirley Meadow, Greenhorn Mountain Range, Sierra Nevada. The ozone treatments were as follows: charcoal-filtered air (CF); charcoal-filtered air with addition of ambient concentrations of ozone (CF + O 3 ); and charcoal-filtered air with addition of doubled concentrations of ozone (CF + 2 x O 3 ). Ozone effects on ponderosa pine seedlings progressed and accumulated over two seasons of exposure. Throughout the first season, increased visible injury and accelerated senescence of the foliage were noted. Subsequently, during the second season of ozone exposure, various physiological and biochemical changes in the foliage took place. All these changes led to reduced growth and biomass of the seedlings. Epistomatal waxes of needles from the CA + 2 x O 3 treatment had an occluded appearance. This phenomenon may be caused by earlier phenological development of needles from the high-ozone treatments and disturbed development and synthesis of waxes. It may also be caused by chemical degradation of waxes by exposures to high ozone concentrations. (orig.)

Exposure to ozone modulates human airway protease/antiprotease balance contributing to increased influenza A infection.

Directory of Open Access Journals (Sweden)

Matthew J Kesic

Full Text Available Exposure to oxidant air pollution is associated with increased respiratory morbidities and susceptibility to infections. Ozone is a commonly encountered oxidant air pollutant, yet its effects on influenza infections in humans are not known. The greater Mexico City area was the primary site for the spring 2009 influenza A H1N1 pandemic, which also coincided with high levels of environmental ozone. Proteolytic cleavage of the viral membrane protein hemagglutinin (HA is essential for influenza virus infectivity. Recent studies suggest that HA cleavage might be cell-associated and facilitated by the type II transmembrane serine proteases (TTSPs human airway trypsin-like protease (HAT and transmembrane protease, serine 2 (TMPRSS2, whose activities are regulated by antiproteases, such as secretory leukocyte protease inhibitor (SLPI. Based on these observations, we sought to determine how acute exposure to ozone may modulate cellular protease/antiprotease expression and function, and to define their roles in a viral infection. We utilized our in vitro model of differentiated human nasal epithelial cells (NECs to determine the effects of ozone on influenza cleavage, entry, and replication. We show that ozone exposure disrupts the protease/antiprotease balance within the airway liquid. We also determined that functional forms of HAT, TMPRSS2, and SLPI are secreted from human airway epithelium, and acute exposure to ozone inversely alters their expression levels. We also show that addition of antioxidants significantly reduces virus replication through the induction of SLPI. In addition, we determined that ozone-induced cleavage of the viral HA protein is not cell-associated and that secreted endogenous proteases are sufficient to activate HA leading to a significant increase in viral replication. Our data indicate that pre-exposure to ozone disrupts the protease/antiprotease balance found in the human airway, leading to increased influenza susceptibility.

OZONE TREATMENT OF SOLUBLE ORGANICS IN PRODUCED WATER

Energy Technology Data Exchange (ETDEWEB)

Klasson, KT

2002-03-14

This project was an extension of previous research to improve the applicability of ozonation and will help address the petroleum-industry problem of treating produced water containing soluble organics. The goal of this project was to maximize oxidation of hexane-extractable organics during a single-pass operation. The project investigated: (1) oxidant production by electrochemical and sonochemical methods, (2) increasing the mass transfer rate in the reactor by forming microbubbles during ozone injection into the produced water, and (3) using ultraviolet irradiation to enhance the reaction if needed. Several types of methodologies for treatment of soluble organics in synthetic and actual produced waters have been performed. The technologies tested may be categorized as follows: (1) Destruction via sonochemical oxidation at different pH, salt concentration, ultraviolet irradiation, and ferrous iron concentrations. (2) Destruction via ozonation at different pH, salt concentration, hydrogen peroxide concentrations, ultraviolet irradiation, temperature, and reactor configurations.

Effects of ozone on crops in north-west Pakistan

International Nuclear Information System (INIS)

Ahmad, Muhammad Nauman; Büker, Patrick; Khalid, Sofia; Van Den Berg, Leon; Shah, Hamid Ullah; Wahid, Abdul; Emberson, Lisa; Power, Sally A.; Ashmore, Mike

2013-01-01

Although ozone is well-documented to reduce crop yields in the densely populated Indo-Gangetic Plain, there is little knowledge of its effects in other parts of south Asia. We surveyed crops close to the city of Peshawar, in north-west Pakistan, for visible injury, linking this to passive measurements of ozone concentrations. Foliar injury was found on potato, onion and cotton when mean monthly ozone concentrations exceeded 45 ppb. The symptoms on onion were reproduced in ozone fumigation experiments, which also showed that daytime ozone concentrations of 60 ppb significantly reduce the growth of a major Pakistani onion variety. Aphid infestation on spinach was also reduced at these elevated ozone concentrations. The ozone concentrations measured in April–May in Peshawar, and used in the fumigation experiment, are comparable to those that have been modelled to occur over many parts of south Asia, where ozone may be a significant threat to sensitive crops. -- Highlights: ► Visible ozone injury to onion, cotton and potato was identified in north-west Pakistan. ► The symptoms on onion were reproduced by exposure to elevated ozone. ► Elevated ozone levels also significantly reduced onion growth. ► Levels of aphid infestation on spinach were lower under elevated ozone. ► These effects were observed at ozone levels that have been modelled to occur widely across south Asia. -- Ozone concentrations in NW Pakistan have adverse effects on sensitive crop species

Destruction of concentrated chlorofluorocarbons in India demonstrates an effective option to simultaneously curb climate change and ozone depletion

International Nuclear Information System (INIS)

Karstensen, Kåre Helge; Parlikar, Ulhas V.; Ahuja, Deepak; Sharma, Shiv; Chakraborty, Moumita A.; Maurya, Harivansh Prasad; Mallik, Mrinal; Gupta, P.K.; Kamyotra, J.S.; Bala, S.S.; Kapadia, B.V.

2014-01-01

Highlights: • Chlorofluorocarbons and halons are potent ozone depleting substances and greenhouse gases. • No provisions in the Montreal or in Kyoto Protocol to destroy stockpiles of concentrated CFCs. • The UNEP recommends 11 technologies for destruction of concentrated CFCs. • No studies have up to now investigated the potential of using cement kilns in developing countries. • The test demonstrated that the local Indian cement kiln was able to destroy high feeding rates of several concentrated CFC-gases effectively. - Abstract: The Montreal Protocol aims to protect the stratospheric ozone layer by phasing out production of substances that contribute to ozone depletion, currently covering over 200 individual substances. As most of these compounds are synthetic greenhouse gases, there is an opportunity to curb both ozone depletion and climate change simultaneously by requiring Parties of both the Montreal and the Kyoto Protocol to destroy their existing stocks of concentrated chlorofluorocarbons (CFCs). Many emerging countries still possess stocks which need to be destroyed in an environmentally sound manner but costs may be prohibitive. The UNEP Technology and Economic Assessment Panel identified in 2002 eleven destruction technologies which meet the criteria for environmentally sound destruction of chlorofluorocarbons. Cement kilns were among these, but no study has been reported in scientific literature assessing its destruction performance under real developing country conditions up to now. In contrast to incinerators and other treatment techniques, high temperature cement kilns are already in place in virtually every country and can, if found technical feasible, be retrofitted and adapted cost-efficiently to destroy chemicals like CFCs. India has the second largest cement industry in the world and several hazardous waste categories have been tested successfully in recent years. The objective of this study was to carry out the first full scale

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.

Ozone effects on Sphagnum mosses, carbon dioxide exchange and methane emission in boreal peatland microcosms

International Nuclear Information System (INIS)

Niemi, Riikka; Holopainen, Toini; Martikainen, Pertti J.; Silvola, Jouko

2002-01-01

Microcosms of a boreal peatland originating from an oligotrophic fen in Eastern Finland were fumigated under four ozone concentrations (0, 50, 100 and 150 ppb O 3 ) in laboratory growth chambers during two separate experiments (autumn and summer) for 4 and 6 weeks, respectively. Ozone effects on Sphagnum mosses and the fluxes of carbon dioxide and methane were evaluated. In both experiments, the three Sphagnum species studied showed only a few significant responses to ozone. In the autumn experiment, membrane permeability of S. angustifolium, measured as conductivity and magnesium leakage, was significantly higher under ozone fumigation (P=0.005 and 2 exchange during the 6-week-long summer experiment, but dark ecosystem respiration was transiently increased by ozone concentration of 100 ppb after 14 days of exposure (P<0.05). Fumigation with 100 ppb of ozone, however, more than doubled (P<0.05) methane emission from the peatland monoliths. Our results suggest that increasing tropospheric ozone concentration may cause substantial changes in the carbon gas cycling of boreal peatlands, even though these changes are not closely associated with the changes in Sphagnum vegetation

Ozone killing action against bacterial and fungal species; microbiological testing of a domestic ozone generator.

Science.gov (United States)

Dyas, A; Boughton, B J; Das, B C

1983-10-01

The action of ozone generated from a small domestic device was examined with a view to using it in clinical isolation units accommodating immunosuppressed patients. Over a six-hour period in an average size room the device did not generate sufficient ozone to suppress bacterial and fungal growth. A useful bactericidal action, against a variety of human pathogens was achieved with ozone concentrations between 0.3 to 0.9 ppm. Bactericidal ozone concentrations are close to the limit permitted for human exposure however and further experiments are indicated.

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

.19 ± 0.07 (p value ozone over this period, which are mainly driven by increases in anthropogenic emissions with a small contribution (about 7 %) from global methane concentration increases.

The exhibition to ozone diminishes the adherence and increases the membrane permeability of macrophages alveolar of rate

International Nuclear Information System (INIS)

Garcia, J.

2000-01-01

Ozone gas is generated photochemically in areas with high levels of automotive or industrial emissions, and causes irritation and inflammation of the airways if inhaled. Rat alveolar macrophages were obtained by lung lavage from male Sprague Dawley rats and used as a model to assess ozone induced cell damage (0,594 ppm for up to 60 minutes). Ozone exposure caused loss of cell adherence to a polystyrene substrate and increased membrane permeability, as noted by increases in specific 51 Cr release and citoplasmic calcium levels. The results indicate that the cell membrane is a target for ozone damage. Elevations of cytoplasmic calcium could mediate other macrophage responses to ozone , including eicosanoid and nitric oxide production, with concomitant decreases in phagocytic ability and superoxide production. (Author) [es

Ozone Production With Dielectric Barrier Discharge: Effects of Power Source and Humidity

KAUST Repository

Zhang, Xuming; Lee, Bok Jik; Im, Hong G.; Cha, Min

2016-01-01

in the production of ozone for the cases of the ac DBD, while increased voltage is more effective for the pulsed DBD. Note that the maximum ozone production efficiency (110 g/kWh) was achieved with the pulsed DBD. At the ED of ∼ 85 J/L, the ozone concentrations

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.

Reduction of date microbial load with ozone

Science.gov (United States)

Farajzadeh, Davood; Qorbanpoor, Ali; Rafati, Hasan; Isfeedvajani, Mohsen Saberi

2013-01-01

Background: Date is one of the foodstuffs that are produced in tropical areas and used worldwide. Conventionally, methyl bromide and phosphine are used for date disinfection. The toxic side effects of these usual disinfectants have led food scientists to consider safer agents such as ozone for disinfection, because food safety is a top priority. The present study was performed to investigate the possibility of replacing common conventional disinfectants with ozone for date disinfection and microbial load reduction. Materials and Methods: In this experimental study, date samples were ozonized for 3 and 5 hours with 5 and 10 g/h concentrations and packed. Ozonized samples were divided into two groups and kept in an incubator which was maintained at 25°C and 40°C for 9 months. During this period, every 3 month, microbial load (bacteria, mold, and yeast) were examined in ozonized and non-ozonized samples. Results: This study showed that ozonization with 5 g/h for 3 hours, 5 g/h for 5 hours, 10 g/h for 3 hours, and 10 g/h for 5 hours leads to about 25%, 25%, 53%, and 46% reduction in date mold and yeast load and about 6%, 9%, 76%, and 74.7% reduction in date bacterial load at baseline phase, respectively. Appropriate concentration and duration of ozonization for microbial load reduction were 10 g/h and 3 hours. Conclusion: Date ozonization is an appropriate method for microbial load reduction and leads to an increase in the shelf life of dates. PMID:24124432

Biologically resistant contaminants, primary treatment with ozone

Energy Technology Data Exchange (ETDEWEB)

Echegaray, Diego F [White Martins Gases Industriais do Nordeste S.A., Salvador, BA (Brazil); Olivieri, Nadja F [White Martins Gases Industriais S.A., Cordovil, RJ (Brazil)

1994-12-31

Organic effluent oxidation tests were conducted in petrochemical companies, in Camacari Petrochemical Complex (Northeast Brazil), to reduce treatment costs and improve the primary treatment efficiency in each industrial process. Ozone achieved 99.96 percent benzene reduction and 100 percent ethyl benzene and toluene reduction. Process efficiency is strongly dependent on the wastewater chemical composition and concentration. For this reason it is necessary to run pilot trials for each specific case. Ozone was obtained feeding commercial oxygen through a corona discharge generator and dissolved in the effluent with a bubble column. Commercial oxygen was used instead of air to increase 250 percent the ozone production, using the same ozone generator. (author). 4 figs., 2 tabs.

Biologically resistant contaminants, primary treatment with ozone

Energy Technology Data Exchange (ETDEWEB)

Echegaray, Diego F. [White Martins Gases Industriais do Nordeste S.A., Salvador, BA (Brazil); Olivieri, Nadja F. [White Martins Gases Industriais S.A., Cordovil, RJ (Brazil)

1993-12-31

Organic effluent oxidation tests were conducted in petrochemical companies, in Camacari Petrochemical Complex (Northeast Brazil), to reduce treatment costs and improve the primary treatment efficiency in each industrial process. Ozone achieved 99.96 percent benzene reduction and 100 percent ethyl benzene and toluene reduction. Process efficiency is strongly dependent on the wastewater chemical composition and concentration. For this reason it is necessary to run pilot trials for each specific case. Ozone was obtained feeding commercial oxygen through a corona discharge generator and dissolved in the effluent with a bubble column. Commercial oxygen was used instead of air to increase 250 percent the ozone production, using the same ozone generator. (author). 4 figs., 2 tabs.

The COST733 circulation type classification software: an example for surface ozone concentrations in Central Europe

Science.gov (United States)

Demuzere, Matthias; Kassomenos, P.; Philipp, A.

2011-08-01

In the framework of the COST733 Action "Harmonisation and Applications of Weather Types Classifications for European Regions" a new circulation type classification software (hereafter, referred to as cost733class software) is developed. The cost733class software contains a variety of (European) classification methods and is flexible towards choice of domain of interest, input variables, time step, number of circulation types, sequencing and (weighted) target variables. This work introduces the capabilities of the cost733class software in which the resulting circulation types (CTs) from various circulation type classifications (CTCs) are applied on observed summer surface ozone concentrations in Central Europe. Firstly, the main characteristics of the CTCs in terms of circulation pattern frequencies are addressed using the baseline COST733 catalogue (cat 2.0), at present the latest product of the new cost733class software. In a second step, the probabilistic Brier skill score is used to quantify the explanatory power of all classifications in terms of the maximum 8 hourly mean ozone concentrations exceeding the 120-μg/m3 threshold; this was based on ozone concentrations from 130 Central European measurement stations. Averaged evaluation results over all stations indicate generally higher performance of CTCs with a higher number of types. Within the subset of methodologies with a similar number of types, the results suggest that the use of CTCs based on optimisation algorithms are performing slightly better than those which are based on other algorithms (predefined thresholds, principal component analysis and leader algorithms). The results are further elaborated by exploring additional capabilities of the cost733class software. Sensitivity experiments are performed using different domain sizes, input variables, seasonally based classifications and multiple-day sequencing. As an illustration, CTCs which are also conditioned towards temperature with various weights

Ozone injury increases infection of geranium leaves by Botrytis cinerea

Energy Technology Data Exchange (ETDEWEB)

Manning, W.J.; Feder, W.A.; Perkins, I.

1970-04-01

Detached and attached, inoculated and noninoculated, ozone-injured and noninjured leaves from the lower, middle, and terminal regions of plants of geranium cultivars Enchantress and White Mountain were observed for infection by Botrytis cinerea. Previous exposure to ozone did not appreciably influence the susceptibility of leaves of either geranium cultivar to infection by B. cinerea, unless there was visible ozone injury. Ozone-injured, necrotic tissues on older attached and detached geranium leaves of both cultivars served as infection courts for B. cinerea. 14 references, 1 table.

