WorldWideScience

Sample records for ozone concentration variations

  1. 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.

  2. 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.

  3. [Ozone concentration distribution of urban].

    Science.gov (United States)

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

    2004-11-01

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

  4. 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.

  5. Effect of increased carbon dioxide concentrations on stratospheric ozone

    International Nuclear Information System (INIS)

    Boughner, R.E.

    1978-01-01

    During the past several years, much attention has been focused on the destruction of ozone by anthropogenic pollutants such as the nitrogen oxides and chlorofluoromethane. Little or no attention has been given to the influence on ozone of an increased carbon dioxide concentration for which a measurable growth has been observed. Increased carbon dioxide can directly affect ozone by perturbing atmospheric temperatures, which will alter ozone production, whose rate displays a fairly strong temperature dependence. This paper presents one-dimensional model results for the steady state ozone behavior when the CO 2 concentration is twice its ambient level which account for coupling between chemistry and temperature. When the CO 2 level doubled, the total ozone burden increased in relation to the ambient burden by 1.2--2.5%, depending on the vertical diffusion coefficient used. Above 30 km. In this region the relation variations were insensitive to the choice of diffusion coefficient. Below 30 km, ozone concentrations were smaller than the unperturbed values and were sensitive to the vertical diffusion profile in this region (10--30 km). Ozone decreases in the lower stratosphere because of a reduction in ozone-producing solar radiation, which results in smaller downward ozone fluxes from the region at 25--30 km relative to the flux values for the ambient atmosphere. These offsetting changes occurring in the upper and lower stratosphere act to minimize the variation in total ozone

  6. OZONE CONCENTRATION ATTRIBUTABLE PREMATURE DEATH IN POLAND

    Directory of Open Access Journals (Sweden)

    Krzysztof Skotak

    2010-03-01

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

  7. 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.

  8. 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

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

    Science.gov (United States)

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

    2017-12-01

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

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

    DEFF Research Database (Denmark)

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

    2006-01-01

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

  11. 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.

  12. 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

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

    Science.gov (United States)

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

    2018-03-29

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

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

    Science.gov (United States)

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

    2018-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Hui Zhao

    2018-03-01

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

  16. 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

  17. 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

  18. 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.

  19. 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

  20. Solar variations and their influence on trends in upper stratospheric ozone and temperature

    International Nuclear Information System (INIS)

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

    1990-10-01

    Over the past decade, knowledge of the magnitude and temporal structure of the variations in the sun's ultraviolet irradiance has increased steadily. A number of theoretical modeling studies have shown that changes in the solar ultraviolet flux during the 11-year solar cycle can have a significant effect on stratospheric ozone concentrations. With the exception of Brasseur et al., who examined a very broad range of solar flux variations, all of these studies assumed much larger changes in the ultraviolet flux than measurements now indicate. These studies either calculated the steady-state effect at solar maximum and solar minimum or assumed sinusoidal variations in the solar flux changes with time. It is now possible to narrow the uncertainty range of the expected effects on upper stratospheric ozone and temperature resulting from the 11-year solar cycle. A more accurate representation of the solar flux changes with time is used in this analysis, as compared to previous published studies. This study also evaluates the relative roles of solar flux variations and increasing concentrations of long-lived trace gases in determining the observed trends in upper stratospheric ozone and temperature. The LLNL two-dimensional chemical-radiative-transport model of the global atmosphere is used to evaluate the combined effects on the stratosphere from changes in solar ultraviolet irradiances and trace gas concentrations over the last several decades. Derived trends in upper stratospheric ozone concentrations and temperature are then compared with available analyses of ground-based and satellite measurements over this time period

  1. Distribution ozone concentration in Klang Valley using GIS approaches

    Science.gov (United States)

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

    2017-05-01

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

  2. Distribution ozone concentration in Klang Valley using GIS approaches

    International Nuclear Information System (INIS)

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

    2017-01-01

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

  3. 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.

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

    Science.gov (United States)

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

    2011-03-01

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

  5. Global distribution of total ozone and lower stratospheric temperature variations

    Directory of Open Access Journals (Sweden)

    W. Steinbrecht

    2003-01-01

    Full Text Available This study gives an overview of interannual variations of total ozone and 50 hPa temperature. It is based on newer and longer records from the 1979 to 2001 Total Ozone Monitoring Spectrometer (TOMS and Solar Backscatter Ultraviolet (SBUV instruments, and on US National Center for Environmental Prediction (NCEP reanalyses. Multiple linear least squares regression is used to attribute variations to various natural and anthropogenic explanatory variables. Usually, maps of total ozone and 50 hPa temperature variations look very similar, reflecting a very close coupling between the two. As a rule of thumb, a 10 Dobson Unit (DU change in total ozone corresponds to a 1 K change of 50 hPa temperature. Large variations come from the linear trend term, up to -30 DU or -1.5 K/decade, from terms related to polar vortex strength, up to 50 DU or 5 K (typical, minimum to maximum, from tropospheric meteorology, up to 30 DU or 3 K, or from the Quasi-Biennial Oscillation (QBO, up to 25 DU or 2.5 K. The 11-year solar cycle, up to 25 DU or 2.5 K, or El Niño/Southern Oscillation (ENSO, up to 10 DU or 1 K, are contributing smaller variations. Stratospheric aerosol after the 1991 Pinatubo eruption lead to warming up to 3 K at low latitudes and to ozone depletion up to 40 DU at high latitudes. Variations attributed to QBO, polar vortex strength, and to a lesser degree to ENSO, exhibit an inverse correlation between low latitudes and higher latitudes. Variations related to the solar cycle or 400 hPa temperature, however, have the same sign over most of the globe. Variations are usually zonally symmetric at low and mid-latitudes, but asymmetric at high latitudes. There, position and strength of the stratospheric anti-cyclones over the Aleutians and south of Australia appear to vary with the phases of solar cycle, QBO or ENSO.

  6. Are Antarctic ozone variations a manifestation of dynamics or chemistry?

    Science.gov (United States)

    Tung, K.-K.; Ko, M. K. W.; Rodriguez, J. M.; Sze, N. D.

    1986-01-01

    The existence of a reverse circulation cell with rising motion in the polar lower stratosphere is suggested as an explanation for the temporal behavior of the ozone column density in the Antarctic region. The upwelling brings ozone-poor air from below 100 mbar to the stratosphere, possibly contributing to the observed ozone decline in early spring. At the same time, the Antarctic stratosphere might contain a very low concentration of NO(x), a condition that could favor a greatly enhanced catalytic removal of O3 by halogen species. It is argued that heterogeneous processes and formation of OClO by the reaction BrO+ClO - OClO+Br before and after the polar night might help to suppress the NO(x) levels during the early spring period.

  7. 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 ...

  8. 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

  9. Human mortality effects of future concentrations of tropospheric ozone

    International Nuclear Information System (INIS)

    West, J.; Szopa, S.; Hauglustaine, D.A.

    2007-01-01

    Here we explore the effects of projected future changes in global ozone concentrations on premature human mortality, under three scenarios for 2030. We use daily surface ozone concentrations from a global atmospheric transport and chemistry model, and ozone-mortality relationships from daily time-series studies. The population-weighted annual average 8-h daily maximum ozone is projected to increase, relative to the present, in each of ten world regions under the SRES A2 scenario and the current legislation (CLE) scenario, with the largest growth in tropical regions, while decreases are projected in each region in the maximum feasible reduction (MFR) scenario. Emission reductions in the CLE scenario, relative to A2, are estimated to reduce about 190,000 premature human mortalities globally in 2030, with the most avoided mortalities in Africa. The MFR scenario will avoid about 460,000 premature mortalities relative to A2 in 2030, and 270,000 relative to CLE, with the greatest reductions in South Asia. (authors)

  10. 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)

  11. 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.

  12. 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...

  13. 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.

  14. 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.

  15. Influences of the variation in inflow to East Asia on surface ozone over Japan during 1996–2005

    Directory of Open Access Journals (Sweden)

    S. Chatani

    2011-08-01

    Full Text Available Air quality simulations in which the global chemical transport model CHASER and the regional chemical transport model WRF/chem are coupled have been developed to consider the dynamic transport of chemical species across the boundaries of the domain of the regional chemical transport model. The simulation captures the overall seasonal variations of surface ozone, but overestimates its concentration over Japanese populated areas by approximately 20 ppb from summer to early winter. It is deduced that ozone formation around Northeast China and Japan in summer is overestimated in the simulation. On the other hand, the simulation well reproduces the interannual variability and the long-term trend of observed surface ozone over Japan. Sensitivity experiments have been performed to investigate the influence of the variation in inflow to East Asia on the interannual variability and the long-term trend of surface ozone over Japan during 1996–2005. The inflow defined in this paper includes the recirculation of species with sources within the East Asian region as well as the transport of species with sources out of the East Asian region. Results of sensitivity experiments suggest that inflow to East Asia accounts for approximately 30 % of the increasing trend of surface ozone, whereas it has much less influence on the interannual variability of observed surface ozone compared to meteorological processes within East Asia.

  16. Growth of soybean at future tropospheric ozone concentrations decreases canopy evapotranspiration and soil water depletion

    Energy Technology Data Exchange (ETDEWEB)

    Bernacchi, Carl J., E-mail: bernacch@illinois.edu [Global Change and Photosynthesis Research Unit, United States Department of Agriculture Agricultural Research Service, Urbana, IL 61801 (United States); Institute for Genomic Biology and Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Leakey, Andrew D.B. [Institute for Genomic Biology and Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Kimball, Bruce A. [USDA-ARS US Arid-Land Agricultural Research Center, 21881 N. Cardon Lane, Maricopa, AZ 85238 (United States); Ort, Donald R. [Global Change and Photosynthesis Research Unit, United States Department of Agriculture Agricultural Research Service, Urbana, IL 61801 (United States); Institute for Genomic Biology and Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States)

    2011-06-15

    Tropospheric ozone is increasing in many agricultural regions resulting in decreased stomatal conductance and overall biomass of sensitive crop species. These physiological effects of ozone forecast changes in evapotranspiration and thus in the terrestrial hydrological cycle, particularly in intercontinental interiors. Soybean plots were fumigated with ozone to achieve concentrations above ambient levels over five growing seasons in open-air field conditions. Mean season increases in ozone concentrations ([O{sub 3}]) varied between growing seasons from 22 to 37% above background concentrations. The objective of this experiment was to examine the effects of future [O{sub 3}] on crop ecosystem energy fluxes and water use. Elevated [O{sub 3}] caused decreases in canopy evapotranspiration resulting in decreased water use by as much as 15% in high ozone years and decreased soil water removal. In addition, ozone treatment resulted in increased sensible heat flux in all years indicative of day-time increase in canopy temperature of up to 0.7 deg. C. - Highlights: > Globally, tropospheric ozone is currently and will likely continue to increase into the future. > We examine the impact of elevated ozone on water use by soybean at the SoyFACE research facility. > High ozone grown soybean had reduced rates of evapotranspiration and higher soil moisture. > Increases in ozone have the potential to impact the hydrologic cycle where these crops are grown. - Soybean grown in elevated concentrations of ozone is shown to evapotranspire less water compared with soybean canopies grown under current atmospheric conditions.

  17. Growth of soybean at future tropospheric ozone concentrations decreases canopy evapotranspiration and soil water depletion

    International Nuclear Information System (INIS)

    Bernacchi, Carl J.; Leakey, Andrew D.B.; Kimball, Bruce A.; Ort, Donald R.