Concentration- and flux-based ozone dose–response relationships for five poplar clones grown in North China

International Nuclear Information System (INIS)

Hu, Enzhu; Gao, Feng; Xin, Yue; Jia, Huixia; Li, Kaihui; Hu, Jianjun; Feng, Zhaozhong

2015-01-01

Concentration- and flux-based O_3 dose–response relationships were developed for poplars in China. Stomatal conductance (g_s) of five poplar clones was measured to parameterize a Jarvis-type multiplicative g_s model. The maximum g_s and other model parameters varied between clones. The strongest relationship between stomatal O_3 flux and total biomass was obtained when phytotoxic ozone dose (POD) was integrated using an uptake rate threshold of 7 nmol m"−"2 s"−"1. The R"2 value was similar between flux-based and concentration-based dose–response relationships. Ozone concentrations above 28–36 nmol mol"−"1 contributed to reducing the biomass production of poplar. Critical levels of AOT_4_0 (accumulated O_3 exposure over 40 nmol mol"−"1) and POD_7 in relation to 5% reduction in total biomass for poplar were 12 μmol mol"−"1 h and 3.8 mmol m"−"2, respectively. - Highlights: • A stomatal conductance model was calibrated for poplar clones in China. • The stomatal O_3 flux–response relationship was developed for poplars. • O_3 concentrations > 28–36 nmol mol"−"1 contributed to poplar biomass reduction. • Current ambient O_3 level in most places of China has threatened poplar growth. • Ozone sensitivity of poplar is similar to that of birch/beech. - For the first time, dose–response relationships were developed for risk assessment of O_3 impacts on poplars in China.

The Effect of Ozone and Zeolite Concentration to the Performance of the Treatment of Wastewater Containing Heavy Metal Using Flotation Process

Directory of Open Access Journals (Sweden)

Eva Karamah

2010-10-01

Full Text Available Industrial wastewater which contains heavy metal cannot be disposed to the environment directly, due to its toxicity. In this research, separation of metal from wastewater was conducted by sorptive flotation method, using Lampung natural zeolite as bonding agent. The most common diffuser used in the flotation process is air or oxygen. In this research, ozone is used as diffuser because it is a stronger oxidant and more dissolvable in water than oxygen. Besides, ozone is a coagulant aid and disinfectant. With ozone as diffuser, it is expected that the process become faster with higher efficiency. This research was conducted to determine ozone effectiveness as diffuser, compared with other diffuser, and also to determine optimum concentration and effectiveness of zeolite in flotation of iron, nickel and copper. The research result shows that separation of iron with air diffuser is 90.8%, air-oxygen diffuser is 95.7%, air-ozone (from air diffuser is 99.7%, and air-ozone (from oxygen diffuser is 99.7%. Natural zeolite is effective as bonding agent with optimum concentration equal to 2 gram/liter, producing separation percentage for iron equal to 99.70%, copper equal to 88.98% and Nickel equal to 98.46%.

Degradation of 4-chlorophenol by ozonation, γ radiation as well as ozonation combined with γ radiation

International Nuclear Information System (INIS)

Hu, J.; Wang, J.L.

2005-01-01

The radiolysis of aqueous 4-chlorophenol (4-CP) by gamma radiation in the presence of air and ozone was investigated. The 4-CP degradation, release of chloride ion, UV absorption spectrum, total organic carbon (TOC) and adsorbable organic halogens (AOX) was measured. Under the conditions of synergistic effect of ozone and radiation a complete degradation of 100 mg/L 4-CP was obtained at a dose of 6 kGy, without ozone the 4-chlorophenol was completely decomposed at 15 kGy. The total organic carbon (TOC) was reduced by 26% when ionizing radiation (at 15 kGy) combined with ozonation, and by 17% without ozone, respectively. Analysis of intermediate products resulting from synergistic effect of ozone and radiation of 4-CP was performed by using the GC/MS method. Some primary influencing factors such as irradiation time and initial 4-CP concentration were also discussed. The results showed that the degradation of 4-chlorophenol could described by first-order reaction kinetic model. There is potential for combination of irradiation with ozonation, which can remarkably reduce the irradiation dose increase the degradation efficiency of 4-CP.

Competition modifies effects of enhanced ozone/carbon dioxide concentrations on carbohydrate and biomass accumulation in juvenile Norway spruces and European beech

International Nuclear Information System (INIS)

Liu, X.; Rennenberg, H.; Kozovits, A. R.; Grams, T. E.; Blaschke, H.; Matyssek, R.

2004-01-01

Potential interactions of carbon dioxide and ozone on carbohydrate concentrations and contents were studied in Norway spruce and European beech saplings to test the hypotheses that (1) prolonged exposure to elevated carbon dioxide does not compensate for the limiting effects of ozone on the accumulation of sugars and starches, or biomass partitioning to the root; and (2) growth of mixed-species planting will repress plant responses to elevated ozone and carbon dioxide. Norway spruce and European beech saplings were acclimated for one year to ambient and elevated carbon dioxide, followed by exposure to factorial combinations of ambient and elevated ozone and carbon dioxide during the next two years. In spruce trees, sugar and starch content was greater in saplings exposed to elevated carbon dioxide; in beech, the response was the opposite. The overall conclusion was that the results did not support Hypothesis One, because the adverse effects were counteracted by elevated carbon dioxide. Regarding Hypothesis Two, it was found to be supportive for beech but not for spruce. In beech, the reduction of sugars and starch by elevated ozone and stimulation by elevated carbon dioxide were repressed by competitive interaction with spruce, whereas in spruce saplings elevated concentrations of carbon dioxide resulted in higher concentrations of sugar and starch, but only in leaves and coarse roots and only when grown in combination with beech. Elevated ozone in spruce saplings produced no significant effect on sugar or starch content either in intra- or interspecific competition. 57 refs., 1 tab., 5 figs

Competition modifies effects of enhanced ozone/carbon dioxide concentrations on carbohydrate and biomass accumulation in juvenile Norway spruces and European beech

Energy Technology Data Exchange (ETDEWEB)

Liu, X.; Rennenberg, H. [University of Freiburg, Inst. of Forest Botany and Tree Physiology, Freiburg (Germany); Kozovits, A. R.; Grams, T. E.; Blaschke, H.; Matyssek, R. [Technische Universitat Munchen, Dept. of Ecology and Ecophysiology of Plants, Freising (Germany)

2004-09-01

Potential interactions of carbon dioxide and ozone on carbohydrate concentrations and contents were studied in Norway spruce and European beech saplings to test the hypotheses that (1) prolonged exposure to elevated carbon dioxide does not compensate for the limiting effects of ozone on the accumulation of sugars and starches, or biomass partitioning to the root; and (2) growth of mixed-species planting will repress plant responses to elevated ozone and carbon dioxide. Norway spruce and European beech saplings were acclimated for one year to ambient and elevated carbon dioxide, followed by exposure to factorial combinations of ambient and elevated ozone and carbon dioxide during the next two years. In spruce trees, sugar and starch content was greater in saplings exposed to elevated carbon dioxide; in beech, the response was the opposite. The overall conclusion was that the results did not support Hypothesis One, because the adverse effects were counteracted by elevated carbon dioxide. Regarding Hypothesis Two, it was found to be supportive for beech but not for spruce. In beech, the reduction of sugars and starch by elevated ozone and stimulation by elevated carbon dioxide were repressed by competitive interaction with spruce, whereas in spruce saplings elevated concentrations of carbon dioxide resulted in higher concentrations of sugar and starch, but only in leaves and coarse roots and only when grown in combination with beech. Elevated ozone in spruce saplings produced no significant effect on sugar or starch content either in intra- or interspecific competition. 57 refs., 1 tab., 5 figs.

Elevated CO{sub 2} and ozone reduce nitrogen acquisition by Pinus halepensis from its mycorrhizal symbiont

Energy Technology Data Exchange (ETDEWEB)

Kytoeviita, M.M. [Oulu Univ., Dept. of Biology, Oulu (Finland); Thiec, D. Le [Univ. Henri Poincare-Nancy, Lab. de Biologie Forestiere, Vandoeuvre-les-Nancy (France); Dizengremel, P. [Unite Ecophysiologie Forestiere-Lab. de Pollution Atmospherique, INRA-Centre de Recherches Forestieres, Champenoux (France)

2001-07-01

The effects of 700 {mu}mol mol{sup -1} CO{sub 2} and 200 nmol mol{sup -1} ozone on photosynthesis in Pinus halepensis seedlings and on N translocation from its mycorrhizal symbiont, Paxillus involutus, were studied under nutrient-poor conditions. After 79 days of exposure, ozone reduced and elevated CO{sub 2} increased net assimilation rate. However, the effect was dependent on daily accumulated exposure. No statistically significant differences in total plant mass accumulation were observed, although ozone-treated plants tended to be smaller. Changes in atmospheric gas concentrations induced changes in allocation of resources: under elevated ozone, shoots showed high priority over roots and had significantly elevated N concentrations. As a result of different shoot N concentration and net carbon assimilation rates, photosynthetic N use efficiency was significantly increased under elevated CO{sub 2} and decreased under ozone. The differences in photosynthesis were mirrored in the growth of the fungus in symbiosis with the pine seedlings. However, exposure to CO{sub 2} and ozone both reduced the symbiosis-mediated N uptake. The results suggest an increased carbon cost of symbiosis-mediated N uptake under elevated CO{sub 2} while under ozone, plant N acquisition is preferentially shifted towards increased root uptake. (au)

Fate of return activated sludge after ozonation: an optimization study for sludge disintegration.

Science.gov (United States)

Demir, Ozlem; Filibeli, Ayse

2012-09-01

The effects of ozonation on sludge disintegration should be investigated before the application of ozone during biological treatment, in order to minimize excess sludge production. In this study, changes in sludge and supernatant after ozonation of return activated sludge were investigated for seven different ozone doses. The optimum ozone dose to avoid inhibition of ozonation and high ozone cost was determined in terms of disintegration degree as 0.05 g O3/gTS. Suspended solid and volatile suspended solid concentrations of sludge decreased by 77.8% and 71.6%, respectively, at the optimum ozone dose. Ozonation significantly decomposed sludge flocs. The release of cell contents was proved by the increase of supernatant total nitrogen (TN) and phosphorus (TP). While TN increased from 7 mg/L to 151 mg/L, TP increased from 8.8 to 33 mg/L at the optimum ozone dose. The dewaterability and filterability characteristics of the ozonated sludge were also examined. Capillary suction time increased with increasing ozone dosage, but specific resistance to filtration increased to a specific value and then decreased dramatically. The particle size distribution changed significantly as a result of floc disruption at an optimum dose of 0.05 gO3/gTS.

Automatic programmable air ozonizer

International Nuclear Information System (INIS)

Gubarev, S.P.; Klosovsky, A.V.; Opaleva, G.P.; Taran, V.S.; Zolototrubova, M.I.

2015-01-01

In this paper we describe a compact, economical, easy to manage auto air ozonator developed at the Institute of Plasma Physics of the NSC KIPT. It is designed for sanitation, disinfection of premises and cleaning the air from foreign odors. A distinctive feature of the developed device is the generation of a given concentration of ozone, approximately 0.7 maximum allowable concentration (MAC), and automatic maintenance of a specified level. This allows people to be inside the processed premises during operation. The microprocessor controller to control the operation of the ozonator was developed

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

A two-dimensional model study of past trends in global ozone

International Nuclear Information System (INIS)

Wuebbles, D.J.; Kinnison, D.E.

1988-08-01

Emissions and atmospheric concentrations of several trace gases important to atmospheric chemistry are known to have increased substantially over recent decades. Solar flux variations and the atmospheric nuclear test series are also likely to have affected stratospheric ozone. In this study, the LLNL two-dimensional chemical-radiative-transport model of the troposphere and stratosphere has been applied to an analysis of the effects that these natural and anthropogenic influences may have had on global ozone concentrations over the last three decades. In general, model determined species distributions and the derived ozone trends agree well with published analyses of land-based and satellite-based observations. Also, the total ozone and ozone distribution trends derived from CFC and other trace gas effects have a different response with latitude than the derived trends from solar flux variations, thus providing a ''signature'' for anthropogenic effects on ozone. 24 refs., 5 figs

[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.

Effect of coupled anthropogenic perturbations on stratospheric ozone

International Nuclear Information System (INIS)

Wuebbles, D.J.; Luther, F.M.; Penner, J.E.

1992-01-01

Since 1976 the greatest concern about potential perturbations to stratospheric ozone has been in regard to the atmospheric release of chlorofluorocarbons. Consequently, atmospheric measurements of ozone have usually been compared with model calculations in which only chlorocarbon perturbations are considered. However, in order to compare theoretical calculations with recent measurements of ozone and to project expected changes to atmospheric ozone levels over the next few decades, one must consider the effect from other perturbations as well. In this paper, the authors consider the coupling between several possible anthropogenic atmospheric perturbations. Namely, they examine the effects of past and possible future increases of chlorocarbons, CO 2 , N 2 O, and NO x . The focus of these calculations is on the potential changes in ozone due to chlorocarbon emissions, how other anthropogenic perturbations may have influenced the actual change in ozone over the last decade, and how these perturbations may influence future changes in ozone. Although calculations including future chlorocarbon emissions alone result in significant reductions in ozone, there is very little change in total ozone over the coming decades when other anthropogenic sources are included. Increasing CO 2 concentrations have the largest offsetting effect on the change in total ozone due to chlorocarbons. Owing to the necessity of considering emissions from a number of trace gases simultaneously, determining expected global-scale chemical and climatic effects is more complex than was previously recognized

Ozone visible symptoms and reduced root biomass in the subalpine species Pinus uncinata after two years of free-air ozone fumigation

International Nuclear Information System (INIS)

Díaz-de-Quijano, Maria; Schaub, Marcus; Bassin, Seraina; Volk, Matthias; Peñuelas, Josep

2012-01-01

Concentrations of ozone often exceed the thresholds of forest protection in the Pyrenees, but the effect of ozone on Pinus uncinata, the dominant species in subalpine forests in this mountainous range, has not yet been studied. We conducted an experiment of free-air ozone fumigation with saplings of P. uncinata fumigated with ambient O 3 (AOT40 May–Oct: 9.2 ppm h), 1.5 × O 3amb (AOT40 May–Oct: 19.2 ppm h), and 1.8 × O 3amb (AOT40 May–Oct: 32.5 ppm h) during two growing seasons. We measured chlorophyll content and fluorescence, visible injury, gas exchange, and above- and below-ground biomass. Increased exposures to ozone led to a higher occurrence and intensity of visible injury from O 3 and a 24–29% reduction of root biomass, which may render trees more susceptible to other stresses such as drought. P. uncinata is thus a species sensitive to O 3 , concentrations of which in the Pyrenees are already likely affecting this species. - Highlights: ► We assessed sensitivity to O 3 in Pinus uncinata using a free-air O 3 fumigation system. ► Occurrence and intensity of visible injury from O 3 correlated with exposure to O 3 . ► Increased O 3 reduced root biomass 24–29%. ► O 3 weakens P. uncinata, making it more susceptible to other stresses. ► Ambient [O 3 ] in the Pyrenees is thus likely to already be affecting P. uncinata stands. - Ozone concentrations similar to those in the Pyrenees affect Pinus uncinata by reducing root biomass and possibly increasing susceptibility to other stresses.

The Uncertain Role of Biogenic VOC for Boundary-Layer Ozone Concentration: Example Investigation of Emissions from Two Forest Types with a Box Model

Directory of Open Access Journals (Sweden)

Boris Bonn

2017-10-01

Full Text Available High levels of air pollution including ground level ozone significantly reduce humans’ life expectancy and cause forest damage and decreased tree growth. The French Vosges and the German Black Forest are regions well-known for having the highest tropospheric ozone concentrations at remote forested sites in Central Europe. This box model study investigates the sensitivity of atmospheric chemistry calculations of derived ozone on differently resolved forest tree composition and volatile organic compound emissions. Representative conditions were chosen for the Upper Rhine area including the Alsatian Vosges/France and the Black Forest/Germany during summer. This study aims to answer the following question: What level of input detail for Alsace and Black Forest tree mixtures is required to accurately simulate ozone formation? While the French forest in Alsace—e.g., in the Vosges—emits isoprene to a substantially higher extent than the forest at the German site, total monoterpene emissions at the two sites are rather similar. However, the individual monoterpene structures, and therefore their reactivity, differs. This causes a higher ozone production rate for Vosges forest mixture conditions than for Black Forest tree mixtures at identical NOx levels, with the difference increasing with temperature. The difference in ozone formation is analyzed in detail and the short-comings of reduced descriptions are discussed. The outcome serves as a to-do-list to allow accurate future ozone predictions influenced by the climate adaptation of forests and the change in forest species composition.

Effects of a pulsed operation on ozone production in dielectric barrier air discharges

OpenAIRE

Ruggero Barni; Ilaria Biganzoli; Elisa Dell’Orto; Claudia Riccardi

2014-01-01

We have performed an experimental investigation of ozone production in a pulsed dielectric barrier discharge (DBD) reactor. Measurements of ozone in the gas-phase as a function of the power level show that in continuous mode a maximum concentration is achieved before a decrease presumably connected with gas-phase heating. When the reactor is employed in pulsed mode, by applying a definite duty cycle, a strong increase in ozone concentration is generally observed, with a maximum which happens...

Radial diffusive sampler for the determination of 8-h ambient ozone concentrations

International Nuclear Information System (INIS)

Plaisance, H.; Gerboles, M.; Piechocki, A.; Detimmerman, F.; Saeger, E. de

2007-01-01

The 8-h ozone radial diffusive sampler was evaluated according to the CEN protocol for the validation of diffusive samplers. All the parameters regarding the sampler characteristics were found to be consistent with the requirements of this protocol apart from the blank value, which must be evaluated and subtracted at each sampling. The nominal uptake rate was determined in laboratory conditions. However, the uptake rate depends on the mass uptake, temperature, humidity and on the combination of temperature and humidity. Based on laboratory experiments, an empirical model has been established which improved the agreement between the radial sampler and the reference method. This improvement was observed under several different meteorological and emission conditions of sampling. By using the model equation of uptake rate, the data quality objective of 30% for the expanded uncertainty included in the O 3 European Directive, is easily attained. Therefore, the sampler represents an appropriate indicative method. - A passive sampler has been fully validated for monitoring 8-h ozone concentrations in ambient air

An investigation of the processes controlling ozone in the upper stratosphere

International Nuclear Information System (INIS)

Patten, K.O. Jr.; Connell, P.S.; Kinnison, D.E.; Wuebbles, D.J.; Waters, J.; Froidevaux, L.; Slanger, T.G.

1992-01-01

Photolysis of vibrationally excited oxygen produced by ultraviolet photolysis of ozone in the upper stratosphere is incorporated into the Lawrence Livermore National Laboratory 2-D zonally averaged chemical-radiative-transport model of the troposphere and stratosphere. The importance of this potential contributor of odd oxygen to the concentration of ozone is evaluated based upon recent information on vibrational distributions of excited oxygen and upon preliminary studies of energy transfer from the excited oxygen. When the energy transfer rate constants of previous work are assumed, increases in model ozone concentrations of up to 40 percent in the upper stratosphere are found, and the ozone concentrations of the model agree with measurements, including data from the Upper Atmosphere Research Satellite. However, the increase is about 0.4 percent when the larger energy transfer rate constants suggested by more recent experimental work are applied in the model. This indicates the importance of obtaining detailed information on vibrationally excited oxygen properties, particularly the state-specific energy transfer rate constants, to evaluation of tills precess for stratospheric modeling

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.

Ozone using outlook for efficiency increasing of transportation and processing of high viscous petroleum raw materials

International Nuclear Information System (INIS)

Nadirov, N.K.; Zajkina, R.F.; Mamonova, T.B.

1997-01-01

Main types of oxidation reactions preceding during petroleum feedstock ozonization are generalized. The slight ozone high paraffin-content petroleum processing sites in shown on the example will make possible to rise the pipe transport efficiency and to increase the light fraction contents in petroleums. The prospects are discussed to application of ozone forming as a by-product of radiation-chemical facilities action for petroleum feedstock processing. (author)

Ozonation of aqueous solution containing bisphenol A: Effect of operational parameters

International Nuclear Information System (INIS)

Garoma, Temesgen; Matsumoto, Shinsyu

2009-01-01

The degradation of bisphenol A (BPA) in aqueous solution by ozonation was studied. The study was conducted experimentally in a semi-batch reactor under different operational conditions, i.e., varying influent ozone gas concentration, initial BPA concentration, pH, and bicarbonate ion concentration. The results of the study indicated that ozonation could be used to effectively remove BPA from contaminated water. Keeping other operational parameters constant, the rate of BPA degradation linearly increased with ozone dosage. At pH value of 7.0, the second-order rate constants for the reaction of BPA with aqueous ozone were determined as 1.22 x 10 5 , 1.71 x 10 5 , and 2.59 x 10 5 M -1 s -1 for ozone gas dosages of 1.4, 2.2, and 5.1 mg L -1 , respectively. Bicarbonate ion in the range of 1.0-8.0 mM (61-488 ppm) showed no significant effect on BPA degradation for concentrations of BPA used in the study (23.0-57.0 μM). It was also observed that the rate of BPA degradation increased with pH up to 7.0, resulting in rate constants of 0.48 x 10 5 , 0.94 x 10 5 , and 1.71 x 10 5 M -1 s -1 at pH values of 2.0, 5.0, and 7.0, respectively; and the rate constant decreased to 1.16 x 10 5 M -1 s -1 at pH of 10.0.

Iron decreases biological effects of ozone exposure

Science.gov (United States)

CONTEXT: Ozone (0(3)) exposure is associated with a disruption of iron homeostasis and increased availability of this metal which potentially contributes to an oxidative stress and biologicaleffects. OBJECTIVE: We tested the postulate that increased concentrations of iron in c...

Ozone modelling in Eastern Austria

Energy Technology Data Exchange (ETDEWEB)

Stohl, A.; Wotawa, G.; Kromp-Kolb, H. [Univ. of Agriculture, Vienna (Austria). Inst. of Meteorology and Physics; Winiwater, W. [Austrian Research Centre, Seibersdorf (Austria); Baumann, R.; Spangl, W. [Federal Environmental Agency, Vienna (Austria)

1995-12-31

High ozone concentrations are frequently observed in Eastern Austria, often exceeding local as well as international health standards, both for short-term as well as for long-term exposures. The maximum concentrations are produced in urban plumes, e.g. of the city of Vienna, whereas regional-scale transport and production of ozone is more important for the long-term concentrations. The Pannonian Ozone Project (POP) is an Austrian research initiative to model photochemical processes on a regional as well as on a local scale with a Lagrangian model to better understand the mechanisms leading to the high ozone concentrations and to develop abatement strategies. Up to now, focus has been on the regional scale. Aircraft, tethered balloon, tetroon and intensified ground measurements are carried out to validate the model. Although the major measurement campaign will be held in summer 1995, first results from a measurement campaign in summer 1994 are already available

Distributions of chemical reactive compounds: Effects of different emissions on the formation of ozone

International Nuclear Information System (INIS)

Vogel, H.; Fiedler, F.; Vogel, B.

1993-01-01

By using the model system the concentration distributions are simulated in accordance to the conditions of the beginning of August 1990. For this situation the influence of the emissions outside of the modelling region and the influence of biogenic emissions of hydrocarbons on the ozone formation in the modeling region was investigated. Comparing the results of the different simulations one can find differences concerning the netto production of the oxidants. For the first simulation day the emissions outside of the modeling region show a strong influence on the ozone production. Integrated over the whole boundary layer the ozone mass increases by 24%. If additionally the biogenic emissions are taken into account one can find only an increase of 7% for the 1. day. In contrast at the 2. simulation day the ozone production increases by 81%. For this case the ozone concentration near the ground is up to 20 ppb higher than for the model rund without biogenic emissions. (orig./BBR) [de

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.

The impacts of surface ozone pollution on winter wheat productivity in China – An econometric approach

International Nuclear Information System (INIS)

Yi, Fujin; Jiang, Fei; Zhong, Funing; Zhou, Xun; Ding, Aijun

2016-01-01

The impact of surface ozone pollution on winter wheat yield is empirically estimated by considering socio-economic and weather determinants. This research is the first to use an economic framework to estimate the ozone impact, and a unique county-level panel is employed to examine the impact of the increasing surface ozone concentration on the productivity of winter wheat in China. In general, the increment of surface ozone concentration during the ozone-sensitive period of winter wheat is determined to be harmful to its yield, and a conservative reduction of ozone pollution could significantly increase China's wheat supply. - Highlights: • We examine the impacts of the surface ozone exposure on winter wheat yield in China. • An econometric method is used to measure the ozone impacts. • The results conclude that surface ozone is harmful to winter wheat yield in China. • We confirm that stress conditions such as drought and air particles can mitigate the adverse effect of ozone. - Surface ozone pollution is harmful to winter wheat yield in China by considering socio-economic determinants, weather, and other stress conditions like drought and air particles.

Ozone Exposure Increases Circulating Stress Hormones and Lipid Metabolites in Humans

Science.gov (United States)

RATIONALE: Air pollution has been associated with increased prevalence of type 2 diabetes; however, the mechanisms remain unknown. We have shown that acute ozone exposure in rats induces release of stress hormones, hyperglycemia, leptinemia, and gluoose intolerance that are assoc...

A depleted ozone layer absorbs less UV-B, cooling the ozone layer, increasing the amount of UV-B observed to reach Earth, heating air by dissociating tropospheric and ground-level ozone, and heating oceans very efficiently by penetrating tens of meters into the mixed layer. UV-B is 48 times more energetic ("hotter") than IR absorbed by greenhouse gases

Science.gov (United States)

Ward, P. L.

2017-12-01

This new insight into the physics of radiation shows why changes in stratospheric ozone are observed to cause changes in global temperature. By 1970, manufactured CFC gases and ozone depletion began increasing. By 1993, increases in CFCs stopped as mandated by the Montreal Protocol. By 1995, increases in ozone depletion stopped. By 1998, increases in temperature stopped until 2014. Ozone is also depleted by halogen gases emitted from major basaltic lava flows, the largest of which, since 1783, occurred at Bardarbunga in Iceland in 2014, causing 2015 and 2016 to be the hottest years on record. Throughout Earth history, the largest basaltic lava flows were contemporaneous with periods of greatest warming and greatest levels of mass extinctions. Planck's empirical law shows that temperature of matter results from oscillation of all the bonds holding matter together. The higher the temperature, the higher the frequencies and amplitudes of oscillation. Thus, radiation from a nearby hotter body will make the absorbing body hotter than radiation from a cooler body. According to the Planck-Einstein relation, thermal energy (E) in matter and in radiation equals frequency of oscillation (ν) times the Planck constant (h), E=hν—the energy of a frictionless atomic oscillator. Since frequency is observed to be a very broad continuum extending from radio signals through visible light to gamma rays, thermal energy (E=hν) must also be a very broad continuum. Thermal flux cannot be represented properly by a single number of watts per square meter, as commonly assumed throughout the physical sciences, because all frequencies coexist and the number of watts increases with frequency. Thus, UV-B solar radiation is 48 times more energetic than IR terrestrial radiation absorbed by greenhouse gases and can make the absorbing body 48 times hotter. UV-B causes sunburn; no amount of IR can cause sunburn. Furthermore, in a basic experiment, I show that air containing more than 23 times

Morphological and Metabolic Parameters of Red Blood Cells after Their Treatment with Ozone

Directory of Open Access Journals (Sweden)

Anna V. Deryugina

2018-01-01

Full Text Available The purpose of the study was to assess the morphology of red blood cells (RBC and the association of morphological parameters with lipid peroxidation processes and the content of organic phosphates in RBC when treating packed red blood cells with the ozonized saline solution (with an ozone concentration of 2 mg/l after different storage periods.Materials and methods. The morphology of human RBC, the concentration of malonic dialdehyde (MDA in RBC, the catalase activity, the concentration of ATP and 2,3-diphosphoglycerate (2,3-DPG were studied before and after treatment of RBC with the ozonized saline (with the ozone concentration of 2 mg/l after 7, 14, 21 and 30 days of storage.Results. The effect of ozone (2 ng/l in vitro on the packed red blood cells after 7–21 days of storage contributed to the recovery of RBC shape, increased the concentration of ATP and 2,3-DPG, and optimized the lipid peroxidation. Ozone did not demonstrate a pronounced positive effect on these parameters when the packed RBCs were stored for 30 days.Conclusion. The treatment of the packed RBCs with the ozonized saline solution (with the ozone concentration of 2 mg/l contributed to the recovery of the discocyte count due to optimization of lipid peroxidation processes in cell membranes and enhanced the synthesis of organic phosphates in cells due to the activation of glycolysis and the pentose phosphate pathway. This can be used to improve the morphological and metabolic status of the packed RBCs before their transfusion. 

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.

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

Analyzer for measurement of nitrogen oxide concentration by ozone content reduction in gas using solid state chemiluminescent sensor

Science.gov (United States)

Chelibanov, V. P.; Ishanin, G. G.; Isaev, L. N.

2014-05-01

Role of nitrogen oxide in ambient air is described and analyzed. New method of nitrogen oxide concentration measurement in gas phase is suggested based on ozone concentration measurement with titration by nitrogen oxide. Research of chemiluminescent sensor composition is carried out on experimental stand. The sensor produced on the base of solid state non-activated chemiluminescent composition is applied as ozone sensor. Composition is put on the surface of polymer matrix with developed surface. Sensor compositions includes gallic acid with addition of rodamine-6G. Model of interaction process between sensor composition and ozone has been developed, main products appeared during reaction are identified. The product determining the speed of luminescense appearance is found. This product belongs to quinone class. Then new structure of chemiluminescent composition was suggested, with absence of activation period and with high stability of operation. Experimental model of gas analyzer was constructed and operation algorithm was developed. It was demonstrated that developed NO measuring instrument would be applied for monitoring purposes of ambient air. This work was partially financially supported by Government of Russian Federation, Grant 074-U01

Ozone formation in a transverse-flow gas discharge

International Nuclear Information System (INIS)

Baranov, G.A.; Zinchenko, A.K.; Lednev, M.G.

1994-01-01

The measurements of the ozone concentration in flows of air and nitrogen-oxygen mixtures under transverse dc discharge are performed using an absorption spectroscopy technique. The mechanism of ozone formation in the discharge is discussed. A simple equation is suggested for the estimation of ozone concentration in the gas mixtures. The influence of water vapor on the kinetics of formation and decay of O 3 molecules is considered. The numerical estimates of the ozone concentration are made using the suggested model of plasma-chemical reactions

[Smog chamber simulation of ozone formation from atmospheric photooxidation of propane].

Science.gov (United States)

Huang, Li-hua; Mo, Chuang-rong; Xu, Yong-fu; Jia, Long

2012-08-01

Atmospheric photochemical reactions of propane and NO, were simulated with a self-made smog chamber. The effects of relative humidity (RH) and [C3H8]0/[NOx]0 ratio on ozone formation were studied. The results showed that both the maximum ozone concentration and the maximum value of incremental reactivity (IRmax) of propane decreased linearly with increasing RH. Under lower RH conditions, the occurrence time of peak ozone concentration was about 22 h after the beginning of reaction, and IRmax varied from 0.0231 to 0.0391, while under higher RH conditions the occurrence time of peak ozone concentration was 16 h, and IRmax ranged from 0.0172 to 0.0320. During the 20 h of reaction, within the first 12 h RH did not significantly affect the yield of acetone, whereas after 12 h the lower RH condition could lead to relatively greater amount of acetone. During the first 4-20 h of experiments, acetone concentrations ranged from 153 x 10(-9) to 364 x 10(-9) at 17% RH and from 167 x 10(-9) to 302 x 10(-9) at 62% RH, respectively. Maximum ozone concentrations decreased with increasing [C3H8]0/[NOx]0 ratio and a better negative linear relationship between them was obtained under the lower RH conditions. The smog chamber data and the results from simulation of the C3H8-NOx reactions using the sub-mechanism of MCM were compared, and a significant deviation was found between these two results.

Human Health and Economic Impacts of Ozone Reductions by Income Group.

Science.gov (United States)

Saari, Rebecca K; Thompson, Tammy M; Selin, Noelle E

2017-02-21

Low-income households may be disproportionately affected by ozone pollution and ozone policy. We quantify how three factors affect the relative benefits of ozone policies with household income: (1) unequal ozone reductions; (2) policy delay; and (3) economic valuation methods. We model ozone concentrations under baseline and policy conditions across the full continental United States to estimate the distribution of ozone-related health impacts across nine income groups. We enhance an economic model to include these impacts across household income categories, and present its first application to evaluate the benefits of ozone reductions for low-income households. We find that mortality incidence rates decrease with increasing income. Modeled ozone levels yield a median of 11 deaths per 100 000 people in 2005. Proposed policy reduces these rates by 13%. Ozone reductions are highest among low-income households, which increases their relative welfare gains by up to 4% and decreases them for the rich by up to 8%. The median value of reductions in 2015 is either $30 billion (in 2006 U.S. dollars) or $1 billion if reduced mortality risks are valued with willingness-to-pay or as income from increased life expectancy. Ozone reductions were relatively twice as beneficial for the lowest- compared to the highest-income households. The valuation approach affected benefits more than a policy delay or differential ozone reductions with income.

Time series analysis of ozone data in Isfahan

Science.gov (United States)

Omidvari, M.; Hassanzadeh, S.; Hosseinibalam, F.

2008-07-01

Time series analysis used to investigate the stratospheric ozone formation and decomposition processes. Different time series methods are applied to detect the reason for extreme high ozone concentrations for each season. Data was convert into seasonal component and frequency domain, the latter has been evaluated by using the Fast Fourier Transform (FFT), spectral analysis. The power density spectrum estimated from the ozone data showed peaks at cycle duration of 22, 20, 36, 186, 365 and 40 days. According to seasonal component analysis most fluctuation was in 1999 and 2000, but the least fluctuation was in 2003. The best correlation between ozone and sun radiation was found in 2000. Other variables which are not available cause to this fluctuation in the 1999 and 2001. The trend of ozone is increasing in 1999 and is decreasing in other years.

Investigations on the oxidation of nitric acid plutonium solutions with ozone

International Nuclear Information System (INIS)

Boehm, M.