    2011-01-01

    Tropospheric ozone is increasing in many agricultural regions resulting in decreased stomatal conductance and overall biomass of sensitive crop species. These physiological effects of ozone forecast changes in evapotranspiration and thus in the terrestrial hydrological cycle, particularly in intercontinental interiors. Soybean plots were fumigated with ozone to achieve concentrations above ambient levels over five growing seasons in open-air field conditions. Mean season increases in ozone concentrations ([O 3 ]) varied between growing seasons from 22 to 37% above background concentrations. The objective of this experiment was to examine the effects of future [O 3 ] on crop ecosystem energy fluxes and water use. Elevated [O 3 ] caused decreases in canopy evapotranspiration resulting in decreased water use by as much as 15% in high ozone years and decreased soil water removal. In addition, ozone treatment resulted in increased sensible heat flux in all years indicative of day-time increase in canopy temperature of up to 0.7 deg. C. - Highlights: → Globally, tropospheric ozone is currently and will likely continue to increase into the future. → We examine the impact of elevated ozone on water use by soybean at the SoyFACE research facility. → High ozone grown soybean had reduced rates of evapotranspiration and higher soil moisture. → Increases in ozone have the potential to impact the hydrologic cycle where these crops are grown. - Soybean grown in elevated concentrations of ozone is shown to evapotranspire less water compared with soybean canopies grown under current atmospheric conditions.

  18. 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.

  19. Variational data assimilation for the optimized ozone initial state and the short-time forecasting

    Directory of Open Access Journals (Sweden)

    S.-Y. Park

    2016-03-01

    Full Text Available In this study, we apply the four-dimensional variational (4D-Var data assimilation to optimize initial ozone state and to improve the predictability of air quality. The numerical modeling systems used for simulations of atmospheric condition and chemical formation are the Weather Research and Forecasting (WRF model and the Community Multiscale Air Quality (CMAQ model. The study area covers the capital region of South Korea, where the surface measurement sites are relatively evenly distributed. The 4D-Var code previously developed for the CMAQ model is modified to consider background error in matrix form, and various numerical tests are conducted. The results are evaluated with an idealized covariance function for the appropriateness of the modified codes. The background error is then constructed using the NMC method with long-term modeling results, and the characteristics of the spatial correlation scale related to local circulation are analyzed. The background error is applied in the 4D-Var research, and a surface observational assimilation is conducted to optimize the initial concentration of ozone. The statistical results for the 12 h assimilation periods and the 120 observatory sites show a 49.4 % decrease in the root mean squared error (RMSE, and a 59.9 % increase in the index of agreement (IOA. The temporal variation of spatial distribution of the analysis increments indicates that the optimized initial state of ozone concentration is transported to inland areas by the clockwise-rotating local circulation during the assimilation windows. To investigate the predictability of ozone concentration after the assimilation window, a short-time forecasting is carried out. The ratios of the RMSE (root mean squared error with assimilation versus that without assimilation are 8 and 13 % for the +24 and +12 h, respectively. Such a significant improvement in the forecast accuracy is obtained solely by using the optimized initial state. The potential

  20. 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.

  1. 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...

  2. 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.

  3. 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)

  4. An assessment of ground-level ozone concentrations in the Athabasca oil sands region

    International Nuclear Information System (INIS)

    1997-01-01

    Syncrude and Suncor have plans to develop new oil sands leases and to increase crude oil and bitumen recovery in the Athabasca oil sands region. A first air quality assessment was prepared as part of the Alberta Energy and Utilities Board application, in order to evaluate the emissions and potential impacts associated with the development. The Pembina Institute raised several issues with respect to potential future changes in ambient ozone levels as a result of the Aurora Mine operations. In response to these concerns, another more rigorous assessment was conducted to predict future ground-level ozone concentrations in the Fort McMurray area. This report includes: (1) ambient air quality guidelines for ozone, (2) emissions inventory for dispersion modelling, (3) dispersion modelling methodology, and (4) predicted ambient ozone concentrations. Ground level ozone (O 3 ) concentrations result from anthropogenically produced ozone, and from naturally occurring ozone. Ozone is not directly emitted to the atmosphere from industrial sources, but is formed as a result of chemical reactions between NO x and VOCs, which are emitted from industrial sources within the Athabasca oil sands region. NO x and VOC emissions associated with the Aurora Mine operation are predicted to increase hourly average ozone concentrations in the Fort McMurray area by only 0.001 ppm. 17 refs., 18 tabs., 5 figs

  5. 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)

  6. Concentration variation of radon in the room

    International Nuclear Information System (INIS)

    Komaruzaman Mohd Noor; Haziman Hassan; Rosli Mahat; Yusof Md Amin

    1995-01-01

    The study was carried out to determine the variation of radon concentration in the room. Radon detector used was solid nuclear tracks detector (SSNTD) LR-115. From this result, suitable points to make radon measurement was determined

  7. 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.

  8. 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

  9. 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

  10. Influence of isentropic transport on seasonal ozone variations in the lower stratosphere and subtropical upper troposphere

    Science.gov (United States)

    Jing, P.; Cunnold, D. M.; Yang, E.-S.; Wang, H.-J.

    2005-01-01

    The isentropic cross-tropopause ozone transport has been estimated in both hemispheres in 1999 based on the potential vorticity mapping of Stratospheric Aerosol and Gas Experiment 11 ozone measurements and contour advection calculations using the NASA Goddard Space Flight Center Global and Modeling Assimilation Office analysis. The estimated net isentropic stratosphere-to-troposphere ozone flux is approx.118 +/- 61 x 10(exp9)kg/yr globally within the layer between 330 and 370 K in 1999; 60% of it is found in the Northern Hemisphere, and 40% is found in the Southern Hemisphere. The monthly average ozone fluxes are strongest in summer and weakest in winter in both hemispheres. The seasonal variations of ozone in the lower stratosphere (LS) and upper troposphere (UT) have been analyzed using ozonesonde observations from ozonesonde stations in the extratropics and subtropics, respectively. It is shown that observed ozone levels increase in the UT over subtropical ozonesonde stations and decrease in the LS over extratropical stations in late spring/early summer and that the ozone increases in the summertime subtropical UT are unlikely to be explained by photochemical ozone production and diabatic transport alone. We conclude that isentropic transport is a significant contributor to ozone levels in the subtropical upper troposphere, especially in summer.

  11. Surface ozone at Nam Co in the inland Tibetan Plateau: variation, synthesis comparison and regional representativeness

    Science.gov (United States)

    Yin, Xiufeng; Kang, Shichang; de Foy, Benjamin; Cong, Zhiyuan; Luo, Jiali; Zhang, Lang; Ma, Yaoming; Zhang, Guoshuai; Rupakheti, Dipesh; Zhang, Qianggong

    2017-09-01

    Ozone is an important pollutant and greenhouse gas, and tropospheric ozone variations are generally associated with both natural and anthropogenic processes. As one of the most pristine and inaccessible regions in the world, the Tibetan Plateau has been considered as an ideal region for studying processes of the background atmosphere. Due to the vast area of the Tibetan Plateau, sites in the southern, northern and central regions exhibit different patterns of variation in surface ozone. Here, we present continuous measurements of surface ozone mixing ratios at Nam Co Station over a period of ˜ 5 years (January 2011 to October 2015), which is a background site in the inland Tibetan Plateau. An average surface ozone mixing ratio of 47.6 ± 11.6 ppb (mean ± standard deviation) was recorded, and a large annual cycle was observed with maximum ozone mixing ratios in the spring and minimum ratios during the winter. The diurnal cycle is characterized by a minimum in the early morning and a maximum in the late afternoon. Nam Co Station represents a background region where surface ozone receives negligible local anthropogenic emissions inputs, and the anthropogenic contribution from South Asia in spring and China in summer may affect Nam Co Station occasionally. Surface ozone at Nam Co Station is mainly dominated by natural processes involving photochemical reactions, vertical mixing and downward transport of stratospheric air mass. Model results indicate that the study site is affected differently by the surrounding areas in different seasons: air masses from the southern Tibetan Plateau contribute to the high ozone levels in the spring, and enhanced ozone levels in the summer are associated with air masses from the northern Tibetan Plateau. By comparing measurements at Nam Co Station with those from other sites on the Tibetan Plateau, we aim to expand the understanding of ozone cycles and transport processes over the Tibetan Plateau. This work may provide a

  12. 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.

  13. 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.

  14. 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

  15. 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

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. Tropospheric ozone variations in polar regions; Troposphaerische Ozonvariationen in Polarregionen

    Energy Technology Data Exchange (ETDEWEB)

    Wessel, S.

    1997-08-01

    An extensive analysis for the description of chemical and dynamical processes during tropospheric ozone minima in the Arctic and Antarctic was carried out in this work. One main task was the analysis of the source regions of tropospheric ozone destruction and the following transport of ozone depleted air masses to the measuring site. Furtheron the ozone destruction mechanism itself should be examined as well as the efficiency of heterogeneous reactions for the regeneration of non-reative bromine compounds, which seems to be necessary because bromine may be the key component in the destruction of tropospheric ozone in polar regions. (orig./KW) [Deutsch] In der vorliegenden Arbeit wurde eine umfangreiche Analyse zur Beschreibung der chemischen und dynamischen Prozesse waehrend troposphaerischer Ozonminima in der Arktis und Antarktis durchgefuehrt. Ziel war es, die Quellregion des Ozonabbaus sowie den ausloesenden ozonabbauenden Mechanismus zu benennen, die Effizienz heterogener Reaktionen zur Regenerierung nichtreaktiver Bromverbindungen waehrend des Ozonabbaus zu ermitteln und den Transport der ozonarmen Luftmassen zum Messort zu untersuchen. (orig./KW)

  1. 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

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

    Directory of Open Access Journals (Sweden)

    Yuehua Wu

    2015-04-01

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

  3. 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.

  4. 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

  5. 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

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

    Indian Academy of Sciences (India)

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

  7. The effect of increased ozone concentrations in the air on selected aspects of rat reproduction.

    Science.gov (United States)

    Jedlińska-Krakowska, M; Gizejewski, Z; Dietrich, G J; Jakubowski, K; Glogowski, J; Penkowski, A

    2006-01-01

    Five-month-old male rates were exposed to 0.5 ppm ozone for 50 days, 5 hours a day. A week before the completion of ozone exposure, a biological test was performed to determine the fertilization rate and the survival rate of newborns in both ozone-exposed and control animals. After 50 days, the rats were sacrificed with an overdose of halotane, and testes were collected to assess the morphology and motility of spermatozoa. Neither the morphology of spermatozoa nor motility parameters determined by the CASA (computer-assisted sperm analysis) system showed statistically significant differences between ozone-exposed and control males. The number of successful matings and the survival rate of newborns per litter within one year postpartum were also similar in both groups. However, sperm concentration was by 17% lower in ozone-exposed rats, compared with the control animals.

  8. Tropospheric ozone annual variation and possible troposphere-stratosphere coupling in the Arctic and Antarctic as derived from ozone soundings at Resolute and Amundsen-Scott stations

    Energy Technology Data Exchange (ETDEWEB)

    Gruzdev, A.N.; Sitnov, S.A. (Russian Academy of Sciences, Moscow (Russian Federation). Inst. of Atmospheric Physics)

    1993-01-01

    The tropospheric ozone annual variation in the northern and southern polar regions is analyzed from ozone sounding data obtained at Resolute during a 15-year period and Amundsen-Scott during a 7-year period. The phase of ozone annual variation above Resolute changes (increases) gradually from the stratosphere across the tropopause to the middle troposphere. Unlike this, the phase of the Antarctic ozone annual harmonic has a discontinuity in the layer of the changing tropopause level, so that the annual harmonic in the upper troposphere, lower stratosphere is 4-to-5 months out of phase (earlier) to that above and beneath. Above both the Arctic and Antarctic stations, the ozone mixing ratio and its vertical gradient evolve in a similar manner in the wide layer from the lower stratosphere to the middle troposphere. This likely points out that ozone in this layer is controlled from above. An indication of the stratospheric-tropospheric ozone exchange above Resolute is noted from mid-winter to spring. The analysis of columnar tropospheric ozone changes gives a lower estimate of the cross-tropopause ozone flux up to 5x10[sup 10] mol cm[sup -2] s[sup -1]. Above the South Pole, the cross-tropopause ozone flux is not usually large. There is also some evidence that early in the spring, when the stratospheric ozone 'hole' is developed, the stratospheric-tropospheric exchange conducts the influence of the 'hole' into the upper troposphere, where the integrated ozone destruction is estimated to be 8x10[sup 10] mol cm[sup -2] s[sup -1]. Correlation analysis gives no ozone-tropopause correlation in the Antarctic in winter, while in other seasons as well as during all seasons in the Arctic, there are negative correlation peaks just above the tropopause. (19 refs., 6 figs.).