1983-01-01

The reaction of ozone with nitric acid Pu solutions was studied as a function of reaction time, acid concentration and Pu concentration. Strong nitric acid Pu solutions are important in nuclear fuel element production and reprocessing. The Pu must be converted into hexavalent Pu before precipitation from the homogeneous solution together with uranium-IV, ammonia and CO 2 in the form of ammonium uranyl/plutonyl carbonate (AUPuC). Formation of a solid phase during ozonation was observed for the first time. The proneness to solidification increases with incrasing plutonium concentrations and with decreasing acid concentrations. If the formation of a solid phase during ozonation of nitric acid Pu solutions cannot be prevented, the PU-IV oxidation process described is unsuitable for industrial purposes as Pu solutions in industrial processes have much higher concentrations than the solutions used in the present investigation. (orig./EF) [de

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.

Compatibility of the ultraviolet light-ozone system for laundry waste water treatment in nuclear power plants

International Nuclear Information System (INIS)

Matsuo, Toshiaki; Nishi, Takashi; Matsuda, Masami; Izumida, Tatsuo

1997-01-01

As an alternative treatment system for laundry waste water in nuclear power plants, a system was chosen in which such organic compounds as surfactant would be oxidized by ultraviolet (UV) light and ozone. The system compatibility, UV light source, and dissolved ozone concentration were examined through experiments. First, ozone gas was absorbed in the waste water. After the dissolved ozone concentration equilibrated at the desired value, the waste water was irradiated by a mercury lamp. Then, the time dependence of the concentrations of the organic compounds, the dissolved ozone, and the hydrogen peroxide were measured to estimate the treatment rate of the system. The mercury lamp with a 10 5 -Pa vapor pressure achieved large UV radiation and a treatment rate increase, leading to a compatible system without secondary waste generation. The effect of the dissolved ozone concentration on the treatment rate was saturated when concentration was >3.3 x 10 -4 mol/10 -3 m 3 at the time UV radiation was started. Numerical results indicated the saturation was due to hydrogen peroxide generation, which prevents hydroxyl radical generation

In situ autumn ozone fumigation of mature Norway spruce - Effects on net photosynthesis

DEFF Research Database (Denmark)

Mikkelsen, Teis Nørgaard; Ro-Poulsen, H.

2002-01-01

concentration. The experiment was conducted during 70 days during the autumn. Our system could not detect any ozone effects on dark respiration, but eventually effects on dark respiration could be masked in signal noise. An inhibition of daily net photosynthesis in ozone treated shoots was apparent......, and it is was found that a mean increase in ozone concentration of 10 nl l(-1) reduced net photosynthesis with 7.4 %. This effect should be related to a pre-exposure during the season of AOT40 12.5 mul l(-1) h....

Impacts of future climate change and effects of biogenic emissions on surface ozone and particulate matter concentrations in the United States

Directory of Open Access Journals (Sweden)

Y. F. Lam

2011-05-01

Full Text Available Simulations of present and future average regional ozone and PM_2.5 concentrations over the United States were performed to investigate the potential impacts of global climate change and emissions on regional air quality using CMAQ. Various emissions and climate conditions with different biogenic emissions and domain resolutions were implemented to study the sensitivity of future air quality trends from the impacts of changing biogenic emissions. A comparison of GEOS-Chem and CMAQ was performed to investigate the effect of downscaling on the prediction of future air quality trends. For ozone, the impacts of global climate change are relatively smaller when compared to the impacts of anticipated future emissions reduction, except for the Northeast area, where increasing biogenic emissions due to climate change have stronger positive effects (increases to the regional ozone air quality. The combination effect from both climate change and emission reductions leads to approximately a 10 % or 5 ppbv decrease of the maximum daily average eight-hour ozone (MDA8 over the Eastern United States. For PM_2.5, the impacts of global climate change have shown insignificant effect, where as the impacts of anticipated future emissions reduction account for the majority of overall PM_2.5 reductions. The annual average 24-h PM_2.5 of the future-year condition was found to be about 40 % lower than the one from the present-year condition, of which 60 % of its overall reductions are contributed to by the decrease of SO₄ and NO₃ particulate matters. Changing the biogenic emissions model increases the MDA8 ozone by about 5–10 % or 3–5 ppbv in the Northeast area. Conversely, it reduces the annual average PM_2.5 by 5 % or 1.0 μg m⁻³ in the Southeast region.

The Ecophysiology Of A Pinus Ponderosa Ecosystem Exposed To High Tropospheric Ozone: Implications For Stomatal And Non-Stomatal Ozone Fluxes

Science.gov (United States)

Fares, S.; McKay, M.; Goldstein, A.

2008-12-01

Ecosystems remove ozone from the troposphere through both stomatal and non-stomatal deposition. The portion of ozone taken up through stomata has an oxidative effect causing damage. We used a multi-year dataset to assess the physiological controls over ozone deposition. Environmental parameters, CO2 and ozone fluxes were measured continuously from January 2001 to December 2006 above a ponderosa pine plantation near Blodgett Forest, Georgetown, California. We studied the dynamic of NEE (Net Ecosystem Exchange, -838 g C m-2 yr-1) and water evapotranspiration on an annual and daily basis. These processes are tightly coupled to stomatal aperture which also controlled ozone fluxes. High levels of ozone concentrations (~ 100 ppb) were observed during the spring-summer period, with corresponding high levels of ozone fluxes (~ 30 μmol m-2 h-1). During the summer season, a large portion of the total ozone flux was due to non-stomatal processes, and we propose that a plant physiological control, releasing BVOC (Biogenic Volatile Organic Compounds), is mainly responsible. We analyzed the correlations of common ozone exposure metrics based on accumulation of concentrations (AOT40 and SUM0) with ozone fluxes (total, stomatal and non-stomatal). Stomatal flux showed poorer correlation with ozone concentrations than non-stomatal flux during summer and fall seasons, which largely corresponded to the growing period. We therefore suggest that AOT40 and SUM0 are poor predictors of ozone damage and that a physiologically based metric would be more effective.

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.

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

Synthesis of pure ozone by nanosecond discharge at cryogenic temperatures

International Nuclear Information System (INIS)

Amirov, R.H.; Asinovsky, E.I.; Samoilov, I.S.

1996-01-01

Synthesis of pure ozone by nanosecond discharge at cryogenic temperatures was experimentally examined. The average ozone concentration in the volume of the discharge tube was less at cryogenic temperatures than at room temperatures. The production of condensed ozone have been determined by measuring the ozone concentration when the walls was heated and ozone evaporated. The energy yield of ozone generation at cryogenic temperatures has been calculated. The maximum value was 200 g/kWh

Role of Biogenic Volatile Organic Compounds (BVOC) emitted by urban trees on ozone concentration in cities: A review

International Nuclear Information System (INIS)

Calfapietra, C.; Fares, S.; Manes, F.; Morani, A.; Sgrigna, G.; Loreto, F.

2013-01-01

Biogenic Volatile Organic Compounds (BVOC) play a critical role in biosphere–atmosphere interactions and are key factors of the physical and chemical properties of the atmosphere and climate. However, few studies have been carried out at urban level to investigate the interactions between BVOC emissions and ozone (O 3 ) concentration. The contribution of urban vegetation to the load of BVOCs in the air and the interactions between biogenic emissions and urban pollution, including the likely formation of O 3 , needs to be investigated, but also the effects of O 3 on the biochemical reactions and physiological conditions leading to BVOC emissions are largely unknown. The effect of BVOC emission on the O 3 uptake by the trees is further complicating the interactions BVOC–O 3 , thus making challenging the estimation of the calculation of BVOC effect on O 3 concentration at urban level. -- Highlights: • We examine the role of BVOC emitted from urban trees for O 3 formation in our cities. • We state that the high BVOC emitter trees are dangerous especially in VOC limited conditions for ozone formation. • We conclude that the choice of the tree species can be very important for the quality of the air in our cities. -- BVOC emission from urban trees can be very important for ozone concentration

Time evolution of tropospheric ozone and its radiative forcing

International Nuclear Information System (INIS)

Berntsen, Terje K.; Isaksen, Ivar S.A.; Myhre, Gunnar; Stordal, Frode

1999-01-01

The overview presents results from studies of ozone concentrations from pre industrial time and up to the end of the 20th century. Different models and also a global 3-D chemistry transport model have been used. Experiments have been performed for 1850, 1900, 1950, 1960, 1970, 1980 and 1990. The radiative forcing increases with increasing ozone levels and has been steadily increasing. It has escalated towards the end of the century. Comparative evaluations with project results and external results are presented. Connections to other greenhouse gases are mentioned

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.

Experimental study of surface dielectric barrier discharge in air and its ozone production

International Nuclear Information System (INIS)

Pekárek, Stanislav

2012-01-01

For surface dielectric barrier discharge in air we studied the effects of frequency of the driving voltage on dissipated power, asymmetry of amplitudes of the discharge voltage, discharge UV emission, ozone production, ozone production of the discharge with TiO 2 and of the discharge in magnetic field. We found that for a particular voltage the dissipated power is higher for the frequency of the driving voltage of 26.3 kHz than for the frequency of 10.9 kHz; peak values of the positive half-periods of the discharge voltage are higher than peak values of the negative half-periods; intensity of the discharge UV emissions for wavelengths of 320-420 nm is for both frequencies a linear function of power; maximum ozone concentration for the frequency of the driving voltage of 26.3 kHz is obtained with smaller power than for the frequency of 10.9 kHz; placement of TiO 2 particles into the discharge chamber increases for both frequencies of the driving voltage maximum ozone concentration produced by the discharge and for the frequency of the driving voltage of 26.3 kHz increases ozone production yield. Finally, there is no observable effect of magnetic field on concentration of ozone produced by the discharge as well as on production yield. (paper)

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 HO_x 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 HO_x enhancement from the increased ionization.

Ozone Exposure-Response in Field Grown Soybean: Characterizing Intraspecific Variability of Physiology and Biochemistry

Science.gov (United States)

Crop losses due to rising tropospheric ozone concentrations ([ozone]) in 2000 were estimated to cost $1.8 to $3.9 billion in the U.S. and $3.0 to $5.5 billion in China, and are expected to grow with the predicted 25% increase in background [ozone] over the next 30 to 50 years. This challenge provide...

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.

Aerosol indirect effect on tropospheric ozone via lightning

Science.gov (United States)

Yuan, T.; Remer, L. A.; Bian, H.; Ziemke, J. R.; Albrecht, R. I.; Pickering, K. E.; Oreopoulos, L.; Goodman, S. J.; Yu, H.; Allen, D. J.

2012-12-01

Tropospheric ozone (O3) is a pollutant and major greenhouse gas and its radiative forcing is still uncertain. The unresolved difference between modeled and observed natural background O3 concentrations is a key source of the uncertainty. Here we demonstrate remarkable sensitivity of lightning activity to aerosol loading with lightning activity increasing more than 30 times per unit of aerosol optical depth over our study area. We provide observational evidence that indicates the observed increase in lightning activity is caused by the influx of aerosols from a volcano. Satellite data analyses suggest O3 is increased as a result of aerosol-induced increase in lightning and lightning produced NOx. Model simulations with prescribed lightning change corroborate the satellite data analysis. This aerosol-O3 connection is achieved via aerosol increasing lightning and thus lightning produced nitrogen oxides. This aerosol-lightning-ozone link provides a potential physical mechanism that may account for a part of the model-observation difference in background O3 concentration. More importantly, O3 production increase from this link is concentrated in the upper troposphere, where O3 is most efficient as a greenhouse gas. Both of these implications suggest a stronger O3 historical radiative forcing. This introduces a new pathway, through which increasing in aerosols from pre-industrial time to present day enhances tropospheric O3 production. Aerosol forcing thus has a warming component via its effect on O3 production. Sensitivity simulations suggest that 4-8% increase of tropospheric ozone, mainly in the tropics, is expected if aerosol-lighting-ozone link is parameterized, depending on the background emission scenario. We note, however, substantial uncertainties remain on the exact magnitude of aerosol effect on tropospheric O3 via lightning. The challenges for obtaining a quantitative global estimate of this effect are also discussed. Our results have significant implications

Is ozonation environmentally benign for reverse osmosis concentrate treatment? Four-level analysis on toxicity reduction based on organic matter fractionation.

Science.gov (United States)

Weng, Jingxia; Jia, Huichao; Wu, Bing; Pan, Bingcai

2018-01-01

Ozonation is a promising option to treat reverse osmosis concentrate (ROC). However, a systematic understanding and assessment of ozonation on toxicity reduction is insufficient. In this study, ROC sampled from a typical industrial park wastewater treatment plant of China was fractionated into hydrophobic acid (HOA), hydrophobic base (HOB), hydrophobic neutral (HON), and hydrophilic fraction (HI). Systematic bioassays covering bacteria, algae, fish, and human cell lines were conducted to reveal the role of ozonation in toxicity variation of the four ROC fractions. HOA in the raw ROC exhibited the highest toxicity, followed by HON and HI. Ozonation significantly reduced total organic carbon (TOC) and UV 254 values in HOA, HON, and HI and their toxicity except in HOB. Correlation analysis indicated that chemical data (TOC and UV 254 ) of HOA and HON correlated well with their toxicities; however, poor correlations were observed for HOB and HI, suggesting that a battery of toxicity assays is necessary. This study indicates that TOC reduction during ozonation could not fully reflect the toxicity issue, and toxicity assessment is required in conjunction with the chemical data to evaluate the effectiveness of ozonation. Copyright © 2017 Elsevier Ltd. All rights reserved.

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.

Photochemical processes and ozone production in Finnish conditions

Energy Technology Data Exchange (ETDEWEB)

Laurila, T; Hakola, H [Finnish Meteorological Inst., Helsinki (Finland). Air Quality Dept.

1997-12-31

Photochemical ozone production is observed in March-September. Highest ozone concentrations and production efficiencies are observed in spring in the northern parts and in summer in the southern parts of the country. VOC concentrations are relatively low compared to continental areas in general. During the growing season a substantial part of the total reactive mass of VOCs is of biogenic origin. Large forest areas absorb ozone substantially, decreasing the ambient ozone concentrations in central and northern parts of Finland where long-range transport of ozone is relatively important compared to local production. The aim of the work conducted at Finnish Meteorological Institute has been to characterise concentrations of photochemically active species in the boundary layer and their photochemical formation and deposition including the effects on vegetation. Also interactions between the boundary layer and free troposphere of ozone have been studied. In the future, fluxes of both biogenic species and air pollutants will be measured and the models will be further developed so that the photochemical and micrometeorological processes could be better understood

Photochemical processes and ozone production in Finnish conditions

Energy Technology Data Exchange (ETDEWEB)

Laurila, T.; Hakola, H. [Finnish Meteorological Inst., Helsinki (Finland). Air Quality Dept.

1996-12-31

Photochemical ozone production is observed in March-September. Highest ozone concentrations and production efficiencies are observed in spring in the northern parts and in summer in the southern parts of the country. VOC concentrations are relatively low compared to continental areas in general. During the growing season a substantial part of the total reactive mass of VOCs is of biogenic origin. Large forest areas absorb ozone substantially, decreasing the ambient ozone concentrations in central and northern parts of Finland where long-range transport of ozone is relatively important compared to local production. The aim of the work conducted at Finnish Meteorological Institute has been to characterise concentrations of photochemically active species in the boundary layer and their photochemical formation and deposition including the effects on vegetation. Also interactions between the boundary layer and free troposphere of ozone have been studied. In the future, fluxes of both biogenic species and air pollutants will be measured and the models will be further developed so that the photochemical and micrometeorological processes could be better understood

Modeling and direct sensitivity analysis of biogenic emissions impacts on regional ozone formation in the Mexico-U.S. border area.

Science.gov (United States)

Mendoza-Dominguez, A; Wilkinson, J G; Yang, Y J; Russell, A G

2000-01-01

A spatially and temporally resolved biogenic hydrocarbon and nitrogen oxides (NOx) emissions inventory has been developed for a region along the Mexico-U.S. border area. Average daily biogenic non-methane organic gases (NMOG) emissions for the 1700 x 1000 km2 domain were estimated at 23,800 metric tons/day (62% from Mexico and 38% from the United States), and biogenic NOx was estimated at 1230 metric tons/day (54% from Mexico and 46% from the United States) for the July 18-20, 1993, ozone episode. The biogenic NMOG represented 74% of the total NMOG emissions, and biogenic NOx was 14% of the total NOx. The CIT photochemical airshed model was used to assess how biogenic emissions impact air quality. Predicted ground-level ozone increased by 5-10 ppb in most rural areas, 10-20 ppb near urban centers, and 20-30 ppb immediately downwind of the urban centers compared to simulations in which only anthropogenic emissions were used. A sensitivity analysis of predicted ozone concentration to emissions was performed using the decoupled direct method for three dimensional air quality models (DDM-3D). The highest positive sensitivity of ground-level ozone concentration to biogenic volatile organic compound (VOC) emissions (i.e., increasing biogenic VOC emissions results in increasing ozone concentrations) was predicted to be in locations with high NOx levels, (i.e., the urban areas). One urban center--Houston--was predicted to have a slight negative sensitivity to biogenic NO emissions (i.e., increasing biogenic NO emissions results in decreasing local ozone concentrations). The highest sensitivities of ozone concentrations to on-road mobile source VOC emissions, all positive, were mainly in the urban areas. The highest sensitivities of ozone concentrations to on-road mobile source NOx emissions were predicted in both urban (either positive or negative sensitivities) and rural (positive sensitivities) locations.

Degradation of tetracycline in aqueous media by ozonation in an internal loop-lift reactor

Energy Technology Data Exchange (ETDEWEB)

Wang Yan [Department of Environmental Engineering, Wuhan University, P.O. Box C319, Luoyu Road 129, Wuhan 430079 (China); Zhang Hui, E-mail: eeng@whu.edu.cn [Department of Environmental Engineering, Wuhan University, P.O. Box C319, Luoyu Road 129, Wuhan 430079 (China); Zhang Jianhua; Lu Chen; Huang Qianqian; Wu Jie; Liu Fang [Department of Environmental Engineering, Wuhan University, P.O. Box C319, Luoyu Road 129, Wuhan 430079 (China)

2011-08-15

The degradation of tetracycline by ozone was investigated in this paper. In the laboratory scale experiments, the effect of major parameters, including pH, gas flow rate, gaseous ozone concentration, hydrogen peroxide concentration and hydroxyl radical scavenger (tert-butyl alcohol) on the degradation of tetracycline was studied. A pseudo-first order kinetic model was used to simulate the experimental results. The results indicated that the tetracycline degradation rate increased with pH, gaseous ozone concentration and gas flow rate. The addition of hydrogen peroxide or hydroxyl radical scavenger had little effect on tetracycline removal, indicating that the direct oxidation of tetracycline by ozone was dominant process and the radical contribution to the tetracycline oxidation could be neglected. The main intermediates were separated and identified as well as the simple degradation pathway of tetracycline was proposed. The COD removal reached to 35% after 90 min reaction. The acute toxicity experiments illustrated that the Daphnia magna mortality reached the maximum after 25 min ozonation and then decreased to zero after 90 min ozonation.

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

Ozone sensitivity of plants in natural communities

Energy Technology Data Exchange (ETDEWEB)

Treshow, M; Stewart, D

1973-07-01

Field fumigation studies conducted in grassland, oak, aspen, and conifer, communities established the injury threshold of prevalent plant species to ozone. Several important species, including Bromus tectorum, Quercus gambelii, and Populus tremuloides, were injured by a single 2-hours exposure to 15 pphM ozone. Over half the perennial forbs and woody species studied were visibly injured at concentrations of 30 pphM ozone or less. It is postulated that lower concentrations at prolonged or repeated exposures to ozone may impair growth and affect community vigor and stability. Continued exposure of natural plant communities to ozone is expected to initiate major shifts in the plant composition of communities. 10 references, 4 figures, 1 table.

Reclaimed water quality during simulated ozone-managed aquifer recharge hybrid

KAUST Repository

Yoon, Min

2014-06-17

A synergistic hybrid of two treatment processes, managed aquifer recharge (MAR) combined with ozonation, was proposed for wastewater reclamation and water reuse applications. Batch reactor and soil-column experiments were performed to evaluate reclaimed water quality using various chemical and bacterial analyses. The ozone process was optimized at low ozone dose (0.5 mg O3/mg DOC) based on the control of N-nitrosodimethylamine (<5 ng L-1) and bromate (<10 μg L-1), and applied prior to (i.e., O3-MAR) and after MAR (i.e., MAR-O3). This work demonstrates that effluent organic matter (EfOM) and trace organic contaminants (TOrCs) are effectively removed during the hybrid process of MAR combined ozonation, compared to MAR only. Based on fluorescence excitation-emission matrices analyses, both MAR and ozonation reduce soluble microbial (protein-like) products while only ozonation contributes in reducing humic and fulvic substances. Even at low ozone dose of 0.5 mg O3/mg DOC, the O3-MAR hybrid significantly reduced UV absorbance by ≥2 m-1, BDOC by ≥64 %, and total (Σ) TOrC concentrations by ≥70 % in the effluent water quality. However, no significant improvement (<10 %) in the removal of Σ16 TOrC concentrations was observed for the increased ozone dose at 1.0 mg O3/mg DOC during MAR combined ozonation processes. Overall, O3-MAR was effective by 10-30 % in treating effluent water than MAR based on DOC, UV254 nm EfOM, TOrC and bacterial analyses. In addition, MAR-O3 was better than O3-MAR for the reduction of fluorescence (close MQ), TOrCs (≥74 %) and total bacteria cell concentrations (>3 log reduction). Therefore, implementing MAR prior to ozonation appears to remove the bio-amenable compounds that react rapidly with ozone, thereby reducing oxidant demand and treatment efficiency. © 2014 Springer-Verlag Berlin Heidelberg.

Observations of ozone formation in power plant plumes and implications for ozone control strategies

Energy Technology Data Exchange (ETDEWEB)

Ryerson, T.B.; Trainer, M.; Holloway, J.S.; Parrish, D.D.; Huey, L.G.; Sueper, D.T.; Frost, G.J.; Donnelly, S.G.; Schauffler, S.; Atlas, E.L.; Kuster, W.C.; Goldan, P.D.; Huebler, G.; Meagher, J.F.; Fehsenfeld, F.C. [NOAA, Boulder, CO (USA). Aeronomy Lab.

2001-04-27

Data taken in aircraft transects of emissions plumes from rural US coal-fired power plants were used to confirm and quantify the nonlinear dependence of tropospheric ozone formation on plume NOx (NO plus NO{sub 2}) concentration, which is determined by plant NOx emission rate and atmospheric dispersion. The ambient availability of reactive volatile organic compounds, principally biogenic isoprene, was also found to modular ozone production rate and yield in these rural plumes. Differences of a factor of 2 or greater in plume ozone formation rates and yields as a function of NOx and volatile organic compound concentrations were consistently observed. These large differences suggest that consideration of power plant NOx emission rates and geographic locations in current and future US ozone control strategies could substantially enhance the efficacy of NOx reductions from these sources. 18 refs., 4 figs.

Nitrogen mediates above-ground effects of ozone but not below-ground effects in a rhizomatous sedge

International Nuclear Information System (INIS)

Jones, M.L.M.; Hodges, G.; Mills, G.

2010-01-01

Ozone and atmospheric nitrogen are co-occurring pollutants with adverse effects on natural grassland vegetation. Plants of the rhizomatous sedge Carex arenaria were exposed to four ozone regimes representing increasing background concentrations (background-peak): 10-30, 35-55, 60-80 and 85-105 ppb ozone at two nitrogen levels: 12 and 100 kg N ha -1 yr -1 . Ozone increased the number and proportion of senesced leaves, but not overall leaf number. There was a clear nitrogen x ozone interaction with high nitrogen reducing proportional senescence in each treatment and increasing the ozone dose (AOT40) at which enhanced senescence occurred. Ozone reduced total biomass due to significant effects on root biomass. There were no interactive effects on shoot:root ratio. Rhizome tissue N content was increased by both nitrogen and ozone. Results suggest that nitrogen mediates above-ground impacts of ozone but not impacts on below-ground resource translocation. This may lead to complex interactive effects between the two pollutants on natural vegetation. - Nitrogen alters threshold of ozone-induced senescence, but not below-ground resource allocation.

Responses of Surface Ozone Air Quality to Anthropogenic Nitrogen Deposition

Science.gov (United States)

Zhang, L.; Zhao, Y.; Tai, A. P. K.; Chen, Y.; Pan, Y.

2017-12-01

Human activities have substantially increased atmospheric deposition of reactive nitrogen to the Earth's surface, inducing unintentional effects on ecosystems with complex environmental and climate consequences. One consequence remaining unexplored is how surface air quality might respond to the enhanced nitrogen deposition through surface-atmosphere exchange. We combine a chemical transport model (GEOS-Chem) and a global land model (Community Land Model) to address this issue with a focus on ozone pollution in the Northern Hemisphere. We consider three processes that are important for surface ozone and can be perturbed by addition of atmospheric deposited nitrogen: emissions of biogenic volatile organic compounds (VOCs), ozone dry deposition, and soil nitrogen oxide (NOx) emissions. We find that present-day anthropogenic nitrogen deposition (65 Tg N a-1 to the land), through enhancing plant growth (represented as increases in vegetation leaf area index (LAI) in the model), could increase surface ozone from increased biogenic VOC emissions, but could also decrease ozone due to higher ozone dry deposition velocities. Meanwhile, deposited anthropogenic nitrogen to soil enhances soil NOx emissions. The overall effect on summer mean surface ozone concentrations show general increases over the globe (up to 1.5-2.3 ppbv over the western US and South Asia), except for some regions with high anthropogenic NOx emissions (0.5-1.0 ppbv decreases over the eastern US, Western Europe, and North China). We compare the surface ozone changes with those driven by the past 20-year climate and historical land use changes. We find that the impacts from anthropogenic nitrogen deposition can be comparable to the climate and land use driven surface ozone changes at regional scales, and partly offset the surface ozone reductions due to land use changes reported in previous studies. Our study emphasizes the complexity of biosphere-atmosphere interactions, which can have important

The influence of African air pollution on regional and global tropospheric ozone

Directory of Open Access Journals (Sweden)

A. M. Aghedo

2007-01-01

Full Text Available We investigate the influence of African biomass burning, biogenic, lightning and anthropogenic emissions on the tropospheric ozone over Africa and globally using a coupled global chemistry climate model. Our model studies indicate that surface ozone concentration may rise by up to 50 ppbv in the burning region during the biomass burning seasons. Biogenic emissions yield between 5–30 ppbv increase in the near surface ozone concentration over tropical Africa. The impact of lightning on surface ozone is negligible, while anthropogenic emissions yield a maximum of 7 ppbv increase in the annual-mean surface ozone concentration over Nigeria, South Africa and Egypt. Our results show that biogenic emissions are the most important African emission source affecting total tropospheric ozone. The influence of each of the African emissions on the global tropospheric ozone burden (TOB of 384 Tg yields about 9.5 Tg, 19.6 Tg, 9.0 Tg and 4.7 Tg for biomass burning, biogenic, lightning and anthropogenic emissions emitted in Africa respectively. The impact of each of these emission categories on African TOB of 33 Tg is 2.5 Tg, 4.1 Tg, 1.75 Tg and 0.89 Tg respectively, which together represents about 28% of the total TOB calculated over Africa. Our model calculations also suggest that more than 70% of the tropospheric ozone produced by each of the African emissions is found outside the continent, thus exerting a noticeable influence on a large part of the tropical troposphere. Apart from the Atlantic and Indian Ocean, Latin America experiences the largest impact of African emissions, followed by Oceania, the Middle East, Southeast and south-central Asia, northern North America (i.e. the United States and Canada, Europe and north-central Asia, for all the emission categories.

Percutaneous intradiscal ozone (O3)-injection: an experimental study in canines

International Nuclear Information System (INIS)

Yu Zhijian; He Xiaofeng; Chen Yong; Zeng Qingle; Liu Chihong; Zhao Zhongqing; Lu Yong; Li Yanhao

2002-01-01

Objective: To evaluate the influence of ozone on normal nucleus pulpous and the safety of intradiscal ozone-injection for the treatment of herniated lumbar disc. Methods: Ozone was injected into selected lumbar discs (3 ml) and the para-spinal space (7 ml) with 20 G Chiba needle under fluoroscopy in five canines. The ozone concentration was 30 μg/ml and 50 μg/ml respectively. Two discs were selected for each concentration. Total 20 discs were injected. Three of the canines were given one-time ozone-injection and were sacrificed for pathology one week, one month and two months respectively after the procedure, and the other two canines were given two-time ozone-injection and were sacrificed one month and two months respectively after the procedure. The specimens including nucleus pulpous, end-plate, spinal cord, nerve root, and greater psoas muscle were observed macroscopically and microscopically. Results: No serious behavior abnormalities were observed in all animals. The atrophy of nucleus pulpous could be observed one month after ozone-injection due to significant reduction of water and extensive proliferation of collagenous fiber. The influence on the atrophy of nucleus pulpous demonstrated no apparent difference between the selected two concentrations of ozone, but was more apparent with two-time injection than that with one-time injection. The end-plates increased slightly or moderately in thickness in 16 simples and a few of fibers in greater psoas muscle suffered slight atrophy in 5 samples. Conclusion: It is suggested that percutaneous intradiscal ozone-injection is a safe method, and can cause gradual atrophy of nucleus pulpous. This study provides the evidence of the feasibility and value of this procedure's application in clinics

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.

Mortality tradeoff between air quality and skin cancer from changes in stratospheric ozone

Science.gov (United States)

Eastham, Sebastian D.; Keith, David W.; Barrett, Steven R. H.

2018-03-01

Skin cancer mortality resulting from stratospheric ozone depletion has been widely studied. Similarly, there is a deep body of literature on surface ozone and its health impacts, with modeling and observational studies demonstrating that surface ozone concentrations can be increased when stratospheric air mixes to the Earth’s surface. We offer the first quantitative estimate of the trade-off between these two effects, comparing surface air quality benefits and UV-related harms from stratospheric ozone depletion. Applying an idealized ozone loss term in the stratosphere of a chemistry-transport model for modern-day conditions, we find that each Dobson unit of stratospheric ozone depletion results in a net decrease in the global annual mortality rate of ~40 premature deaths per billion population (d/bn/DU). The impacts are spatially heterogeneous in sign and magnitude, composed of a reduction in premature mortality rate due to ozone exposure of ~80 d/bn/DU concentrated in Southeast Asia, and an increase in skin cancer mortality rate of ~40 d/bn/DU, mostly in Western Europe. This is the first study to quantify air quality benefits of stratospheric ozone depletion, and the first to find that marginal decreases in stratospheric ozone around modern-day values could result in a net reduction in global mortality due to competing health impact pathways. This result, which is subject to significant methodological uncertainty, highlights the need to understand the health and environmental trade-offs involved in policy decisions regarding anthropogenic influences on ozone chemistry over the 21st century.

Improved ozone resistance of styrene-butadiene rubber cured by a combination of sulfur and ionizing radiation

International Nuclear Information System (INIS)

Basfar, A.A.; Silverman, J.

1995-01-01

Fourier Transform (FTIR) studies performed in this work indicate that high ozone resistance of Styrene-Butadiene Rubber (SBR) formulations cured by a combination of sulfur and ionizing radiation is associated with unusually high vinyl concentration. On the other hand, sulfur cured SBR formulations with low vinyl concentration have poor ozone resistance. Curing with peroxides which involves chemistry similar to that of radiation curing, also leads to high vinyl concentration (relative to sulfur curing) and high ozone resistance. Increasing the absorbed dose in sulfur-radiation cured samples decreased the high vinyl content to a point where the ozone resistance declined greatly. Carbon black was shown to reduce the absorption of both the transvinylene and the vinyl unsaturation groups, but not to the same extent in all formulations. Also, the carbon black seems to play a greater role in the absorption of the unsaturation as sulfur increases. (Author)

Improved ozone resistance of styrene-butadiene rubber cured by a combination of sulfur and ionizing radiation

International Nuclear Information System (INIS)

Basfar, A.A.; Silverman, Joseph

1995-01-01

Fourier Transform Infrared (FTIR) studies performed in this work indicate that high ozone resistance of Styrene-Butadiene Rubber (SBR) formulations cured by a combination of sulfur and ionizing radiation is associated with unusually high vinyl concentration. On the other hand, sulfur cured SBR formulations with low vinyl concentration have poor ozone resistance. Curing with peroxides which involves chemistry similar to that of radiation curing, also leads to high vinyl concentration (relative to sulfur curing) and high ozone resistance. Increasing the absorbed dose in sulfur-radiation cured samples decreased the high vinyl content to a point where the ozone resistance declined greatly. Carbon black was shown to reduce the absorption of both the transvinylene and the vinyl unsaturation groups, but not to the same extent in all formulations. Also, the carbon black seems to play a greater role in the absorption of the unsaturation as sulfur increases. (Author)

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.

An In Vitro Evaluation of Ozonized Organic Extra-Virgin Olive Oil on Giardia Lamblia Cysts.

Science.gov (United States)

Boland-Nazar, Najmeh Sadat; Eslamirad, Zahra; Sarmadian, Hossein; Ghasemikhah, Reza

2016-11-01

Giardia lamblia is a common intestinal parasite that has been reported all over the world. This study was conducted to evaluate the effect of ozonized organic extra-virgin olive oil on the cyst of G. lamblia . The olive oil was ozonized based on international standards and confirmed by the world health organization (WHO) at various times in a generator. The ozone concentration of olive oil was adjusted at 32, 64, 96, 128, 160 mg/g based on ozone absorption. Giardia lamblia cysts were isolated from heavily infected stool samples and the sucrose gradient flotation technique. Five groups of triple tubes containing Giardia cysts were exposed to olive oil with 32, 64, 96, 128, 160 ozone concentrations, and the sixth and seventh groups were exposed to non-ozonized olive oil and normal saline, respectively. The tubes were placed at room temperature, and every four hours, the mortality of the Giardia cysts was assessed. The results showed that the first five groups' mortality rate of Giardia cysts reached 100% in 100 hours. An increasing concentration of ozone in olive oil leads to an increase in the mortality rate of Giardia cysts. The results showed a significant difference in the mean time of the mortality in all the groups (P ≤ 0.05). Furthermore, the higher fatality effect of ozonized organic extra-virgin olive oil (Ozonized Olive Oil = OZO) was proved in comparison with metronidazole in vitro. We concluded that ozonized organic extra-virgin olive oil was a growth inhibitor of Giardia cysts, and concerning its compatibility with a biological system, it is recommended for further clinical trials.