  9. 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.

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

    Indian Academy of Sciences (India)

    can affect climate via the “atmospheric greenhouse effect” and the challenging task for scientists is to find out the factors that influence the presence of these trace gases. Ozone has a major significance, as in stratosphere in the protection of the earth from the sun's harmful ultraviolet radiation so in tro- posphere in climate ...

  11. Seasonal variations of indoor radon concentrations

    International Nuclear Information System (INIS)

    Majborn, B.

    1990-01-01

    Seasonal variations of indoor radon concentrations have been studied in a cluster of 10 single-family houses. Eight of the houses are of a similar construction with slab-on-grade foundations. The remaining two houses have different substructures, one of them having a crawl space, and the other having partly a basement and partly a crawl space. A 'normal' seasonal variation of the radon concentration with a maximum in winter and a minimum in summer was observed in most of the houses. In these houses the variation showed a strong correlation with the indoor-outdoor temperature difference on a 2-month basis. However, deviating seasonal variations were observed in some of the houses, notably in the two houses having different substructures. This paper reports that a re-examination of the data obtained in a previous study indicates that winter/summer ratios of indoor radon concentrations in Danish houses depend on the house substructure. The mean winter/summer ratios were about 2.1 for houses with slab-on-grade foundations, 1.5 for houses having a basement, and 1.0 for houses with a crawl space (geometric mean values). However, a study with more houses in each substructure category will be needed to show whether or not the indicated differences are generally valid for Danish houses

  12. 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.

  13. Measures of ozone concentrations using passive sampling in forests of South Western Europe

    Energy Technology Data Exchange (ETDEWEB)

    Sanz, M.J. [Fundacion CEAM, Charles R. Darwin 14, Parc Tecnologic, E-46980 Paterna, Valencia (Spain)]. E-mail: mjose@ceam.es; Calatayud, V. [Fundacion CEAM, Charles R. Darwin 14, Parc Tecnologic, E-46980 Paterna, Valencia (Spain); Sanchez-Pena, G. [Servicio de Proteccion de los Montes contra Agentes Nocivos, Direccion General para la Biodiversidad, Ministerio de Medio Ambiente, Gran Via de San Francisco, 4, E-28005, Madrid (Spain)

    2007-02-15

    Ambient ozone concentrations were measured with passive samplers in the framework of the EU and UN/ECE Level II forest monitoring programme. Data from France, Italy, Luxembourg, Spain and Switzerland are reported for 2000-2002, covering the period from April to September. The number of plots increased from 67 in 2000 to 83 in 2002. The year 2001 experienced the highest ozone concentrations, reflecting more stable summer meteorological conditions. Average 6-month ozone concentrations above 45 ppb were measured this year in 40.3% of the plots, in contrast with the less than 21% measured in the other 2 years. Gradients of increasing ozone levels were observed from North to South and with altitude. Comments are made on the regional trends and on the time frame of the higher ozone episodes. Also, some recommendations enabling a better comparison between plots are provided. - Ozone concentrations in forested areas of SW Europe during the period 2000-2002 showed highest values in 2001, as well as a tendency to increase towards the South and with altitude.

  14. Measures of ozone concentrations using passive sampling in forests of South Western Europe

    International Nuclear Information System (INIS)

    Sanz, M.J.; Calatayud, V.; Sanchez-Pena, G.

    2007-01-01

    Ambient ozone concentrations were measured with passive samplers in the framework of the EU and UN/ECE Level II forest monitoring programme. Data from France, Italy, Luxembourg, Spain and Switzerland are reported for 2000-2002, covering the period from April to September. The number of plots increased from 67 in 2000 to 83 in 2002. The year 2001 experienced the highest ozone concentrations, reflecting more stable summer meteorological conditions. Average 6-month ozone concentrations above 45 ppb were measured this year in 40.3% of the plots, in contrast with the less than 21% measured in the other 2 years. Gradients of increasing ozone levels were observed from North to South and with altitude. Comments are made on the regional trends and on the time frame of the higher ozone episodes. Also, some recommendations enabling a better comparison between plots are provided. - Ozone concentrations in forested areas of SW Europe during the period 2000-2002 showed highest values in 2001, as well as a tendency to increase towards the South and with altitude

  15. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-09-01

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

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

    Directory of Open Access Journals (Sweden)

    Y. C. Lee

    2014-08-01

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

  18. 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.

  19. 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

  20. Surface ozone at Nam Co in the inland Tibetan Plateau: variation, synthesis comparison and regional representativeness

    Directory of Open Access Journals (Sweden)

    X. Yin

    2017-09-01

    Full Text Available Ozone is an important pollutant and greenhouse gas, and tropospheric ozone variations are generally associated with both natural and anthropogenic processes. As one of the most pristine and inaccessible regions in the world, the Tibetan Plateau has been considered as an ideal region for studying processes of the background atmosphere. Due to the vast area of the Tibetan Plateau, sites in the southern, northern and central regions exhibit different patterns of variation in surface ozone. Here, we present continuous measurements of surface ozone mixing ratios at Nam Co Station over a period of  ∼ 5 years (January 2011 to October 2015, which is a background site in the inland Tibetan Plateau. An average surface ozone mixing ratio of 47.6 ± 11.6 ppb (mean ± standard deviation was recorded, and a large annual cycle was observed with maximum ozone mixing ratios in the spring and minimum ratios during the winter. The diurnal cycle is characterized by a minimum in the early morning and a maximum in the late afternoon. Nam Co Station represents a background region where surface ozone receives negligible local anthropogenic emissions inputs, and the anthropogenic contribution from South Asia in spring and China in summer may affect Nam Co Station occasionally. Surface ozone at Nam Co Station is mainly dominated by natural processes involving photochemical reactions, vertical mixing and downward transport of stratospheric air mass. Model results indicate that the study site is affected differently by the surrounding areas in different seasons: air masses from the southern Tibetan Plateau contribute to the high ozone levels in the spring, and enhanced ozone levels in the summer are associated with air masses from the northern Tibetan Plateau. By comparing measurements at Nam Co Station with those from other sites on the Tibetan Plateau, we aim to expand the understanding of ozone cycles and transport processes over the Tibetan Plateau

  1. Mexico City ozone concentrations as a function of readily-available meteorological parameters

    International Nuclear Information System (INIS)

    Brown, M.J.

    1994-01-01

    Daily maximum ozone concentrations measured at four sites within the Mexico City basin during the winter months are plotted as functions of different meteorological parameters that are routinely measured at surface stations. We found that ozone concentrations are most strongly correlated to the increase in daytime temperature and the maximum daytime wind speed. We also discovered that high ozone values at the sites in the southern end of the basin occur when winds come out of the northeast. In contrast, wind direction was found to be uncorrelated with high ozone values at the northern sites. From straightforward combinations of the meteorological variables, we derived some simple rules for estimating lower and upper bounds on the ozone concentration. Scatter in the data was too long to give significance to best-fit equations and statistics. Additionally, a small rawinsonde data set was used to investigate ozone's dependence on boundary-layer height and near-surface temperature gradient. Results were inconclusive, however, due to the small size of the data set

  2. 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.

  3. 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.

  4. 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)

  5. 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

  6. 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.

  7. Variations of surface ozone at Ieodo Ocean Research Station in the East China Sea and the influence of Asian outflows

    Science.gov (United States)

    Han, J.; Shin, B.; Lee, M.; Hwang, G.; Kim, J.; Shim, J.; Lee, G.; Shim, C.

    2015-11-01

    Ieodo Ocean Research Station (IORS), a research tower (~ 40 m a.s.l.) for atmospheric and oceanographic observations, is located in the East China Sea (32.07° N, 125.10° E). The IORS is almost equidistant from South Korea, China, and Japan and, therefore, it is an ideal place to observe Asian outflows without local emission effects. The seasonal variation of ozone was distinct, with a minimum in August (37 ppbv) and two peaks in April and October (62 ppbv), and was largely affected by the seasonal wind pattern over east Asia. At IORS, six types of air masses were distinguished with different levels of O3 concentrations by the cluster analysis of backward trajectories. Marine air masses from the Pacific Ocean represent a relatively clean background air with a lowest ozone level of 32 ppbv, which was most frequently observed in summer (July-August). In spring (March-April) and winter (December-February), the influence of Chinese outflows was dominant with higher ozone concentrations of 62 and 49 ppbv, respectively. This study confirms that the influence of Chinese outflows was the main factor determining O3 levels at IORS and its extent was dependent on meteorological state, particularly at a long-term scale.

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

    Directory of Open Access Journals (Sweden)

    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.

  9. 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.

  10. Origins of Tropospheric Ozone Interannual Variation (IAV) over Reunion: A Model Investigation

    Science.gov (United States)

    Liu, Junhua; Rodriguez, Jose M.; Thompson, Anne M.; Logan, Jennifer A.; Douglass, Anne R.; Olsen, Mark A.; Steenrod, Stephen D.; Posny, Francoise

    2016-01-01

    Observations from long-term ozonesonde measurements show robust variations and trends in the evolution of ozone in the middle and upper troposphere over Reunion Island (21.1 degrees South Latitude, 55.5 degrees East Longitude) in June-August. Here we examine possible causes of the observed ozone variation at Reunion Island using hindcast simulations by the stratosphere-troposphere Global Modeling Initiative chemical transport model for 1992-2014, driven by assimilated Modern-Era Retrospective Analysis for Research and Applications (MERRA) meteorological fields. Reunion Island is at the edge of the subtropical jet, a region of strong stratospheric-tropospheric exchange. Our analysis implies that the large interannual variation (IAV) of upper tropospheric ozone over Reunion is driven by the large IAV of the stratospheric influence. The IAV of the large-scale, quasi-horizontal wind patterns also contributes to the IAV of ozone in the upper troposphere. Comparison to a simulation with constant emissions indicates that increasing emissions do not lead to the maximum trend in the middle and upper troposphere over Reunion during austral winter implied by the sonde data. The effects of increasing emission over southern Africa are limited tothe lower troposphere near the surface in August-September.

  11. 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

  12. 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

  13. 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

  14. 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...

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

    Science.gov (United States)

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

    2014-09-01

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

  16. Projecting future summer mortality due to ambient ozone concentration and temperature changes

    Science.gov (United States)

    Lee, Jae Young; Lee, Soo Hyun; Hong, Sung-Chul; Kim, Ho

    2017-05-01

    Climate change is known to affect the human health both directly by increased heat stress and indirectly by altering environments, particularly by altering the rate of ambient ozone formation in the atmosphere. Thus, the risks of climate change may be underestimated if the effects of both future temperature and ambient ozone concentrations are not considered. This study presents a projection of future summer non-accidental mortality in seven major cities of South Korea during the 2020s (2016-2025) and 2050s (2046-2055) considering changes in temperature and ozone concentration, which were predicted by using the HadGEM3-RA model and Integrated Climate and Air Quality Modeling System, respectively. Four Representative Concentration Pathway (RCP) scenarios (RCP 2.6, 4.5, 6.0, and 8.5) were considered. The result shows that non-accidental summer mortality will increase by 0.5%, 0.0%, 0.4%, and 0.4% in the 2020s, 1.9%, 1.5%, 1.2%, and 4.4% in the 2050s due to temperature change compared to the baseline mortality during 2001-2010, under RCP 2.6, 4.5, 6.0, and 8.5, respectively, whereas the mortality will increase by 0.0%, 0.5%, 0.0%, and 0.5% in the 2020s, and 0.2%, 0.2%, 0.4%, and 0.6% in the 2050s due to ozone concentration change. The projection result shows that the future summer morality in South Korea is increased due to changes in both temperature and ozone, and the magnitude of ozone-related increase is much smaller than that of temperature-related increase, especially in the 2050s.