Photochemical oxidants injury in rice plants. III. Effect of ozone on physiological activities in rice plants

Energy Technology Data Exchange (ETDEWEB)

Nakamura, H; Saka, H

1978-01-01

Experiments were made to determine the effect of photochemical oxidants on physiological activities of rice plants. Rice plants were fumigated with ozone at concentrations of 0.12-0.20 ppm for 2-3 hr to investigate acute injury and at 0.05 and 0.09 ppm for daily exposure from 3.0 leaf stage to assess the effect of ozone on growth. It was observed that malondialdehyde produced by disruption of the components of the membrane increased in the leaves exposed to ozone. Ozone reduced the RuBP-carboxylase activity in both young and old leaves 12-24 hr after fumigation. In the young leaves the activity of this enzyme recovered to some extent after 48 hr, but it did not show any recovery in the old leaves. On the other hand, ozone remarkably increased the peroxidase activity and slightly increased acid phosphatase in all leaves. Abnormally high ethylene evolution and oxygen uptake were detected in leaves soon after ozone fumigation. In general, high molecular protein and chlorophyll contents in the detached leaves decreased with incubation in dark, particularly in the old ones. These phenomena were more accelerated by ozone fumigation. Kinetin and benzimidazole showed significant effects on chlorophyll retention in ozone-exposed leaves. Reduction of plant growth and photosynthetic rate was recognized even in low concentration of ozone in daily exposure at 0.05 and 0.09 ppm. From these results it was postulated that ozone may cause the senescence of leaves in rice plants.

Dissolution behavior of Cu, Fe and Zn from gold sulfide concentrate during pre-oxidation using ozone in neutral media

Science.gov (United States)

Kurniawan, Mubarok, M. Zaki

2018-04-01

The aim of this work was to observe the dissolution behaviour of Cu, Fe and Zn from gold sulfide concentrate during preoxidation with ozone as the oxidant and distillation water as the media. The preoxidation experiments were carried out in five-necked reactor with variations of retention time, percent solid, particle size and oxygen dosage injected to ozone generator. The retention time was varied at 6 hours, 8 hours, 12 hours and 24 hours. The percent solid was varied at 10%, 20% and 30% while the particle size was varied at P80 -75 mesh dan P80 -20 mesh. The dosage of oxygen injection to ozone generator was varried at 1 liter per minute and 2 liter per minute. The ozone gas was produced by using ozone generator type OZ-03 and injected to the slurry by using Mazzei injector. The soluble Cu, Fe and Zn were measured by using Atomic Absorption Spectrophotometry (AAS). The concentrates were characterized by X-Ray Diffraction (XRD), mineragraphy, fire assay and Inductively Coupled Plasma (ICP). Fire assay, ICP and XRD were used to analyse the residues and froth. The solubilition of metals (Cu, Fe and Zn) was obtained through the formation of sulphate ion and H+ which decreased the pH, released a number of heat and then was continued by the formation of elemental sulphur (S°). The interaction of particles and gas yielded the formation of froth. The highest dissolution percentage of Cu, Fe and Zn was achieved through 24 hours oxidation at 20% (w/w), P80 -20 mesh and one liter per minute of oxygen injection dosage by 83.016%, 24.7303% and 91.6808%, respectively.

Simulation of Halocarbon Production and Emissions and Effects on Ozone Depletion

Science.gov (United States)

Holmes; Ellis

1997-09-01

/ This paper describes an integrated model that simulates future halocarbon production/emissions and potential ozone depletion. Applications and historical production levels for various halocarbons are discussed first. A framework is then presented for modeling future halocarbon impacts incorporating differences in underlying demands, applications, regulatory mandates, and environmental characteristics. The model is used to simulate the potential impacts of several prominent issues relating to halocarbon production, regulation, and environmental interactions, notably: changes in agricultural methyl bromide use, increases in effectiveness of bromine for ozone depletion, modifications to the elimination schedule for HCFCs, short-term expansion of CFC demand in low use compliance countries, and delays in Russian Federation compliance. Individually, each issue does not unequivocally represent a significant likely increase in long-term atmospheric halogen loading and stratospheric ozone depletion. In combination, however, these impacts could increase peak halogen concentrations and long-term integral halogen loading, resulting in higher levels of stratospheric ozone depletion and longer exposure to increased levels of UV radiation.KEY WORDS: Halocarbons; Ozone depletion; Montreal Protocol; Integrated assessment

[Degradation of 4-chlorophenol in aqueous solution by high-voltage pulsed discharge-ozone technology].

Science.gov (United States)

Wen, Yuezhong; Jiang, Xuanzhen; Liu, Weiping

2002-03-01

The combination of high voltage pulse discharge and ozonation as an advanced oxidation technology was used to investigate the degradation of 4-chlorophenol (4-CP) in water. The factors that affect the rate of degradation were discussed. The 1.95 x 10(-3) mol/L solutions of 4-CP were almost completely (96%) degraded after the discharge treatment of 30 min. The degradation of 4-CP was investigated as a function of the ozone concentration, radical scavenger and electrode distance. The rate of 4-CP degradation increases with an increase in ozone concentration and a decrease in the electrode distance from 20 mm to 10 mm. The presence of radical scavenger decreased the rate of 4-CP degradation.

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.

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.

Kudzu (Pueraria montana) invasion doubles emissions of nitric oxide and increases ozone pollution.

Science.gov (United States)

Hickman, Jonathan E; Wu, Shiliang; Mickley, Loretta J; Lerdau, Manuel T

2010-06-01

The nitrogen-fixing legume kudzu (Pueraria montana) is a widespread invasive plant in the southeastern United States with physiological traits that may lead to important impacts on ecosystems and the atmosphere. Its spread has the potential to raise ozone levels in the region by increasing nitric oxide (NO) emissions from soils as a consequence of increasing nitrogen (N) inputs and cycling in soils. We studied the effects of kudzu invasions on soils and trace N gas emissions at three sites in Madison County, Georgia in 2007 and used the results to model the effects of kudzu invasion on regional air quality. We found that rates of net N mineralization increased by up to 1,000%, and net nitrification increased by up to 500% in invaded soils in Georgia. Nitric oxide emissions from invaded soils were more than 100% higher (2.81 vs. 1.24 ng NO-N cm(-2) h(-1)). We used the GEOS-Chem chemical transport model to evaluate the potential impact of kudzu invasion on regional atmospheric chemistry and air quality. In an extreme scenario, extensive kudzu invasion leads directly to an increase in the number of high ozone events (above 70 ppb) of up to 7 days each summer in some areas, up from 10 to 20 days in a control scenario with no kudzu invasion. These results establish a quantitative link between a biological invasion and ozone formation and suggest that in this extreme scenario, kudzu invasion can overcome some of the air quality benefits of legislative control.

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.

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

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

Ozone Generation in Dry Air Using Pulsed Discharges With and Without a Solid Dielectric Layer

OpenAIRE

Samaranayake, W.J.M.; Miyahara, Y.; Namihira, T.; Katsuki, S.; Hackam, R.; Akiyama, H.; ミヤハラ, Y.; ナミヒラ, タカオ; カツキ, スナオ; アキヤマ, ヒデノリ; 浪平, 隆男; 勝木, 淳; 秋山, 秀典

2001-01-01

Energy efficient generation of ozone is very important because ozone is being used increasingly in a wide range of industrial applications. Ozonizers usually use dielectric barrier discharges and employ alternating current (ac) with consequent heat generation, which necessitates cooling. In the present study, very short duration pulsed voltage is employed resulting in reduced heating of the gas and discharge reactor. A comparison of ozone generation in dry air using a coaxial concentric elect...

Measurements of the potential ozone production rate in a forest

Science.gov (United States)

Crilley, L.; Sklaveniti, S.; Kramer, L.; Bloss, W.; Flynn, J. H., III; Alvarez, S. L.; Erickson, M.; Dusanter, S.; Locoge, N.; Stevens, P. S.; Millet, D. B.; Alwe, H. D.

2017-12-01

Biogenic volatile organic compounds (BVOC) are a significant source of organic compounds globally and alongside NOx play a key role in the formation of ozone in the troposphere. Understanding how changes in NOx concentrations feed through to altered ozone production in BVOC dominated environments will aid our understanding of future atmospheric composition, notably as developing nations transition from NOx dominated to NOx limited chemistry as a result of mitigation strategies. Here we empirically investigate this ambient ozone formation potential. We report deployment of a custom built instrument to measure in near real time the potential for in situ chemical ozone production, using an artificial light source. Our results are thus indicative of the ozone formation potential for a sampled ambient air mixture, including full VOC complexity, i.e. independent of characterization of individual organic compounds. Ground level measurements were performed as part of the PROPHET-AMOS 2016 field campaign, at a site located within a Northern Michigan forest that has typically low NOx abundance, but high isoprene and terpenoid loadings. As the ambient NOx concentrations were low during the campaign, experiments were performed in which NO was artificially added to the sampled ambient air mixture, to quantify changes in the potential ozone production rate as a function of NOx, and hence the ozone forming characteristics of the ambient air. Preliminarily results from these experiments are presented, and indicate that while ozone production increases with added NO, significant variation was observed for a given NO addition, reflecting differences in the ambient VOC chemical reactivity and ozone formation tendency.

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.

Evaluation of Novel Integrated Dielectric Barrier Discharge Plasma as Ozone Generator

Directory of Open Access Journals (Sweden)

Muhammad Nur

2017-04-01

Full Text Available This paper presents a characterization of an integrated ozone generator constructed by seven of reactors of Dielectric Barrier Discharge Plasma (DBDP. DBDP a has spiral-cylindrical configuration. Silence plasma produced ozone inside the DBDP reactor was generated by AC-HV with voltage up to 25 kV and maximum frequency of 23 kHz. As a source of ozone, dry air was pumped into the generator and controlled by valves system and a flowmeter. We found ozone concentration increased with the applied voltage, but in contrary, the concentration decreased with the flow rate of dry air. It was also found that a maximum concentration was 20 mg/L and ozone capacity of 48 g/h with an input power of 1.4 kW. Moreover, in this generator, IP efficiency of 8.13 g/kWh was obtained at input power 0.45 kW and air flow rate of 9 L/min. Therefore, be the higher ozone capacity can be produced with higher input power; however, it provided lower IP efficiency. The effect of dry air flow rate and applied voltage on ozone concentrations have been studied. At last, spiral wire copper was very corrosive done to the interaction with ozone, and it is necessary to do a research for finding the best metals as an active electrode inside of the quartz dielectric. Copyright © 2017 BCREC GROUP. All rights reserved Received: 18th July 2016; Revised: 25th September 2016; Accepted: 5th October 2016 How to Cite: Nur, M., Susan, A.I., Muhlisin, Z., Arianto, F., Kinandana, A.W., Nurhasanah, I., Sumariyah, S., Wibawa, P.J., Gunawan, G., Usman, A. (2017. Evaluation of Novel Integrated Dielectric Barrier Discharge Plasma as Ozone Generator. Bulletin of Chemical Reaction Engineering & Catalysis, 12 (1: 24-31 (doi:10.9767/bcrec.12.1.605.24-31 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.12.1.605.24-31

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.

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 (NO_x emissions from each of nine world regions. Reductions in NO_x 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 NO_x 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 NO_x reductions, the strongest inter-regional influence is for emissions from Europe affecting mortalities in Africa. Reductions of NO_x 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, NO_x reductions in India cause the greatest number of avoided mortalities per ton, mainly in India itself. Finally, by increasing global methane, NO_x 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 NO_x reductions would

Ozone adsorption on carbon nanoparticles

Science.gov (United States)

Chassard, Guillaume; Gosselin, Sylvie; Visez, Nicolas; Petitprez, Denis

2014-05-01

Carbonaceous particles produced by incomplete combustion or thermal decomposition of hydrocarbons are ubiquitous in the atmosphere. On these particles are adsorbed hundreds of chemical species. Those of great concern to health are polycyclic aromatic hydrocarbons (PAHs). During atmospheric transport, particulate PAHs react with gaseous oxidants. The induced chemical transformations may change toxicity and hygroscopicity of these potentially inhalable particles. The interaction between ozone and carbon particles has been extensively investigated in literature. However ozone adsorption and surface reaction mechanisms are still ambiguous. Some studies described a fast catalytic decomposition of ozone initiated by an atomic oxygen chemisorption followed by a molecular oxygen release [1-3]. Others suggested a reversible ozone adsorption according to Langmuir-type behaviour [4,5]. The aim of this present study is a better understanding of ozone interaction with carbon surfaces. An aerosol of carbon nanoparticles was generated by flowing synthetic air in a glass tube containing pure carbon (primary particles studied. Accordingly to literature, it has been observed that the number of gas-phase ozone molecules lost per unit particle surface area tends towards a plateau for high ozone concentration suggesting a reversible ozone adsorption according to a Langmuir mechanism. We calculated the initial reaction probability between O3 and carbon particles.An initial uptake coefficient of 1.10-4 was obtained. Similar experiments were realized by selecting the particles size with a differential mobility analyser. We observed a strong size-dependent increase in reactivity with the decrease of particles size. This result is relevant for the health issues. Indeed the smallest particles are most likely to penetrate deep into the lungs. Competitive reactions between ozone and other species like H2O or atomic oxygen were also considered. Oxygen atoms were generated by photolysis of O3

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.

Ozone direct oxidation kinetics of Cationic Red X-GRL in aqueous solution

International Nuclear Information System (INIS)

Zhao Weirong; Wu Zhongbiao; Wang Dahui

2006-01-01

This study characterizes the ozonation of the azo dye Cationic Red X-GRL in the presence of TBA (tert-butyl alcohol), a scavenger of hydroxyl radical, in a bubble column reactor. Effects of oxygen flow rate, temperature, initial dye concentration, and pH were investigated through a series of batch tests. Generally, enhancing oxygen flow rate enhanced the removal of dye. However, there was a minimum removal of dye at temperature 298 K. Increasing or decreasing temperature enhanced the degradation of dye. Increasing the initial dye concentration decreased the removal of dye while the ozonation rate increased. The rate constants and the kinetic regime of the reaction between ozone and dye were obtained by fitting the experimental data to a kinetics model based on a second order overall reaction, first order with respect to both ozone and dye. The Hatta numbers of the reactions were between 0.039 and 0.083, which indicated that the reaction occurred in the liquid bulk. The direct oxidation rate constant k D was correlated with temperature by a modified Arrhenius Equation with an activation energy E a of 15.538 kJ mol -1

Generation of ozone by Ns-width pulsed power

International Nuclear Information System (INIS)

Shimomura, Naoyuki; Wakimoto, Masaya; Shinke, Yosuke; Nagata, Masayoshi; Namihira, Takao; Akiyama, Hidenori

2002-01-01

The demand of ozone will be increasing for wholesome and environment-conscious sterilizations. The generation of ozone using the pulsed power discharge will apply electron accelerations around the head of streamer discharge principally. The breakdown in reactor often limits the efficient generation. Therefore, the pulse shape should be controlled for dimension of the reactor. It is clear that a pulse shortening is one of effective approaches. Pulsed power voltage with ns-width applies for ozone generation. The effects, on concentration and efficiency of generation, of pulse shape, repetition rate of pulse, flow rate of oxygen gas, and dimension and configuration of reactor, are discussed. The dimension and configuration of the reactor are optimized for the pulse width

Effect of solar radiation on surface ozone in Cairo

Energy Technology Data Exchange (ETDEWEB)

Rizk, H F.S. [National Research Centre, Air Pollution Research Dept., Cairo (Egypt)

1992-04-01

Measurements of surface ozone content over an urban area in Cairo were conducted during a year, May 1989 to April 1990, while solar radiation at the same area was measured. Low and high concentrations of ozone are compared with those recommended by the WHO expert committee regarding the daily cycle of ozone concentration. 15 refs.

Increased ultrafine particles and carbon monoxide concentrations are associated with asthma exacerbation among urban children

Science.gov (United States)

Evans, Kristin A.; Halterman, Jill S.; Hopke, Philip K.; Fagnano, Maria; Rich, David Q.