  17. 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.

  18. 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.

  19. 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...

  20. 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.

  1. 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.

  2. Increasing surface ozone concentrations in the background atmosphere of Southern China, 1994–2007

    Directory of Open Access Journals (Sweden)

    T. Wang

    2009-08-01

    Full Text Available Tropospheric ozone is of great importance with regard to air quality, atmospheric chemistry, and climate change. In this paper we report the first continuous record of surface ozone in the background atmosphere of South China. The data were obtained from 1994 to 2007 at a coastal site in Hong Kong, which is strongly influenced by the outflow of Asian continental air during the winter and the inflow of maritime air from the subtropics in the summer. Three methods are used to derive the rate of change in ozone. A linear fit to the 14-year record shows that the ozone concentration increased by 0.58 ppbv/yr, whereas comparing means in years 1994–2000 and 2001–2007 gives an increase of 0.87 ppbv/yr for a 7-year period. The ozone changes in air masses from various source regions are also examined. Using local wind and carbon monoxide (CO data to filter out local influence, we find that ozone increased by 0.94 ppbv/yr from 1994–2000 to 2001–2007 in air masses from Eastern China, with similar changes in the other two continent-influenced air-mass groups, but no statistically significant change in the marine air. An examination of the nitrogen dioxide (NO2 column obtained from GOME and SCIAMACHY reveals an increase in atmospheric NO2 in China's three fastest developing coastal regions, whereas NO2 in other parts of Asia decreased during the same period, and no obvious trend over the main shipping routes in the South China Sea was indicated. Thus the observed increase in background ozone in Hong Kong is most likely due to the increased emissions of NO2 (and possibly volatile organic compounds (VOCs as well in the upwind coastal regions of mainland China. The CO data at Hok Tsui showed less definitive changes compared to the satellite NO2 column. The increase in background ozone likely made a strong contribution (81% to the rate of increase in "total ozone" at an urban site in Hong Kong

  3. 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.

  4. Possible variations in atmospheric ozone related to the eleven year solar cycle

    International Nuclear Information System (INIS)

    Penner, J.E.; Chang, J.S.

    1978-07-01

    Changes in ozone, temperature, and other minor constituents resulting from eleven year variations in the solar flux between 180 and 340 nm are presented. Results were computed using a one-dimensional time dependent model that allows for all major feedbacks and time delays which may result from changing photolysis rates in the O/sub x/--NO/sub x/--HO/sub x/--ClO/sub x/ system. Since the 1950's the chlorine content of the stratosphere has been increasing. The effect of this increase on ozone variability during the last two solar cycles is analyzed. Expected variations in O 3 and temperature resulting from changes in the uv flux are compared to available measurements

  5. 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.

  6. 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

  7. 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...

  8. 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

  9. 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)

  10. Seasonal variation of ozone deposition to a tropical rain forest in southwest Amazonia

    Directory of Open Access Journals (Sweden)

    U. Rummel

    2007-10-01

    Full Text Available Within the project EUropean Studies on Trace gases and Atmospheric CHemistry as a contribution to Large-scale Biosphere-atmosphere experiment in Amazonia (LBA-EUSTACH, we performed tower-based eddy covariance measurements of O3 flux above an Amazonian primary rain forest at the end of the wet and dry season. Ozone deposition revealed distinct seasonal differences in the magnitude and diel variation. In the wet season, the rain forest was an effective O3 sink with a mean daytime (midday maximum deposition velocity of 2.3 cm s−1, and a corresponding O3 flux of −11 nmol m−2 s−1. At the end of the dry season, the ozone mixing ratio was about four times higher (up to maximum values of 80 ppb than in the wet season, as a consequence of strong regional biomass burning activity. However, the typical maximum daytime deposition flux was very similar to the wet season. This results from a strong limitation of daytime O3 deposition due to reduced plant stomatal aperture as a response to large values of the specific humidity deficit. As a result, the average midday deposition velocity in the dry burning season was only 0.5 cm s−1. The large diel ozone variation caused large canopy storage effects that masked the true diel variation of ozone deposition mechanisms in the measured eddy covariance flux, and for which corrections had to be made. In general, stomatal aperture was sufficient to explain the largest part of daytime ozone deposition. However, during nighttime, chemical reaction with nitrogen monoxide (NO was found to contribute substantially to the O3 sink in the rain forest canopy. Further contributions were from non-stomatal plant uptake and other processes that could not be clearly identified.

    Measurements, made simultaneously on a 22 years old cattle pasture enabled the spatially and temporally direct comparison of O3

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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.

  16. 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)

  17. 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

  18. Influence of inter-annual variations of stratospheric dynamics in model simulations of ozone losses by aircraft emissions

    Energy Technology Data Exchange (ETDEWEB)

    Jadin, E.A. [Central Aerological Observatory, Dolgoprudny (Russian Federation)

    1997-12-31

    The questions of model predictions of aircraft emission impacts on the ozone variations are considered. Using the NMC data it is shown that the stratospheric circulation underwent the abrupt transition to a new regime in summer 1980. The strong correlations are found between the monthly mean total ozone and stratospheric angular momentum anomalies during 1979-1991. The natural long-term changes of transport processes are necessary to take into account in model simulations of anthropogenic impacts on the ozone layer. (author) 12 refs.

  19. Influence of inter-annual variations of stratospheric dynamics in model simulations of ozone losses by aircraft emissions

    Energy Technology Data Exchange (ETDEWEB)

    Jadin, E A [Central Aerological Observatory, Dolgoprudny (Russian Federation)

    1998-12-31

    The questions of model predictions of aircraft emission impacts on the ozone variations are considered. Using the NMC data it is shown that the stratospheric circulation underwent the abrupt transition to a new regime in summer 1980. The strong correlations are found between the monthly mean total ozone and stratospheric angular momentum anomalies during 1979-1991. The natural long-term changes of transport processes are necessary to take into account in model simulations of anthropogenic impacts on the ozone layer. (author) 12 refs.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

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

  1. 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

  2. Seasonal variation in heavy metal concentration in mangrove foliage

    Digital Repository Service at National Institute of Oceanography (India)

    Untawale, A.G.; Wafar, S.; Bhosle, N.B.

    Seasonal variation in the concentration of some heavy metals in the leaves of seven species of mangrove vegetation from Goa, revealed that maximum concentration of iron and manganese occurs during the monsoon season without any significant toxic...

  3. Seasonal Variation in Human Salivary Cortisol Concentration

    DEFF Research Database (Denmark)

    Persson, Roger; Garde, Anne Helene; Hansen, Åse Marie

    2008-01-01

    Measurement of cortisol concentration can contribute important information about an individual's ability to adjust to various environmental demands of both physical and psychosocial origin. However, one uncertainty that affects the possibilities of correctly interpreting and designing field studies...... is the lack of observations of the impact of seasonal changes on cortisol excretion. For this reason, the month-to-month changes in diurnal cortisol concentration, the awakening cortisol response (ACR), maximum morning concentration, and fall during the day were studied in a group of 24 healthy men and women...... 32 to 61 yrs of age engaged in active work. On one workday for 12 consecutive months, participants collected saliva at four time points for determination of cortisol: at awakening, +30 min, +8 h, and at 21:00 h. Data were analyzed by a repeated measures design with month (12 levels) and time...

  4. 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

  5. Comparison of predicted and measured variations of indoor radon concentration

    International Nuclear Information System (INIS)

    Arvela, H.; Voutilainen, A.; Maekelaeinen, I.; Castren, O.; Winqvist, K.

    1988-01-01

    Prediction of the variations of indoor radon concentration were calculated using a model relating indoor radon concentration to radon entry rate, air infiltration and meteorological factors. These calculated variations have been compared with seasonal variations of 33 houses during 1-4 years, with winter-summer concentration ratios of 300 houses and the measured diurnal variation. In houses with a slab in ground contact the measured seasonal variations are quite often in agreement with variations predicted for nearly pure pressure difference driven flow. The contribution of a diffusion source is significant in houses with large porous concrete walls against the ground. Air flow due to seasonally variable thermal convection within eskers strongly affects the seasonal variations within houses located thereon. Measured and predicted winter-summer concentration ratios demonstrate that, on average, the ratio is a function of radon concentration. The ratio increases with increasing winter concentration. According to the model the diurnal maximum caused by a pressure difference driven flow occurs in the morning, a finding which is in agreement with the measurements. The model presented can be used for differentiating between factors affecting radon entry into houses. (author)

  6. Solar cycle variations of stratospheric ozone and temperature in simulations of a coupled chemistry-climate model

    Directory of Open Access Journals (Sweden)

    J. Austin

    2007-01-01

    Full Text Available The results from three 45-year simulations of a coupled chemistry climate model are analysed for solar cycle influences on ozone and temperature. The simulations include UV forcing at the top of the atmosphere, which includes a generic 27-day solar rotation effect as well as the observed monthly values of the solar fluxes. The results are analysed for the 27-day and 11-year cycles in temperature and ozone. In accordance with previous results, the 27-day cycle results are in good qualitative agreement with observations, particularly for ozone. However, the results show significant variations, typically a factor of two or more in sensitivity to solar flux, depending on the solar cycle. In the lower and middle stratosphere we show good agreement also between the modelled and observed 11-year cycle results for the ozone vertical profile averaged over low latitudes. In particular, the minimum in solar response near 20 hPa is well simulated. In comparison, experiments of the model with fixed solar phase (solar maximum/solar mean and climatological sea surface temperatures lead to a poorer simulation of the solar response in the ozone vertical profile, indicating the need for variable phase simulations in solar sensitivity experiments. The role of sea surface temperatures and tropical upwelling in simulating the ozone minimum response are also discussed.

  7. 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.

  8. Variations of Rn-222 concentration in the Bratislava air

    International Nuclear Information System (INIS)

    Holy, K.; Bohm, R.; Polaskova, A.

    1996-01-01

    222 Rn is produced by alpha decay of 222 Ra in roil. A small fraction of totally produced 222 Rn escapes from coil particles into soil air. Then 222 Rn is transported predominantly by molecular diffusion into outdoor atmosphere. The radon concentration in the outdoor atmosphere is not stable. It varies irregularly depending on meteorological conditions. However there were found out regular daily and remand variations of 222 Rn concentration in outdoor atmosphere. These variations were measured in numerous works and results are summarized f.e. in work of Gesell. A simple model described the annual variations of 222 Rn concentration war published by Minato. A mathematical analysis of daily course of 222 Rn concentration in outdoor atmosphere was realized by Garzon et al. Some results of our study of 222 Rn variations in outdoor atmosphere of Bratislava are shown in this report. (author)

  9. 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

  10. 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

  11. 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...

  12. Impacts of decadal variations in natural emissions due to land-cover changes on ozone production in southern China

    Directory of Open Access Journals (Sweden)

    Mengmeng Li

    2015-09-01

    Full Text Available The decadal variations in emissions of high-reactivity biogenic volatile organics (BVOCs, as a result of land-cover changes, could significantly impact ozone (O3 production. In this study, the Weather Research and Forecasting/Chemistry (WRF/Chem modelling system, coupled with dynamic vegetation data sets derived from Moderate Resolution Imaging Spectroradiometer (MODIS, 2001–2012 and Advanced Very High Resolution Radiometer (AVHRR, early 1990s measurements, were used to investigate the impacts of land-cover changes on natural emissions, and consequently O3 production, in the Pearl River Delta (PRD region of southern China over the past two decades. Model results indicate that BVOC emissions were highly dependent on forest area. The total BVOC emissions in the modelling domain increased by a factor of two due to afforestation since the early 1990s, declined slowly (−5.8% yr−1 until 2006 and then increased continuously (+9.1% yr−1 to 2012. The decadal variations in BVOC emissions have complex implications for summer O3 production in PRD, depending on the chemical regimes and prevailing winds. The impacts on O3 production were most sensitive in downwind areas, and it was found that the large increase in BVOC emissions during 2006–2012 tended to reduce surface O3 concentrations by 1.6–2.5 ppb in rural regions, but caused an increment of O3 peaks by up to 2.0–6.0 ppb in VOC-limited urban areas (e.g., Guangzhou, Foshan and Zhongshan. The opposite was true in the period 2001–2006, when the reduced BVOC emissions resulted in 1.3–4.0 ppb increases in daytime O3 concentrations over northern rural regions. Impact of the two-fold increase in BVOC emissions since the early 1990s to 2006 was a 0.9–4.6 ppb increment in surface O3 concentrations over the downwind areas. This study suggests that the potential impacts on ozone chemistry should be considered in long-term land-use planning and air-quality management.

  13. The Impact of Iodide-Mediated Ozone Deposition and Halogen Chemistry on Surface Ozone Concentrations Across the Continental United States

    Science.gov (United States)

    The air quality of many large coastal areas in the United States is affected by the confluence of polluted urban and relatively clean marine airmasses, each with distinct atmospheric chemistry. In this context, the role of iodide-mediated ozone (O3) deposition over seawater and m...

  14. Seasonal variation of radon concentrations in UK homes

    International Nuclear Information System (INIS)

    Miles, J C H; Howarth, C B; Hunter, N

    2012-01-01

    The patterns of seasonal variation of radon concentrations were measured in 91 homes in five regions of the UK over a period of two years. The results showed that there was no significant difference between the regions in the pattern or magnitude of seasonal variation in radon concentrations. The arithmetic mean variation was found to be close to that found previously in the UK national survey. Differences in the pattern between the two years of the study were not significant. Two-thirds of homes in the study followed the expected pattern of high radon in the winter and low radon in the summer. Most of the rest showed little seasonal variation, and a few showed a reversed seasonal pattern. The study does not provide any clear evidence for the recorded house characteristics having an effect on the seasonal variation in radon concentrations in UK homes, though the statistical power for determining such effects is limited in this study. The magnitude of the seasonal variation varied widely between homes. Analysis of the individual results from the homes showed that because of the wide variation in the amount of seasonal variation, applying seasonal correction factors to the results of three-month measurements can yield only relatively small improvements in the accuracy of estimates of annual mean concentrations.

  15. 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

  16. On the local and regional influence on ground-level ozone concentrations in Hong Kong

    International Nuclear Information System (INIS)

    So, K.L.; Wang, T.

    2003-01-01

    It is imperative to consider regional scale emissions and dynamic transport in managing ozone pollution in Hong Kong. - Hong Kong is a densely populated city situated in the fast developing Pearl River Delta of southern China. In this study, the recent data on ozone (O 3 ) and related air pollutants obtained at three sites in Hong Kong are analyzed to show the variations of O 3 in urban, sub-urban and rural areas and the possible regional influences. Highest monthly averaged O 3 was found at a northeastern rural site and lowest O 3 level was observed at an urban site. The levels of NO x , CO, SO 2 and PM 10 showed a different spatial pattern with the highest level in the urban site and lowest at the rural site. Analysis of chemical species ratios such as SO 2 /NO x and CO/NO x indicated that the sites were under the influences of local and regional emissions to varying extents reflecting the characteristics of emission sources surround the respective sites. Seasonal pattern of O 3 is examined. Low O 3 level was found in summer and elevated levels occurred in autumn and spring. The latter appears different from the previous result obtained in 1996 indicating a single maximum occurring in autumn. Principal component analysis was used to further elucidate the relationships of air pollutants at each site. As expected, the O 3 variation in the northeastern rural area was largely determined by regional chemical and transport processes, while the O 3 variability at the southwestern suburban and urban sites were more influenced by local emissions. Despite the large difference in O 3 levels across the sites, total potential ozone (O 3 +NO 2 ) showed little variability. Cases of high O 3 episodes were presented and elevated O 3 levels were formed under the influence of tropical cyclone bringing in conditions of intense sunlight, high temperature and light winds. Elevated O 3 levels were also found to correlate with enhanced ratio of SO 2 to NO x , suggesting influence of

  17. 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-07-04

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

  19. Optimization of artificial neural network models through genetic algorithms for surface ozone concentration forecasting.

    Science.gov (United States)

    Pires, J C M; Gonçalves, B; Azevedo, F G; Carneiro, A P; Rego, N; Assembleia, A J B; Lima, J F B; Silva, P A; Alves, C; Martins, F G

    2012-09-01

    This study proposes three methodologies to define artificial neural network models through genetic algorithms (GAs) to predict the next-day hourly average surface ozone (O(3)) concentrations. GAs were applied to define the activation function in hidden layer and the number of hidden neurons. Two of the methodologies define threshold models, which assume that the behaviour of the dependent variable (O(3) concentrations) changes when it enters in a different regime (two and four regimes were considered in this study). The change from one regime to another depends on a specific value (threshold value) of an explanatory variable (threshold variable), which is also defined by GAs. The predictor variables were the hourly average concentrations of carbon monoxide (CO), nitrogen oxide, nitrogen dioxide (NO(2)), and O(3) (recorded in the previous day at an urban site with traffic influence) and also meteorological data (hourly averages of temperature, solar radiation, relative humidity and wind speed). The study was performed for the period from May to August 2004. Several models were achieved and only the best model of each methodology was analysed. In threshold models, the variables selected by GAs to define the O(3) regimes were temperature, CO and NO(2) concentrations, due to their importance in O(3) chemistry in an urban atmosphere. In the prediction of O(3) concentrations, the threshold model that considers two regimes was the one that fitted the data most efficiently.

  20. Diurnal Variation of Radon Concentration in the Postojna Cave

    International Nuclear Information System (INIS)

    Gregoric, A.; Vaupotic, J.

    2011-01-01

    Postojna Cave, with 20 km of galleries, is the longest known cave system and also the largest of about 20 show caves in Slovenia and one of the most visited show caves in the world. It is well known that high concentrations of radon are common in karstic caves, although quantities of uranium (238U) in limestone are rather low. The reason for this is low natural ventilation of the underground cavities. Tectonic faults constitute an additional source of radon. Variations of radon concentration in cave air arise from a balance of the emission from cave surfaces and drip waters, decay in cave air, and exchange with the outside atmosphere. Because of its elevated radon concentrations, Postojna Cave has been under permanent radon survey since 1995. The influence of meteorological conditions on the radon levels and their temporal variations depends mostly on the shape of the cave, and the number and directions of cracks, corridors and fissures connecting the cave rooms with the outside atmosphere. The driving force for air movement in horizontal caves, and thus the inflow of fresh air and release of the cave air to the atmosphere, is the temperature difference between the cave air and outdoors, which causes seasonal pattern of radon concentration in the cave with high levels in summer and low in winter. However, on a daily scale different behaviour of radon can be observed at different locations in the cave. In this paper diurnal variation of radon concentration at two locations is presented and discussed. Postojna Cave is a horizontal cave with a stable yearly temperature around 10 degrees of @C. Continuous measurements of radon concentration were carried out from 2005 to 2010 at two locations along the guided tourist trail. Radon concentration was measured with Radim 5 WP monitors (SMM Company, Prague, Czech Republic) with sampling frequency once an hour. The evaluation of five-year radon monitoring at two sites in the Postojna Cave reveals significant diurnal and

  1. 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.

  2. 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.)

  3. 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.

  4. IASI observations of seasonal and day-to-day variations of tropospheric ozone over three highly populated areas of China: Beijing, Shanghai, and Hong Kong

    Science.gov (United States)

    Dufour, G.; Eremenko, M.; Orphal, J.; Flaud, J.-M.

    2010-04-01

    IASI observations of tropospheric ozone over the Beijing, Shanghai and Hong Kong areas during one year (2008) have been analysed, demonstrating the capability of space-borne infrared nadir measurements to probe seasonal and even day-to-day variations of lower tropospheric ozone (0-6 km partial columns) on the regional scale of highly populated areas. The monthly variations of lower tropospheric ozone retrieved from IASI clearly show the influence of the Asian summer monsoon that brings clean air masses from the Pacific during summer. They exhibit indeed a sharp ozone maximum in late spring and early summer (May-June) followed by a summer minimum. The time periods and the intensities of the maxima and of the decreases are latitude-dependent: they are more pronounced in Hong Kong and Shanghai than in Beijing. Moreover, IASI provides the opportunity to follow the spatial variations of ozone over the surroundings of each megacity as well as its daily variability. We show here that the large lower tropospheric ozone amounts (0-6 km partial columns) observed with IASI are mainly downwind the highest populated areas in each region, thus possibly suggesting the anthropogenic origin of the large ozone amounts observed. Finally, an analysis of the mean ozone profiles over each region - for selected days with high ozone events - in association with the analysis of the meteorological situation shows that the high ozone amounts observed during winter are likely related to descents of ozone-rich air from the stratosphere, whereas in spring and summer the tropospheric ozone is likely enhanced by photochemical production in polluted areas and/or in air masses from fire plumes.

  5. Interaction between local and regional pollution during Escompte 2001: impact on surface ozone concentrations (IOP2a and 2b)

    Science.gov (United States)

    Cousin, F.; Tulet, P.; Rosset, R.

    2005-03-01

    Escompte, a European programme which took place in the Marseille region in June-July 2001, has been designed as an exhaustive database to be used for the development and validation of air pollution models. The air quality Mesoscale NonHydrostatic Chemistry model (Meso-NH-C) is used to simulate 2 days of an Intensive Observation Period (IOP) documented during the Escompte campaign, June 23 and 24, 2001. We first study the synoptic and local meteorological situation on June 23 and 24, using surface and aircraft measurements. Then, we focus on the pollution episode of June 24. This study emphasizes the deep impact of synoptic and local dynamics on observed ozone concentrations. It is shown that ozone levels are due both to regional and local factors, with highlights of the importance of ozone layering. More generally this confirms, even in an otherwise predominant local sea-breeze regime, the need to consider larger scale regional pollutant transport.

  6. Seasonal variations in heavy metal concentrations in soil and some ...

    African Journals Online (AJOL)

    In this study, the seasonal variations in concentrations of the heavy metals - As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn - in soil and crops from a farm near the refuse dump site of Obafemi Awolowo University, Ile-Ife, Nigeria were investigated during the two major seasons of Nigeria. This was done to assess the pollution ...

  7. CARRY-OVER EFFECTS OF OZONE ON ROOT GROWTH AND CARBOHYDRATE CONCENTRATIONS OF PONDEROSA PINE SEEDLINGS

    Science.gov (United States)

    Ozone exposure decreases belowground carbon allocation and root growth of plants;however,the extent to which these effects persist and the cumulative impact of ozone stress on plant growth are poorly understood.To evaluate the potential for plant compensation,we followed the prog...

  8. 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)

  9. 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.

  10. 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

  11. The seasonal variation of water vapor and ozone in the upper mesosphere - Implications for vertical transport and ozone photochemistry

    Science.gov (United States)

    Bevilacqua, Richard M.; Summers, Michael E.; Strobel, Darrell F.; Olivero, John J.; Allen, Mark

    1990-01-01

    This paper reviews the data base supplied by ground-based microwave measurements of water vapor in the mesosphere obtained in three separate experiments over an eight-year period. These measurements indicate that the seasonal variation of water vapor in the mesosphere is dominated by an annual component with low values in winter and high values in summer, suggesting that the seasonal variation of water vapor in the mesosphere (below 80 km) is controlled by advective rather than diffusive processes. Both the seasonal variation and the absolute magnitude of the water vapor mixing ratios obtained in microwave measurements were corroborated by measurements obtained in the Spacelab GRILLE and ATMOS experiments, and were found to be consistent with several recent mesospheric dynamics studies.