2014-01-01

Objectives Increased air pollutant concentrations have been linked to several asthma-related outcomes in children, including respiratory symptoms, medication use, and hospital visits. However, few studies have examined effects of ultrafine particles in a pediatric population. Our primary objective was to examine the effects of ambient concentrations of ultrafine particles on asthma exacerbation among urban children and determine whether consistent treatment with inhaled corticosteroids could attenuate these effects. We also explored the relationship between asthma exacerbation and ambient concentrations of accumulation mode particles, fine particles (≤ 2.5 micrograms [μm]; PM2.5), carbon monoxide, sulfur dioxide, and ozone. We hypothesized that increased 1 to 7 day concentrations of ultrafine particles and other pollutants would be associated with increases in the relative odds of an asthma exacerbation, but that this increase in risk would be attenuated among children receiving school-based corticosteroid therapy. Methods We conducted a pilot study using data from 3–10 year-old children participating in the School-Based Asthma Therapy trial. Using a time-stratified case-crossover design and conditional logistic regression, we estimated the relative odds of a pediatric asthma visit treated with prednisone (n=96 visits among 74 children) associated with increased pollutant concentrations in the previous 7 days. We re-ran these analyses separately for children receiving medications through the school-based intervention and children in a usual care control group. Results Interquartile range increases in ultrafine particles and carbon monoxide concentrations in the previous 7 days were associated with increases in the relative odds of a pediatric asthma visit, with the largest increases observed for 4-day mean ultrafine particles (interquartile range=2088 p/cm3; OR=1.27; 95% CI=0.90–1.79) and 7-day mean carbon monoxide (interquartile range=0.17 ppm; OR=1.63; 95

Ozone applied to the homogeneous charge compression ignition engine to control alcohol fuels combustion

International Nuclear Information System (INIS)

Masurier, J.-B.; Foucher, F.; Dayma, G.; Dagaut, P.

2015-01-01

Highlights: • Ozone was useful to control combustion phasing of alcohol fuels in HCCI engine. • Ozone helps to improve the combustion and advance its phasing. • Butanol is more impacted by ozone than methanol and ethanol. • HCCI combustion parameters may be controlled by managing ozone concentration. • Kinetics demonstrates that alcohol fuels are initially oxidized by O-atoms. - Abstract: The present investigation examines the impact of seeding the intake of an HCCI engine with ozone, one of the most oxidizing chemical species, on the combustion of three alcohol fuels: methanol, ethanol and n-butanol. The research was performed through engine experiments and constant volume computations. The results showed that increasing the ozone concentration led to an improvement in combustion coupled with a combustion advance. It was also observed, by comparing the results for each fuel selected, that n-butanol is the most impacted by ozone seeding and methanol the least. Further analyses of the experimental results showed that the alcohol fuel combustion can be controlled with ozone, which presents an interesting potential. Finally, computation results confirmed the experimental results observed. They also showed that in presence of ozone, alcohol fuels are not initially oxidized by molecular oxygen but by O-atoms coming from the ozone decomposition.

Effects of Greenhouse Gas Increase and Stratospheric Ozone Depletion on Stratospheric Mean Age of Air in 1960-2010

Science.gov (United States)

Li, F.; Newman, P. A.; Pawson, S.; Perlwitz, J.

2017-12-01

The strength of the stratospheric Brewer-Dobson circulation (BDC) in a changing climate has been extensively studied, but the relative importance of greenhouse gas (GHG) increases and stratospheric ozone depletion in driving the BDC changes remains uncertain. This study separates the impacts of GHG and stratospheric ozone forcings on stratospheric mean age of air in the 1960-2010 period using the Goddard Earth Observing System Model (GEOS) Chemistry-Climate Model (CCM). The experiment compares a set of controlled simulations using a coupled atmosphere-ocean version of the GEOS CCM, in which either GHGs, or stratospheric ozone, or both factors evolve over time. The model results show that GHGs and stratospheric ozone have about equal contributions to the simulated mean age decrease. It is also found that GHG increases account for about two thirds of the enhanced strength of the lower stratospheric residual circulation. The results show that ozone depletion causes an increase in the mean age of air in the Antarctic summer lower stratosphere through two processes: 1) a seasonal delay in the Antarctic polar vortex breakup, that inhibits young mid-latitude air from mixing with the older air inside the vortex; and 2) enhanced Antarctic downwelling, that brings older air from middle and upper stratosphere into the lower stratosphere.

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

The holes in the ozone scare

Energy Technology Data Exchange (ETDEWEB)

Maduro, R.; Schauerhamer, R.

1992-05-01

For the authors, the ozone hole is more politic than scientific, and is caused by anthropogenic CFC, the ozone concentration reduction measured in the antarctic stratosphere is a natural phenomena: ozone destruction by chlorides and bromides coming from volcanos and oceans. The ozone hole was discovered in 1956 and not in 1985. For the greenhouse effect, the CO[sub 2] part is very small in comparison with the atmospheric water vapour part. (A.B.). refs., figs., tabs.

An Estimation of the Climatic Effects of Stratospheric Ozone Losses during the 1980s. Appendix K

Science.gov (United States)

MacKay, Robert M.; Ko, Malcolm K. W.; Shia, Run-Lie; Yang, Yajaing; Zhou, Shuntai; Molnar, Gyula

1997-01-01

In order to study the potential climatic effects of the ozone hole more directly and to assess the validity of previous lower resolution model results, the latest high spatial resolution version of the Atmospheric and Environmental Research, Inc., seasonal radiative dynamical climate model is used to simulate the climatic effects of ozone changes relative to the other greenhouse gases. The steady-state climatic effect of a sustained decrease in lower stratospheric ozone, similar in magnitude to the observed 1979-90 decrease, is estimated by comparing three steady-state climate simulations: 1) 1979 greenhouse gas concentrations and 1979 ozone, II) 1990 greenhouse gas concentrations with 1979 ozone, and III) 1990 greenhouse gas concentrations with 1990 ozone. The simulated increase in surface air temperature resulting from nonozone greenhouse gases is 0.272 K. When changes in lower stratospheric ozone are included, the greenhouse warming is 0.165 K, which is approximately 39% lower than when ozone is fixed at the 1979 concentrations. Ozone perturbations at high latitudes result in a cooling of the surface-troposphere system that is greater (by a factor of 2.8) than that estimated from the change in radiative forcing resulting from ozone depiction and the model's 2 x CO, climate sensitivity. The results suggest that changes in meridional heat transport from low to high latitudes combined with the decrease in the infrared opacity of the lower stratosphere are very important in determining the steady-state response to high latitude ozone losses. The 39% compensation in greenhouse warming resulting from lower stratospheric ozone losses is also larger than the 28% compensation simulated previously by the lower resolution model. The higher resolution model is able to resolve the high latitude features of the assumed ozone perturbation, which are important in determining the overall climate sensitivity to these perturbations.

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

Effects of medical ozone upon healthy equine joints: Clinical and laboratorial aspects.

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Cynthia do Prado Vendruscolo

Full Text Available The aim of this study was to verify whether transient inflammatory reactions induced by intra-articular medicinal ozone administration affect joint components, by in vivo evaluation of inflammatory (prostaglandin E2, Substance P, Interleukin-6, Interleukine-1, Tumor Necrosis Factor, anti-inflammatory (Interleukin-10 and oxidative (superoxide dismutase activity and oxidative burst biomarkers and extracellular matrix degradation products (chondroitin sulphate and hyaluronic acid in synovial fluid.The effects of medicinal ozone were analyzed at two ozone concentrations (groups A and B, 20 and 40 μg/ml, respectively, using oxygen-injected joints as controls (group C; each group received ten treatments (15 ml gas per treatment. Physical evaluation, evaluation of lameness, ultrasonography, and synovial fluid analysis were performed.All joints presented mild and transient effusion throughout the study. Group B exhibited the highest lameness score on day 14 (P<0.05, detected by the lameness measurement system, probably because of the higher ozone concentration. All groups exhibited increased ultrasonography scores on day 14 (P < 0.05. Groups A and B exhibited increased proteins concentrations on day 21 (P<0.05. There was no change in hyaluronic acid concentration or the percentage of high-molecular weight hyaluronic acid throughout the experiment. Chondroitin sulfate concentrations decreased in group B, and did not change in group A and C, indicating that neither treatment provoked extracellular matrix catabolism. Cytokine and eicosanoid concentrations were not significantly changed.The ozonetherapy did not cause significant inflammation process or cartilage degradation, therefore, ozonetherapy is safe at both evaluated doses.

Intermittent Ozonation to Reduce Excess Biological Sludge in SBR

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Afshin Takdastan

2009-09-01

Full Text Available A combination of ozonation and an aerobic biological process such as the activated sludge has been recently developed as an alternative solution for sludge reduction with the objective of minimizing the excess biological sludge production. In this study, two SBR reactors each with a capacity of 20 liters and controlled by an on-line system are used. Once the steady state conditions were set in the reactors, sampling and testing of such parameters as COD, MLSS, MLVSS, DO, SOUR, SVI, residual ozone, and Y coefficient were performed over the 8 months of research. Results showed that during the solid retention time of 10 days, the kinetic coefficients of Y and Kd were 0.58 mg biomass/mg COD and 0.058 1/day, respectively. In the next stage of the study, different concentrations of ozone in the reactor were intermittently used to reduce the excess biological sludge production. The results showed that 22 mg of ozone per 1 gram of MLSS in the reactor was able to reduce the yield coefficient Y from 0.58 to 0.23 mg Biomass/mg COD. In other words, the excess biological sludge reduced by 60% but the soluble COD increased slightly in the effluent and the removal percentage decreased from 92 in the blank reactor to 76 in the test reactor. While the amount of SVI and SOUR for this level of ozone concentration reached 6 mgO2/h.gVSS and 27 ml/g, respectively. No excess sludge was observed in the reactor for an ozone concentration of 27 mg per 1 gram of MLSS.

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

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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.

An exploratory analysis of the relationship between ambient ozone and particulate matter concentrations during early pregnancy and selected birth defects in Texas

International Nuclear Information System (INIS)

Vinikoor-Imler, Lisa C.; Stewart, Thomas G.; Luben, Thomas J.; Davis, J. Allen; Langlois, Peter H.

2015-01-01

We performed an exploratory analysis of ozone (O 3 ) and fine particulate matter (PM 2.5 ) concentrations during early pregnancy and multiple types of birth defects. Data on births were obtained from the Texas Birth Defects Registry (TBDR) and the National Birth Defects Prevention Study (NBDPS) in Texas. Air pollution concentrations were previously determined by combining modeled air pollution concentrations with air monitoring data. The analysis generated hypotheses for future, confirmatory studies; although many of the observed associations were null. The hypotheses are provided by an observed association between O 3 and craniosynostosis and inverse associations between PM 2.5 and septal and obstructive heart defects in the TBDR. Associations with PM 2.5 for septal heart defects and ventricular outflow tract obstructions were null using the NBDPS. Both the TBDR and the NBPDS had inverse associations between O 3 and septal heart defects. Further research to confirm the observed associations is warranted. - Highlights: • Air pollution concentrations combined modeled air data and air monitoring data. • No associations were observed between the majority of birth defects and PM 2.5 and O 3 . • Estimated associations between PM 2.5 and certain heart defects varied by dataset. • Results were suggestive of an inverse association between O 3 and septal heart defects. • Higher O 3 concentrations may be associated with increased odds of craniosynostosis. - Although most observed associations between ozone and fine particulate matter concentrations and birth defects were null, some were present and warrant further consideration

Ozone from fireworks: Chemical processes or measurement interference?

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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.

Will the ozone shield of the earth be destroyed by the increasing use of nitrogen fertilizers

International Nuclear Information System (INIS)

Huebner, H.

1981-01-01

The increase of the world's population is accompanied by a parallel increase of the application of nitrogen fertilizers since an extensive expansion of land use cannot keep up with the currently increasing population. Continuous transformations of matter in soils are accompanied by isotopic variations. Using delta 15 N-NO 3 variations as an example, it is shown that in the aerobic zone values are becoming more negative at the beginning, whereas they are shifted anew to the positive during transition to the anaerobic zone. Accountable for the latter change of delta 15 N-NO 3 values is the isotope effect in denitrification which allows to determine the degree of denitrification. The increasing fertilizer use is accompanied by some environmental problems. NO 3 in groundwaters and N 2 O originating from denitrification processes are such environmental problems. Apprehensions for destroying the ozone shield of the earth by the increasing N 2 O in the stratosphere and the current knowledge of the global N cycle are discussed. Natural variations in the stratospheric ozone content are much higher than those resulting from possible NOsub(x)-catalyzed decomposition reactions of ozone. (author)

Association between outdoor ozone and compensated acute respiratory diseases among workers in Quebec (Canada).

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Adam-Poupart, Ariane; Labrèche, France; Busque, Marc-Antoine; Brand, Allan; Duguay, Patrice; Fournier, Michel; Zayed, Joseph; Smargiassi, Audrey

2015-01-01

Respiratory effects of ozone in the workplace have not been extensively studied. Our aim was to explore the relationship between daily average ozone levels and compensated acute respiratory problems among workers in Quebec between 2003 and 2010 using a time-stratified case-crossover design. Health data came from the Workers' Compensation Board. Daily concentrations of ozone were estimated using a spatiotemporal model. Conditional logistic regressions, with and without adjustment for temperature, were used to estimate odds ratios (ORs, per 1 ppb increase of ozone), and lag effects were assessed. Relationships with respiratory compensations in all industrial sectors were essentially null. Positive non-statistically significant associations were observed for outdoor sectors, and decreased after controlling for temperature (ORs of 0.98; 1.01 and 1.05 at Lags 0, 1 and 2 respectively). Considering the predicted increase of air pollutant concentrations in the context of climate change, closer investigation should be carried out on outdoor workers.

Sensitivity analysis of surface ozone to emission controls in Beijing and its neighboring area during the 2008 Olympic Games

Institute of Scientific and Technical Information of China (English)

Yi Gao; Meigen Zhang

2012-01-01

The regional air quality modeling system RAMS (Regional Atmospheric Modeling System)-CMAQ (Community Multi-scale Air Quality modeling system) is applied to analyze temporal and spatial variations in surface ozone concentration over Beijing and its surrounding region from July to October 2008.Comparison of simulated and observed meteorological elements and concentration of nitrogen oxides (NOx) and ozone at one urban site and three rural sites during Olympic Games show that model can generally reproduce the main observed feature of wind,temperature and ozone,but NOx concentration is overestimated.Although ozone concentration decreased during Olympics,high ozone episodes occurred on 24 July and 24 August with concentration of 360 and 245 μg/m3 at Aoyuncun site,respectively.The analysis of sensitive test,with and without emission controls,shows that emission controls could reduce ozone concentration in the afternoon when ozone concentration was highest but increase it at night and in the morning.The evolution of the weather system during the ozone episodes (24 July and 24 August) indicates that hot and dry air and a stable weak pressure field intensified the production of ozone and allowed it to accumulate.Process analysis at the urban site and rural site shows that under favorable weather condition on 24 August,horizontal transport was the main contributor of the rural place and the pollution from the higher layer would be transported to the surface layer.On 24 July,as the wind velocity was smaller,the impact of transport on the rural place was not obvious.

Sensitivity analysis of surface ozone to emission controls in Beijing and its neighboring area during the 2008 Olympic Games.

Science.gov (United States)

Gao, Yi; Zhang, Meigen

2012-01-01

The regional air quality modeling system RAMS (regional atmospheric modeling system)-CMAQ (community multi-scale air quality modeling system) is applied to analyze temporal and spatial variations in surface ozone concentration over Beijing and its surrounding region from July to October 2008. Comparison of simulated and observed meteorological elements and concentration of nitrogen oxides (NOx) and ozone at one urban site and three rural sites during Olympic Games show that model can generally reproduce the main observed feature of wind, temperature and ozone, but NOx concentration is overestimated. Although ozone concentration decreased during Olympics, high ozone episodes occurred on 24 July and 24 August with concentration of 360 and 245 microg/m3 at Aoyuncun site, respectively. The analysis of sensitive test, with and without emission controls, shows that emission controls could reduce ozone concentration in the afternoon when ozone concentration was highest but increase it at night and in the morning. The evolution of the weather system during the ozone episodes (24 July and 24 August) indicates that hot and dry air and a stable weak pressure field intensified the production of ozone and allowed it to accumulate. Process analysis at the urban site and rural site shows that under favorable weather condition on 24 August, horizontal transport was the main contributor of the rural place and the pollution from the higher layer would be transported to the surface layer. On 24 July, as the wind velocity was smaller, the impact of transport on the rural place was not obvious.

Stratospheric ozone: History and concepts and interactions with climate

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Bekki S.

2009-02-01

Full Text Available Although in relatively low concentration of a few molecules per million of e e air molecules, atmospheric ozone (trioxygen O3 is essential to sustaining life on the surface of the Earth. Indeed, by absorbing solar radiation between 240 and 320 nm, it shields living organisms including humans from the very harmful ultraviolet radiation UV-B. About 90% of the ozone resides in the stratosphere, a region that extends from the tropopause, whose altitude ranges from 7 km at the poles to 17 km in the tropics, to the stratopause located at about 50 km altitude. Stratospheric ozone is communally referred as the « ozone layer ». Unlike the atmosphere surrounding it, the stratosphere is vertically stratified and stable because the temperature increases with height within it. This particularity originates from heating produced by the absorption of UV radiation by stratospheric ozone. The present chapter describes the main mechanisms that govern the natural balance of ozone in the stratosphere, and its disruption under the influence of human activities.