  12. Factors affecting yearly variations of indoor radon concentrations

    International Nuclear Information System (INIS)

    Steck, D.J.; Baynes, S.A.

    1996-01-01

    Since indoor radon exposures take place over many years while radon measurement periods are shorter, we are studying the yearly variation of indoor radon concentrations in approximately 100 houses located throughout Minnesota. Most houses were initially measured for one or more years in the late 1980's and for 5 consecutive years starting in 1990. Two houses have been monitored for 12 y. Each year, two alpha track detectors were placed on the two lowest livable levels. The year-to-year variations averaged about 35% (corrected for instrumental uncertainties) in both basements and first floors. The minimum observed variation was 5% and the maximum was 130%. Some homes have shown substantial variation associated with Structural modifications. While most homes show no obvious systematic trends, a few houses have shown temporal trends that may be associated with aging or climate. We are studying possible correlation between year-to-year radon variation, climatic variables (yearly-average and seasonal such as heating/cooling degree days, precipitation, soil moisture), and structural changes

  13. Germination of fungal conidia after exposure to low concentration ozone atmospheres.

    Science.gov (United States)

    The germinability of conidia of Alternaria alternata, Aspergillus flavus, Aspergillus niger, Penicillium digitatum, Penicillium expansum, or Penicillium italicum was determined periodically during exposure for approximately 100 days to a humid atmosphere of air alone or air containing 150 ppb ozone ...

  14. 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)

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. Long-term variation of outdoor radon equilibrium equivalent concentration

    Energy Technology Data Exchange (ETDEWEB)

    Hoetzl, H. [GSF-Forschungszentrum fuer Umwelt und Gesundheit, Inst. fuer Strahlenschutz, Oberschleissheim (Germany); Winkler, R. [GSF-Forschungszentrum fuer Umwelt und Gesundheit, Inst. fuer Strahlenschutz, Oberschleissheim (Germany)

    1994-10-01

    Long-term variation of outdoor radon equilibrium equivalent concentration was investigated from 1982 to 1992 at a semi-natural location 10 km north of Munich, southern Germany. For this period the continuous measurement yielded a long-term average of 8.6 Bq.m{sup -3} (arithmetic mean) and 6.9 Bq.m{sup -3} (geometric mean), from which an average annual effective dose of 0.14 mSv due to outdoor radon can be derived. A long-term trend of the radon concentration was not detectable over the whole period of observation. However, by time series analysis, a long-term cyclic pattern was identified with two maxima (1984-1986, 1989-1991) and two minima (1982-1983, 1987-1988). The seasonal pattern is characterized by an autumn maximum and an early summer minimum. On average, the seasonal maximum in October was found to be higher by a factor of 2 than the June minimum. The diurnal variation of the radon concentration shows a maximum in the early morning and a minimum in the afternoon. On average, this maximum is a factor of 2 higher than the minimum. In the long term a seasonal pattern was observed for diurnal variation, with an average diurnal maximum to minimum ratio of 1.5 in winter compared with 3.5 in the summer months. The radon concentration is correlated with a meteorological parameter (stagnation index) which takes into account horizontal and vertical exchange processes and the wash-out of aerosols in the lower atmosphere. (orig.)

  20. Long-term variation of outdoor radon equilibrium equivalent concentration

    International Nuclear Information System (INIS)

    Hoetzl, H.; Winkler, R.

    1994-01-01

    Long-term variation of outdoor radon equilibrium equivalent concentration was investigated from 1982 to 1992 at a semi-natural location 10 km north of Munich, southern Germany. For this period the continuous measurement yielded a long-term average of 8.6 Bq.m -3 (arithmetic mean) and 6.9 Bq.m -3 (geometric mean), from which an average annual effective dose of 0.14 mSv due to outdoor radon can be derived. A long-term trend of the radon concentration was not detectable over the whole period of observation. However, by time series analysis, a long-term cyclic pattern was identified with two maxima (1984-1986, 1989-1991) and two minima (1982-1983, 1987-1988). The seasonal pattern is characterized by an autumn maximum and an early summer minimum. On average, the seasonal maximum in October was found to be higher by a factor of 2 than the June minimum. The diurnal variation of the radon concentration shows a maximum in the early morning and a minimum in the afternoon. On average, this maximum is a factor of 2 higher than the minimum. In the long term a seasonal pattern was observed for diurnal variation, with an average diurnal maximum to minimum ratio of 1.5 in winter compared with 3.5 in the summer months. The radon concentration is correlated with a meteorological parameter (stagnation index) which takes into account horizontal and vertical exchange processes and the wash-out of aerosols in the lower atmosphere. (orig.)

  1. 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

  2. Variation among chlorine concentration ratios for native and agronomic plants

    International Nuclear Information System (INIS)

    Sheppard, S.C.; Evenden, W.G.; Macdonald, C.R.

    1999-01-01

    Variation among plant/soil concentration ratios (CRs) for important radionuclides requires attention because it is a major source of uncertainty in nuclear environmental safety assessments. For agronomic plants, variation among plant species is easy to deal with because there are relatively few species. In natural settings, there are vastly more species and the question becomes how to develop representative statistical distributions of CRs. Chlorine (Cl) is a good element with which to address this problem, because 36 Cl is a key radionuclide in nuclear waste disposal and yet stable Cl is easily measured in the environment. We measured CRs (dry weight basis) for Cl among edible parts of agronomic plants at one site, and found a geometric mean (GM) of 10, a geometric standard deviation (GSD) of 1.9 and a range of 5-66. When the GM was weighted by the relative contributions of the various plants to the human diet, it rose to 16. Among native plants at five sites, each site representative of a specific environment, the GMs were 4.0-13 and the GSDs were 2.9-6.2. The CRs for individual species ranged from 0.8 to 170. However, when weighted by relative contributions of the plants to selected animal diets, the GMs were as high as 50. The conclusions are that: the variation in CR for agronomic plants is a subset of the variation among native or all plants, variation among species (the GSD) can be sixfold, and variation among species is large enough that typical diets of specific animals could expose them to several-fold higher amounts of Cl (or 36 Cl) than expected from generic CR values. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  3. Seasonal differences and within-canopy variations of antioxidants in mature spruce (Picea abies) trees under elevated ozone in a free-air exposure system

    International Nuclear Information System (INIS)

    Hofer, Nora; Alexou, Maria; Heerdt, Christian; Loew, Markus; Werner, Herbert; Matyssek, Rainer; Rennenberg, Heinz; Haberer, Kristine

    2008-01-01

    The effect of free-air ozone fumigation and crown position on antioxidants were determined in old-growth spruce (Picea abies) trees in the seasonal course of two consecutive years (2003 and 2004). Levels of total ascorbate and its redox state in the apoplastic washing fluid (AWF) were increased under double ambient ozone concentrations (2 x O 3 ), whilst ascorbate concentrations in needle extracts were unchanged. Concentrations of apoplastic and symplastic ascorbate were significantly higher in 2003 compared to 2004 indicating a combined effect of the drought conditions in 2003 with enhanced ozone exposure. Elevated ozone had only weak effects on total glutathione levels in needle extracts, phloem exudates and xylem saps. Total and oxidised glutathione concentrations were higher in 2004 compared to 2003 and seemed to be more affected by enhanced ozone influx in the more humid year 2004 compared to the combined effect of elevated ozone and drought in 2003 as observed for ascorbate. - Antioxidant defence in sun and shade needles of Picea abies under free-air ozone fumigation in the seasonal course of two consecutive years

  4. Global tropospheric ozone variations from 2003 to 2011 as seen by SCIAMACHY

    Directory of Open Access Journals (Sweden)

    F. Ebojie

    2016-01-01

    Full Text Available An analysis of the tropospheric ozone (O3 columns (TOCs derived from SCIAMACHY limb-nadir-matching (LNM observations during the period 2003–2011, focusing on global variations in TOC, is described. The changes are derived using a multivariate linear regression model. TOC shows changes of −0.2 ± 0.4, 0.3 ± 0.4, 0.1 ± 0.5 and 0.1 ± 0.2 % yr−1, which are not statistically significant at the 2σ level in the latitude bands 30–50° N, 20° S–0, 0–20° N and 50–30° S, respectively. Tropospheric O3 shows statistically significant increases over some regions of South Asia (1–3 % yr−1, the South American continent (up to 2 % yr−1, Alaska (up to 2 % yr−1 and around Congo in Africa (up to 2 % yr−1. Significant increase in TOC is determined off the continents including Australia (up to 2 % yr−1, Eurasia (1–3 % yr−1 and South America (up to 3 % yr−1. Significant decrease in TOC (up to −3 % yr−1 is observed over some regions of the continents of North America, Europe and South America. Over the oceanic regions including the Pacific, North Atlantic and Indian oceans, significant decreases in TOC (−1 to −3 % yr−1 were observed. In addition, the response of the El Niño–Southern Oscillation (ENSO and quasi-biennial oscillation (QBO to changes in TOC for the period 2003–2011 was investigated. The result shows extensive regions, mostly in the tropics and Northern Hemisphere extratropics, of significant ENSO responses to changes in TOC and a significant QBO response to TOC changes over some regions.

  5. 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.

  6. 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

  7. Principal component analysis and neurocomputing-based models for total ozone concentration over different urban regions of India

    Science.gov (United States)

    Chattopadhyay, Goutami; Chattopadhyay, Surajit; Chakraborthy, Parthasarathi

    2012-07-01

    The present study deals with daily total ozone concentration time series over four metro cities of India namely Kolkata, Mumbai, Chennai, and New Delhi in the multivariate environment. Using the Kaiser-Meyer-Olkin measure, it is established that the data set under consideration are suitable for principal component analysis. Subsequently, by introducing rotated component matrix for the principal components, the predictors suitable for generating artificial neural network (ANN) for daily total ozone prediction are identified. The multicollinearity is removed in this way. Models of ANN in the form of multilayer perceptron trained through backpropagation learning are generated for all of the study zones, and the model outcomes are assessed statistically. Measuring various statistics like Pearson correlation coefficients, Willmott's indices, percentage errors of prediction, and mean absolute errors, it is observed that for Mumbai and Kolkata the proposed ANN model generates very good predictions. The results are supported by the linearly distributed coordinates in the scatterplots.

  8. Observations of reduced ozone concentrations in the tropical stratosphere after the eruption of Mt. Pinatubo

    Science.gov (United States)

    Grant, W. B.; Fishman, J.; Browell, E. V.; Brackett, V. G.; Nganga, D.; Minga, A.; Cros, B.; Veiga, R. E.; Butler, C. F.; Fenn, M. A.

    1992-01-01

    Two independent sets of data, one of aerosols from an airborne lidar system, and one of ozone from ozonesonde measurements indicate that significant ozone decreases may have happened as a result of the injection of debris by the Mt. Pinatubo volcano in June 1991. The amount of this reduction maximizes at 24-25 km, near the peak of the aerosol distribution, though a deficit is seen throughout the lower stratosphere between 19 and 28 km. The greatest differences observed prior and subsequent to the eruptions at these altitudes is 18-20 percent.

  9. Measuring the concentration of ozone produced by a pulsed microwave discharge

    Science.gov (United States)

    Stepanov, A. N.; Iazenkov, V. V.

    1991-09-01

    The possibility of efficient ozone production in a pulsed microwave discharge in oxygen is investigated experimentally in the context of the problem of creation of an artificial ionization region in the earth atmosphere. The experiments were conducted in commercial oxygen at a pressure of 30 tor. It is found that there exists a certain optimal (from the standpoint of ozone production) microwave pulse duration, which depends on the experimental conditions. A theoretical model is proposed which provides a consistent explanation for the experimental results.

  10. 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.

  11. Variation in caffeine concentration in single coffee beans.

    Science.gov (United States)

    Fox, Glen P; Wu, Alex; Yiran, Liang; Force, Lesleigh

    2013-11-13

    Twenty-eight coffee samples from around the world were tested for caffeine levels to develop near-infrared reflectance spectroscopy (NIRS) calibrations for whole and ground coffee. Twenty-five individual beans from five of those coffees were used to develop a NIRS calibration for caffeine concentration in single beans. An international standard high-performance liquid chromatography method was used to analyze for caffeine content. Coffee is a legal stimulant and possesses a number of heath properties. However, there is variation in the level of caffeine in brewed coffee and other caffeinated beverages. Being able to sort beans on the basis of caffeine concentration will improve quality control in the level of caffeine in those beverages. The range in caffeine concentration was from 0.01 mg/g (decaffeinated coffee) to 19.9 mg/g (Italian coffee). The majority of coffees were around 10.0-12.0 mg/g. The NIRS results showed r(2) values for bulk unground and ground coffees were >0.90 with standard errors coffee beans. One application of this calibration could be sorting beans on caffeine concentration to provide greater quality control for high-end markets. Furthermore, bean sorting may open new markets for novel coffee products.

  12. Influence of ozone precursors and particulate matter on the variation of surface ozone at an urban site of Delhi, India

    Directory of Open Access Journals (Sweden)

    Ashima Sharma

    2016-03-01

    Full Text Available Continuous measurements of surface O3 and its precursors (NO, NO2, CO, CH4 and NMHCs at an urban site of Delhi, India during January 2012 to December 2013 are presented. In the present study, the annual average mixing ratios of surface O3, NO, NO2, CO, CH4 and NMHC were 30 ± 6 ppb, 24 ± 6 ppb, 15 ± 4 ppb, 1.5 ± 0.4 ppm, 2.4 ± 0.4 ppm and 0.4 ± 0.1 ppm, respectively. The maximum average mixing ratios of surface O3, NO and NO2 were observed during the summer, whereas, the minimum average mixing ratios of ambient NO and NO2 were during monsoon seasons. The surface O3, NO and NO2 have shown the prominent diurnal variations during all the seasons at the observational site of Delhi. The result reveals that the surface O3 was negatively correlated with NOx and CO during the study. The linear scatter plot analysis shows that the PM2.5 and PM10 present in the ambient air of Delhi influence the production of surface O3 at observational site.

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

    NARCIS (Netherlands)

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

    2016-01-01

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

  14. Climate Change Impacts on Human Health Due to Changes in Ambient Ozone Concentrations (External Review Draft)

    Science.gov (United States)

    This report uses results from a previous report titled Assessment of the Impacts of Global Change on Regional U.S. Air Quality: A Synthesis of Climate Change Impacts on Ground-Level Ozone, a number of high-resolution, spatially explicit population projections developed ...

  15. 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

  16. 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

  17. Impacts of a large boreal wildfire on ground level atmospheric concentrations of PAHs, VOCs and ozone

    Science.gov (United States)

    Wentworth, Gregory R.; Aklilu, Yayne-abeba; Landis, Matthew S.; Hsu, Yu-Mei

    2018-04-01

    During May 2016 a very large boreal wildfire burned throughout the Athabasca Oil Sands Region (AOSR) in central Canada, and in close proximity to an extensive air quality monitoring network. This study examines speciated 24-h integrated polycyclic aromatic hydrocarbon (PAH) and volatile organic compound (VOC) measurements collected every sixth day at four and seven sites, respectively, from May to August 2016. The sum of PAHs (ΣPAH) was on average 17 times higher in fire-influenced samples (852 ng m-3, n = 8), relative to non-fire influenced samples (50 ng m-3, n = 64). Diagnostic PAH ratios in fire-influenced samples were indicative of a biomass burning source, whereas ratios in June to August samples showed additional influence from petrogenic and fossil fuel combustion. The average increase in the sum of VOCs (ΣVOC) was minor by comparison: 63 ppbv for fire-influenced samples (n = 16) versus 46 ppbv for non-fire samples (n = 90). The samples collected on August 16th and 22nd had large ΣVOC concentrations at all sites (average of 123 ppbv) that were unrelated to wildfire emissions, and composed primarily of acetaldehyde and methanol suggesting a photochemically aged air mass. Normalized excess enhancement ratios (ERs) were calculated for 20 VOCs and 23 PAHs for three fire influenced samples, and the former were generally consistent with previous observations. To our knowledge, this is the first study to report ER measurements for a number of VOCs and PAHs in fresh North American boreal wildfire plumes. During May the aged wildfire plume intercepted the cities of Edmonton (∼380 km south) or Lethbridge (∼790 km south) on four separate occasions. No enhancement in ground-level ozone (O3) was observed in these aged plumes despite an assumed increase in O3 precursors. In the AOSR, the only daily-averaged VOCs which approached or exceeded the hourly Alberta Ambient Air Quality Objectives (AAAQOs) were benzene (during the fire) and acetaldehyde (on August 16th

  18. 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.

  19. 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.

  20. Differential Absorption Lidar to Measure Subhourly Variation of Tropospheric Ozone Profiles

    Science.gov (United States)

    Kuang, Shi; Burris, John F.; Newchurch, Michael J.; Johnson, Steve; Long, Stephania

    2011-01-01

    A tropospheric ozone Differential Absorption Lidar system, developed jointly by The University of Alabama in Huntsville and the National Aeronautics and Space Administration, is making regular observations of ozone vertical distributions between 1 and 8 km with two receivers under both daytime and nighttime conditions using lasers at 285 and 291 nm. This paper describes the lidar system and analysis technique with some measurement examples. An iterative aerosol correction procedure reduces the retrieval error arising from differential aerosol backscatter in the lower troposphere. Lidar observations with coincident ozonesonde flights demonstrate that the retrieval accuracy ranges from better than 10% below 4 km to better than 20% below 8 km with 750-m vertical resolution and 10-min 17 temporal integration.

  1. Assessment of atmospheric processes driving ozone variations in the subtropical North Atlantic free troposphere

    Directory of Open Access Journals (Sweden)

    E. Cuevas

    2013-02-01

    Full Text Available An analysis of the 22-yr ozone (O3 series (1988–2009 at the subtropical high mountain Izaña~station (IZO; 2373 m a.s.l., representative of free troposphere (FT conditions, is presented. Diurnal and seasonal O3 variations as well as the O3 trend (0.19 ± 0.05 % yr−1 or 0.09 ppbv yr−1, are assessed. A climatology of O3 transport pathways using backward trajectories shows that higher O3 values are associated with air masses travelling above 4 km altitude from North America and North Atlantic Ocean, while low O3 is transported from the Saharan continental boundary layer (CBL. O3 data have been compared with PM10, 210Pb, 7Be, potential vorticity (PV and carbon monoxide (CO. A clear negative logarithmic relationship was observed between PM10 and surface O3 for all seasons. A similar relationship was found between O3 and 210Pb. The highest daily O3 values (90th percentile are observed in spring and in the first half of summer time. A positive correlation between O3 and PV, and between O3 and 7Be is found throughout the year, indicating that relatively high surface O3 values at IZO originate from the middle and upper troposphere. We find a good correlation between O3 and CO in winter, supporting the hypothesis of long-range transport of photochemically generated O3 from North America. Aged air masses, in combination with sporadic inputs from the upper troposphere, are observed in spring, summer and autumn. In summer time high O3 values seem to be the result of stratosphere-to-troposphere (STT exchange processes in regions neighbouring the Canary Islands. Since 1995–1996, the North Atlantic Oscillation has changed from a predominantly high positive phase to alternating between negative

  2. Breeding of ozone resistant rice: Relevance, approaches and challenges

    International Nuclear Information System (INIS)

    Frei, Michael

    2015-01-01

    Tropospheric ozone concentrations have been rising across Asia, and will continue to rise during the 21st century. Ozone affects rice yields through reductions in spikelet number, spikelet fertility, and grain size. Moreover, ozone leads to changes in rice grain and straw quality. Therefore the breeding of ozone tolerant rice varieties is warranted. The mapping of quantitative trait loci (QTL) using bi-parental populations identified several tolerance QTL mitigating symptom formation, grain yield losses, or the degradation of straw quality. A genome-wide association study (GWAS) demonstrated substantial natural genotypic variation in ozone tolerance in rice, and revealed that the genetic architecture of ozone tolerance in rice is dominated by multiple medium and small effect loci. Transgenic approaches targeting tolerance mechanisms such as antioxidant capacity are also discussed. It is concluded that the breeding of ozone tolerant rice can contribute substantially to the global food security, and is feasible using different breeding approaches. - Highlights: • Tropospheric ozone affects millions of hectares of rice land. • Ozone affects rice yield and quality. • Breeding approaches to adapt rice to high ozone are discussed. • Challenges in the breeding of ozone resistant rice are discussed. - This review summarizes the effects of tropospheric ozone on rice and outlines approaches and challenges in the breeding of adapted varieties

  3. Concentrations of motor vehicle exhaust emissions and ozone in the area surrounding a motorway; Konzentrationen von Kraftfahrzeugemissionen und Ozon im Nahbereich einer Autobahn

    Energy Technology Data Exchange (ETDEWEB)

    Corsmeier, U.; Vogel, H. [Forschungszentrum Karlsruhe GmbH Umwelt und Technik (Germany). Inst. fuer Meteorologie und Klimaforschung]|[Karlsruhe Univ. (T.H.). (Germany). Inst. fuer Meteorologie und Klimaforschung

    1998-01-01

    The measuring concept realized along the federal motorway BAB656, which makes use of meteorological and air-chemical measuring techniques under selected meteorological conditions, permits detecting the plume of motorway exhaust emissions beyond doubt. By simultaneous, comprehensive traffic surveys, the input parameters for numerical emission calculation models valid up to now could be verified. In part, as regards trafic density, fleet composition and driving speed, they were corrected. From the difference between the vertical profiles of the meteorological parameters and ozone concentration measured at the luff and lee sides of the motorway and from measurements of the concentrations of primarily emitted substances at ground level, the actual emissions of these substances for the motorway segment in kgh{sup 1} km{sup -}1 were calculated. (orig./KW) [Deutsch] Es konnte gezeigt werden, dass mit dem bei BAB656 realisierten Messkonzept mit Hilfe meteorologischer und luftchemischer Messtechnik bei ausgesuchten meteorologischen Bedingungen die Abluftfahne mit den auf einer Autobahn emittierten Substanzen zweifelsfrei detektiert werden kann. Durch gleichzeitige umfangreiche Verkehrserhebungen konnten die bisher gueltigen Eingabeparameter fuer numerische Emissionsberechnungsmodelle ueberprueft und was Verkehrsdichte, Flottenzusammensetzung und Fahrgeschwindigkeit angeht, teilweise korrigiert werden. Aus der Differenz der im Luv und Lee der Autobahn gemessenen Vertikalprofile meteorologischer Parameter und der Ozonkonzentration sowie der Messung der Konzentrationen primaer emittierter Substanzen am Boden konnten die Emissionen dieser Stoffe fuer den Autobahnabschnitt in kgh{sup -1} km{sup -1} aktuell berechnet werden. (orig./KW)

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

    Science.gov (United States)

    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

  5. 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

  6. Ozone and Water Stress: Effects on the Behaviour of Two White Clover Biotypes

    Directory of Open Access Journals (Sweden)

    Massimo Fagnano

    Full Text Available ozone pollution, water stress, stomata conductance, ozone uptake, clover, OTC.Ozone is a strong oxidizing pollutant which derives by alteration of the photolytic NOx cycle and it accumulates in the troposphere spreading in rural areas and therefore determining injuries on natural vegetation and crops. Since its penetration occurs mainly through stomata, all factors which alter plant-atmosphere relations could be able to modify plant response to ozone. Interaction between ozone and water stress in Mediterranean environment was studied on ozone resistant and sensitive biotypes of white clover, which were grown in charcoal filtered and notfiltered Open Top Chambers in factorial combination with different levels of water supply. Measurements of biomass, leaf area and stomatal conductance were made during the growth period. Ozone injuries were estimated as not-filtered/filtered OTC yield ratio; the stomatal flux of ozone was estimated multiplying stomata conductance x diffusivity ratio between ozone and water vapour (0.613 x ozone hourly concentrations. The hourly values of ozone uptake were cumulated throughout the cropping periods of the two years. In the sensitive biotype, water stress reduced yield losses due to ozone from 38% to 22%, as well as yield losses due to water stress were reduced by the presence of ozone from 43% to 29%, while no interaction between ozone and water stress was observed in the resistant biotype. Biomass yield losses of the sensitive biotype were strictly correlated to cumulated ozone uptake (R2 = 0.99, while biomass yield losses of the resistant biotype were not affected by the ozone fluxes variations created by the treatments. Flux based models could better estimate yield losses due to ozone in Mediterranean environments in which other stresses could be contemporary present; therefore, the new European directives might replace the actual thresholds based

  7. 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

  8. 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.