Prolonged ozone exposure in an allergic airway disease model: Adaptation of airway responsiveness and airway remodeling

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Park Chang-Soo

2006-02-01

Full Text Available Abstract Background Short-term exposure to high concentrations of ozone has been shown to increase airway hyper-responsiveness (AHR. Because the changes in AHR and airway inflammation and structure after chronic ozone exposure need to be determined, the goal of this study was to investigate these effects in a murine model of allergic airway disease. Methods We exposed BALB/c mice to 2 ppm ozone for 4, 8, and 12 weeks. We measured the enhanced pause (Penh to methacholine and performed cell differentials in bronchoalveolar lavage fluid. We quantified the levels of IL-4 and IFN-γ in the supernatants of the bronchoalveolar lavage fluids using enzyme immunoassays, and examined the airway architecture under light and electron microscopy. Results The groups exposed to ozone for 4, 8, and 12 weeks demonstrated decreased Penh at methacholine concentrations of 12.5, 25, and 50 mg/ml, with a dose-response curve to the right of that for the filtered-air group. Neutrophils and eosinophils increased in the group exposed to ozone for 4 weeks compared to those in the filtered-air group. The ratio of IL-4 to INF-γ increased significantly after exposure to ozone for 8 and 12 weeks compared to the ratio for the filtered-air group. The numbers of goblet cells, myofibroblasts, and smooth muscle cells showed time-dependent increases in lung tissue sections from the groups exposed to ozone for 4, 8, and 12 weeks. Conclusion These findings demonstrate that the increase in AHR associated with the allergic airway does not persist during chronic ozone exposure, indicating that airway remodeling and adaptation following repeated exposure to air pollutants can provide protection against AHR.

AN EVALUATION OF OZONE EXPOSURE METRICS FOR A SEASONALLY DROUGHT STRESSED PONDEROSA PINE ECOSYSTEM. (R826601)

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Ozone stress has become an increasingly significant factor in cases of forest decline reported throughout the world. Current metrics to estimate ozone exposure for forest trees are derived from atmospheric concentrations and assume that the forest is physiologically active at ...

Effects of elevated ozone, carbon dioxide, and the combination of both on the grain quality of Chinese hybrid rice

International Nuclear Information System (INIS)

Wang, Yunxia; Song, Qiling; Frei, Michael; Shao, Zaisheng; Yang, Lianxin

2014-01-01

The effects of CO 2 and/or O 3 elevation on rice grain quality were investigated in chamber experiments with gas fumigation performed from transplanting until maturity in 2011 and 2012. Compared with the control (current CO 2 and O 3 concentration), elevated CO 2 caused a tendency of an increase in grain chalkiness and a decrease in mineral nutrient concentrations. In contrast, elevated O 3 significantly increased grain chalkiness and the concentrations of essential nutrients, while changes in starch pasting properties indicated a trend of deterioration in the cooking and eating quality. In the combination of elevated CO 2 and O 3 treatment, only chalkiness degree was significantly affected. It is concluded that the O 3 concentration projected for the coming few decades will have more substantial effects on grain quality of Chinese hybrid rice than the projected high CO 2 concentration alone, and the combination of two gases caused fewer significant changes in grain quality than individual gas treatments. - Highlights: • We investigated the effects of carbon dioxide and/or ozone elevation on rice grain quality. • Elevated ozone concentration had substantial effects on grain quality under current carbon dioxide concentration. • Elevated carbon dioxide concentration mitigated the impact of elevated ozone concentration on rice grain quality. - Exposure of Chinese hybrid rice to elevated ozone and CO 2 during growth causes fewer changes in grain quality than ozone exposure alone

Enhanced nitrogen deposition exacerbates the negative effect of increasing background ozone in Dactylis glomerata, but not Ranunculus acris

Energy Technology Data Exchange (ETDEWEB)

Wyness, Kirsten, E-mail: kirnes@ceh.ac.uk [Centre for Ecology and Hydrology (CEH), Environment Centre Wales, Deiniol Road, Bangor LL57 2UW (United Kingdom); Newcastle Institute for Research on the Environment and Sustainability - NIRES, Devonshire Building, Newcastle University, Newcastle Upon Tyne NE1 7RU (United Kingdom); Mills, Gina; Jones, Laurence [Centre for Ecology and Hydrology (CEH), Environment Centre Wales, Deiniol Road, Bangor LL57 2UW (United Kingdom); Barnes, Jeremy D. [Newcastle Institute for Research on the Environment and Sustainability - NIRES, Devonshire Building, Newcastle University, Newcastle Upon Tyne NE1 7RU (United Kingdom); Jones, Davey L. [School of the Environment and Natural Resources, Bangor University, Bangor, Gwynedd LL57 2UW (United Kingdom)

2011-10-15

The combined impacts of simulated increased nitrogen (N) deposition (75 kg N ha{sup -1} yr{sup -1}) and increasing background ozone (O{sub 3}) were studied using two mesotrophic grassland species (Dactylis glomerata and Ranunculus acris) in solardomes, by means of eight O{sub 3} treatments ranging from 15.5 ppb to 92.7 ppb (24 h average mean). A-C{sub i} curves were constructed for each species to gauge effects on photosynthetic efficiency and capacity, and effects on biomass partitioning were determined after 14 weeks. Increasing the background concentration of O{sub 3} reduced the healthy above ground and root biomass of both species, and increased senesced biomass. N fertilisation increased biomass production in D. glomerata, and a significantly greater than additive effect of O{sub 3} and N on root biomass was evident. In contrast, R. acris biomass was not affected by high N. The study shows the combined effects of these pollutants have differential implications for carbon allocation patterns in common grassland species. - Highlights: > Dactylis glomerata and Ranunculus acris enhanced senescence with increasing O{sub 3}. > Ozone effects on root biomass were larger than on shoot biomass in both species. > N deposition exacerbated the negative O{sub 3} effect on D. glomerata root biomass. > Inter-specific differences in the response to O{sub 3} and N combined exposure. - Synergistic effects of elevated O{sub 3} and N were observed in below ground C-partitioning in the grass Dactylis glomerata, but not in the forb Ranunculus acris.

Impact of meteorological data resolution on the forecasted ozone concentrations during the ESCOMPTE IOP2a and IOP2b

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Menut, Laurent; Coll, Isabelle; Cautenet, Sylvie

2005-03-01

During the summer 2001, several photo-oxidant pollution episodes were documented around Marseilles-Fos-Berre in the South of France within the framework of the ESCOMPTE campaign. The site is composed of large cities (Marseilles, Aix, and Toulon), significant factories (Fos-Berre), a dense road network, and extensive rural area. Both biogenic and anthropogenic emissions are thus significative. Located close to the Mediterranean Sea and framed by the Pyrenees and the Alps Mountains, pollutant concentrations are under the influence of strong emissions as well as a complex meteorology. During the whole summer 2001, the chemistry-transport model CHIMERE was used to forecast pollutant concentrations. The ECMWF forecast meteorological fields were used as forcing, with a raw spatial and temporal resolution of 0.5° and 3 h, respectively. It was observed that even if the synoptic dynamic processes were correctly described, the resolution was not always able to detail small-scale dynamics (sea breezes and orographical winds). To estimate the impact of meteorological forcing on the modeled concentration accuracy, an intercomparison exercise has thus been carried out on the same episode but with two sets of meteorological data: ECMWF data (with horizontal and temporal resolution of 0.5° and 3 h) and data from the mesoscale model RAMS (3 km and 1 h). The two sets of meteorological data are compared and discussed in terms of raw differences as a function of time and location, and in terms of induced discrepancies between the modeled and observed ozone concentration fields. It was shown that even if the RAMS model provides a better description of land-sea breezes and nocturnal boundary layer processes, the simulated ozone time series are satisfactory with the two meteorological forcings. In the context of ozone forecast, the scores are better with ECMWF. This is attributed to the diffusive aspect of these data that will more easily catch localized peaks, while a small error in

Influence of oxygen concentration on ethylene removal using dielectric barrier discharge

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Takahashi, Katsuyuki; Motodate, Takuma; Takaki, Koichi; Koide, Shoji

2018-01-01

Ethylene gas is decomposed using a dielectric barrier discharge plasma reactor for long-period preservation of fruits and vegetables. The oxygen concentration in ambient gas is varied from 2 to 20% to simulate the fruit and vegetable transport container. The experimental results show that the efficiency of ethylene gas decomposition increases with decreasing oxygen concentration. The reactions of ethylene molecules with ozone are analyzed by Fourier transform infrared spectrometry. The analysis results show that the oxidization process by ozone is later than that by oxygen atoms. The amount of oxygen atoms that contribute to ethylene removal increases with decreasing oxygen concentration because the reaction between oxygen radicals and oxygen molecules is suppressed at low oxygen concentrations. Ozone is completely removed and the energy efficiency of C2H4 removal is increased using manganese dioxide as a catalyst.

Ambient Ozone Concentrations and the Risk of Perforated and Nonperforated Appendicitis: A Multicity Case-Crossover Study

Science.gov (United States)

Tanyingoh, Divine; Dixon, Elijah; Johnson, Markey; Wheeler, Amanda J.; Myers, Robert P.; Bertazzon, Stefania; Saini, Vineet; Madsen, Karen; Ghosh, Subrata; Villeneuve, Paul J.

2013-01-01

Background: Environmental determinants of appendicitis are poorly understood. Past work suggests that air pollution may increase the risk of appendicitis. Objectives: We investigated whether ambient ground-level ozone (O3) concentrations were associated with appendicitis and whether these associations varied between perforated and nonperforated appendicitis. Methods: We based this time-stratified case-crossover study on 35,811 patients hospitalized with appendicitis from 2004 to 2008 in 12 Canadian cities. Data from a national network of fixed-site monitors were used to calculate daily maximum O3 concentrations for each city. Conditional logistic regression was used to estimate city-specific odds ratios (ORs) relative to an interquartile range (IQR) increase in O3 adjusted for temperature and relative humidity. A random-effects meta-analysis was used to derive a pooled risk estimate. Stratified analyses were used to estimate associations separately for perforated and nonperforated appendicitis. Results: Overall, a 16-ppb increase in the 7-day cumulative average daily maximum O3 concentration was associated with all appendicitis cases across the 12 cities (pooled OR = 1.07; 95% CI: 1.02, 1.13). The association was stronger among patients presenting with perforated appendicitis for the 7-day average (pooled OR = 1.22; 95% CI: 1.09, 1.36) when compared with the corresponding estimate for nonperforated appendicitis [7-day average (pooled OR = 1.02, 95% CI: 0.95, 1.09)]. Heterogeneity was not statistically significant across cities for either perforated or nonperforated appendicitis (p > 0.20). Conclusions: Higher levels of ambient O3 exposure may increase the risk of perforated appendicitis. PMID:23842601

Computational analysis of ozonation in bubble columns

International Nuclear Information System (INIS)

Quinones-Bolanos, E.; Zhou, H.; Otten, L.

2002-01-01

This paper presents a new computational ozonation model based on the principle of computational fluid dynamics along with the kinetics of ozone decay and microbial inactivation to predict the performance of ozone disinfection in fine bubble columns. The model can be represented using a mixture two-phase flow model to simulate the hydrodynamics of the water flow and using two transport equations to track the concentration profiles of ozone and microorganisms along the height of the column, respectively. The applicability of this model was then demonstrated by comparing the simulated ozone concentrations with experimental measurements obtained from a pilot scale fine bubble column. One distinct advantage of this approach is that it does not require the prerequisite assumptions such as plug flow condition, perfect mixing, tanks-in-series, uniform radial or longitudinal dispersion in predicting the performance of disinfection contactors without carrying out expensive and tedious tracer studies. (author)

Treatability study of the effluent containing reactive blue 21 dye by ozonation and the mass transfer study of ozone

Science.gov (United States)

Velpula, Priyadarshini; Ghuge, Santosh; Saroha, Anil K.

2018-04-01

Ozonation is a chemical treatment process in which ozone reacts with the pollutants present in the effluent by infusion of ozone into the effluent. This study includes the effect of various parameters such as inlet ozone dose, pH of solution and initial concentration of dye on decolorization of dye in terms CRE. The maximum CRE of 98.62% with the reaction rate constant of 0.26 min-1 is achieved in 18 minutes of reaction time at inlet ozone dose of 11.5 g/m3, solution pH of 11 and 30 mg/L of initial concentration of dye. The presence of radical scavenger (Tertiary Butyl Alcohol) suppressed the CRE from 98.62% to 95.4% at high pH values indicates that the indirect mechanism dominates due to the presence of hydroxyl radicals which are formed by the decomposition of ozone. The diffusive and convective mass transfer coefficients of ozone are calculated as 1.78 × 10-5 cm2/sec and 0.075 min-1. It is observed that the fraction of resistance offered by liquid is very much high compared to gas phase indicates that the ozonation is a liquid phase mass transfer controlled operation.

Experimental and theoretical studies of nuclear generation of ozone from oxygen and oxygen--sulfur hexafluoride mixtures

International Nuclear Information System (INIS)

Elsayed-Ali, H.E.; Miley, G.H.

1986-01-01

A series of experimental measurements of the yield of O 3 in nuclear-induced O 2 and O 2 -SF 6 discharges are reported. The discharges were created by bombardment with energetic particles from the 10 B(n,α) 7 Li reaction. Continuous irradiation at dose rates of 10 15 --10 17 eV cm -3 s -1 and pulsed irradiation (--10 ms FWHM) at a peak dose rate of --10 20 eV cm -3 s -1 were conducted. At the lower dose rates, the addition of SF 6 generally increased the ozone yield due to the slowing of ozone destruction by negative oxygen and ozone ions. In contrast, at the high dose rates, the ozone concentration decreased due to SF 6 suppression of atomic oxygen formation by ion--ion recombination. A numerical model was developed and tested against experimental conditions. This model indicates that the steady-state ozone concentration was limited by the reaction O - 3 +O 3 →2O 2 +O - 2 with a rate coefficient of --1 x 10 -12 cm 3 s -1 . In addition to dose rate effects, pressure and temperature effects on ozone production are discussed and methods for increasing the ozone yield are suggested

Experimental and theoretical studies of nuclear generation of ozone from oxygen and oxygen-sulfur hexafluoride mixtures

Science.gov (United States)

Elsayed-Ali, H. E.; Miley, G. H.

1986-08-01

A series of experimental measurements of the yield of O3 in nuclear-induced O2 and O2-SF6 discharges are reported. The discharges were created by bombardment with energetic particles from the 10B(n,α)7Li reaction. Continuous irradiation at dose rates of 1015-1017 eV cm-3 s-1 and pulsed irradiation (˜10 ms FWHM) at a peak dose rate of ˜1020 eV cm-3 s-1 were conducted. At the lower dose rates, the addition of SF6 generally increased the ozone yield due to the slowing of ozone destruction by negative oxygen and ozone ions. In contrast, at the high dose rates, the ozone concentration decreased due to SF6 suppression of atomic oxygen formation by ion-ion recombination. A numerical model was developed and tested against experimental conditions. This model indicates that the steady-state ozone concentration was limited by the reaction O-3+O3→2O2+O-2 with a rate coefficient of ˜1×10-12 cm3 s-1. In addition to dose rate effects, pressure and temperature effects on ozone production are discussed and methods for increasing the ozone yield are suggested.

Analysis of the Sensing Properties of a Highly Stable and Reproducible Ozone Gas Sensor Based on Amorphous In-Ga-Zn-O Thin Film.

Science.gov (United States)

Wu, Chiu-Hsien; Jiang, Guo-Jhen; Chang, Kai-Wei; Deng, Zu-Yin; Li, Yu-Ning; Chen, Kuen-Lin; Jeng, Chien-Chung

2018-01-09

In this study, the sensing properties of an amorphous indium gallium zinc oxide (a-IGZO) thin film at ozone concentrations from 500 to 5 ppm were investigated. The a-IGZO thin film showed very good reproducibility and stability over three test cycles. The ozone concentration of 60-70 ppb also showed a good response. The resistance change (Δ R ) and sensitivity ( S ) were linearly dependent on the ozone concentration. The response time ( T 90-res ), recovery time ( T 90-rec ), and time constant (τ) showed first-order exponential decay with increasing ozone concentration. The resistance-time curve shows that the maximum resistance change rate (dRg/dt) is proportional to the ozone concentration during the adsorption. The results also show that it is better to sense rapidly and stably at a low ozone concentration using a high light intensity. The ozone concentration can be derived from the resistance change, sensitivity, response time, time constant (τ), and first derivative function of resistance. However, the time of the first derivative function of resistance is shorter than other parameters. The results show that a-IGZO thin films and the first-order differentiation method are promising candidates for use as ozone sensors for practical applications.

Analysis of the Sensing Properties of a Highly Stable and Reproducible Ozone Gas Sensor Based on Amorphous In-Ga-Zn-O Thin Film