  9. 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

  10. 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.

  11. Spatiotemporal Variation in Mangrove Chlorophyll Concentration Using Landsat 8

    Directory of Open Access Journals (Sweden)

    Julio Pastor-Guzman

    2015-11-01

    Full Text Available There is a need to develop indicators of mangrove condition using remotely sensed data. However, remote estimation of leaf and canopy biochemical properties and vegetation condition remains challenging. In this paper, we (i tested the performance of selected hyperspectral and broad band indices to predict chlorophyll concentration (CC on mangrove leaves and (ii showed the potential of Landsat 8 for estimation of mangrove CC at the landscape level. Relative leaf CC and leaf spectral response were measured at 12 Elementary Sampling Units (ESU distributed along the northwest coast of the Yucatan Peninsula, Mexico. Linear regression models and coefficients of determination were computed to measure the association between CC and spectral response. At leaf level, the narrow band indices with the largest correlation with CC were Vogelmann indices and the MTCI (R2 > 0.5. Indices with spectral bands around the red edge (705–753 nm were more sensitive to mangrove leaf CC. At the ESU level Landsat 8 NDVI green, which uses the green band in its formulation explained most of the variation in CC (R2 > 0.8. Accuracy assessment between estimated CC and observed CC using the leave-one-out cross-validation (LOOCV method yielded a root mean squared error (RMSE = 15 mg·cm−2, and R2 = 0.703. CC maps showing the spatiotemporal variation of CC at landscape scale were created using the linear model. Our results indicate that Landsat 8 NDVI green can be employed to estimate CC in large mangrove areas where ground networks cannot be applied, and mapping techniques based on satellite data, are necessary. Furthermore, using upcoming technologies that will include two bands around the red edge such as Sentinel 2 will improve mangrove monitoring at higher spatial and temporal resolutions.

  12. Simulation of the interannual variations of biogenic emissions of volatile organic compounds in China: Impacts on tropospheric ozone and secondary organic aerosol

    Science.gov (United States)

    Fu, Y.; Liao, H.

    2012-12-01

    We use the MEGAN (Model of emissions of Gases and Aerosols from Nature) module embedded within the global three-dimensional Goddard Earth Observing System chemical transport model (GEOS-Chem) to simulate the interannual variations in biogenic volatile organic compound (BVOC) emissions and concentrations of ozone and secondary organic aerosols (SOA) in China over years 2001-2006. To have better representation of biogenic emissions, we have updated in the model the land cover and leaf area index in China using Moderate Resolution Imaging Spectroradiometer (MODIS) satellite measurements, and we have developed a new classification of vegetation with 21 plant functional types. Estimated annual BVOC emission in China averaged over 2001-2006 is 18.85 Tg C yr-1, in which emissions of isoprene, monoterpenes, and other reactive volatile organic compounds account for 50.9%, 15.0%, and 34.1%, respectively. The simulated BVOC emissions in China have large interannual variations. The values of regionally averaged absolute percent departure from the mean (APDM) of isoprene emissions are in the range of 21-42% in January and 15-28% in July. The APDM values of monoterpene emissions are 14-32% in January and 10-21% in July, which are generally smaller than those of isoprene emissions. Model results indicate that the interannual variations in isoprene emissions are more dependent on variations in meteorological fields, whereas the interannual variations in monoterpene emissions are more sensitive to changes in vegetation parameters. With fixed anthropogenic emissions, as a result of the variations in both meteorological parameters and vegetation, simulated O3 concentrations show interannual variations of 0.8-5 ppbv (or largest APDM values of 4-15%), and simulated SOA shows APDM values of 5-15% in southwestern China in January as well as 10-25% in southeastern and 20-35% in northeastern China in July. On a regional mean basis, the interannual variations in BVOCs alone can lead to 2

  13. Understanding Long-Term Variations in Surface Ozone in United States (U.S. National Parks

    Directory of Open Access Journals (Sweden)

    Deborah McGlynn

    2018-03-01

    Full Text Available Long-term surface ozone observations at 25 National Park Service sites across the United States were analyzed for processes on varying time scales using a time scale decomposition technique, the Ensemble Empirical Mode Decomposition (EEMD. Time scales of interest include the seasonal cycle, large-scale climate oscillations, and long-term (>10 years trends. Emission reductions were found to have a greater impact on sites that are nearest major urban areas. Multidecadal trends in surface ozone were increasing at a rate of 0.07 to 0.37 ppbv year−1 before 2004 and decreasing at a rate of −0.08 to −0.60 ppbv year−1 after 2004 for sites in the East, Southern California, and Northwestern Washington. Sites in the Intermountain West did not experience a reversal of trends from positive to negative until the mid- to late 2000s. The magnitude of the annual amplitude (=annual maximum–minimum decreased at eight sites, two in the West, two in the Intermountain West, and four in the East, by 5–20 ppbv and significantly increased at three sites; one in Alaska, one in the West, and one in the Intermountain West, by 3–4 ppbv. Stronger decreases in the annual amplitude occurred at a greater proportion of sites in the East (4/6 sites than in the West/Intermountain West (4/19 sites. The date of annual maximums and/or minimums has changed at 12 sites, occurring 10–60 days earlier in the year. There appeared to be a link between the timing of the annual maximum and the decrease in the annual amplitude, which was hypothesized to be related to a decrease in ozone titration resulting from NOx emission reductions. Furthermore, it was found that a phase shift of the Pacific Decadal Oscillation (PDO, from positive to negative, in 1998–1999 resulted in increased occurrences of La Niña-like conditions. This shift had the effect of directing more polluted air masses from East Asia to higher latitudes over the North American continent. The change in the

  14. Climatology of UVA and ozone variations and the global solar UV-index

    International Nuclear Information System (INIS)

    Roy, C.R.; Gies, H.P.; Toomey, S.J.

    1996-01-01

    Human overexposure to solar ultraviolet radiation (UVR) can result in acute and chronic adverse health effects on both the skin and the eye. Skin cancer (both non-melanoma and malignant melanoma) and cataract impose a huge social and cost burden on many societies throughout the world. Such human health problems can be avoided if the individual reduces their UVR exposure. Unfortunately enlightenment may not help persons who have experienced high episodic exposures during childhood as this appears to be an important causal factor in melanoma. In some countries public educational campaigns have been underway for decades in other countries they are just beginning; the global solar uv-index provides a globally consistent means of reporting or predicting UVR as part of public education on UVR exposure. There are now indications that some of these programs have been effective in halting the climb in melanoma incidence. The UVR, and in particular UVB, reaching the earth's surface varies with both latitude and time (both of the day and year). The transmission of the extraterrestrial radiation through the atmosphere is determined by ozone clouds, aerosols and to a lesser extent, trace gases. In recent decades there has been considerable concern that long-term changes in ozone and perhaps clouds and aerosols may result in changes in the UVB at the earth's surface. (author)

  15. 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%.

  16. Temporal Variation in Air Pollution Concentrations and Preterm Birth—A Population Based Epidemiological Study

    Directory of Open Access Journals (Sweden)

    Bertil Forsberg

    2012-01-01

    Full Text Available There is growing evidence of adverse birth outcomes due to exposure to air pollution during gestation. However, recent negative studies are also reported. The aim of this study was to assess the effect of ozone and vehicle exhaust exposure (NO2 on the length of the gestational period and risk of preterm delivery. We used data from the Swedish Medical Birth Registry on all vaginally delivered singleton births in the Greater Stockholm area who were conceived during 1987–1995 (n = 115,588. Daily average levels of NO2 (from three measuring stations and ozone (two stations were used to estimate trimester and last week of gestation average exposures. Linear regression models were used to assess the association between the two air pollutants and three exposure windows, while logistic regression models were used when analyzing associations with preterm delivery ( < 37 weeks gestation. Five percent were born preterm. The median gestational period was 40 weeks. Higher levels of ozone during the first trimester were associated with shorter gestation as well as with an elevated risk of preterm delivery, the odds ratio from the most complex model was 1.06 (95% CI: 1.00–1.13 per 10 μg/m3 increase in the mean daily 8-h maximum concentration. Higher levels of ozone during the second trimester were associated with shorter gestation but the elevated risk of preterm delivery was not statistically significant. Higher levels of ozone and NO2 during the last week of gestation were associated with a shorter duration of gestation and NO2 also with preterm delivery. There were no significant associations between first and second trimester NO2 exposure estimates and studied outcomes. The effect of first trimester ozone exposure, known to cause oxidative stress, was smallest among women who conceived during autumn when vitamin D status, important for fetal health, in Scandinavian women is the highest.

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

    Science.gov (United States)

    Background: Associations between ozone (O3) and fine particulate matter (PM2.5) concentrations and birth outcomes have been previously demonstrated. We perform an exploratory analysis of O3 and PM2.5 concentrations during early pregnancy and multiple types of birth defects. Met...

  18. 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.

  19. Combined cadmium and elevated ozone affect concentrations of cadmium and antioxidant systems in wheat under fully open-air conditions

    International Nuclear Information System (INIS)

    Guo, Hongyan; Tian, Ran; Zhu, Jianguo; Zhou, Hui; Pei, Daping; Wang, Xiaorong

    2012-01-01

    Highlights: ► Combined effect of elevated O 3 and Cd levels on wheat was studied using the free-air concentration enrichment system. ► Elevated O 3 levels result in an increased concentration of Cd in wheat plants grown on Cd-contaminated soils. ► Combined cadmium and elevated O 3 have a significantly synergic effect on oxidative stress in wheat shoots. - Abstract: Pollution of the environment with both ozone (O 3 ) and heavy metals has been steadily increasing. An understanding of their combined effects on plants, especially crops, is limited. Here we studied the effects of elevated O 3 on oxidative stress and bioaccumulation of cadmium (Cd) in wheat under Cd stress using a free-air concentration enrichment (FACE) system. In this field experiment in Jiangdu (Jiangsu Province, China), wheat plants were grown in pots containing soil with various concentrations of cadmium (0, 2, and 10 mg kg −1 Cd was added to the soil) under ambient conditions and under elevated O 3 levels (50% higher than the ambient O 3 ). Present results showed that elevated O 3 led to higher concentrations of Cd in wheat tissues (shoots, husk and grains) with respect to contaminated soil. Combined exposure to Cd and elevated O 3 levels strongly affected the antioxidant isoenzymes POD, APX and CAT and accelerated oxidative stress in wheat leaves. Our results suggest that elevated O 3 levels cause a reduction in food quality and safety.

  20. Variation of atmospheric 210Pb concentration in the inland area of Chinese continent

    International Nuclear Information System (INIS)

    Doi, Taeko; Sato, Jun.

    1995-01-01

    Atmospheric concentrations of 210 Pb and their variations over Urumqi, Lanzhou and Baotou, cities located in inland area of Chinese continent, were observed for a period of 1 year in 1992. The monthly average concentrations ranged from 0.27 to 4.57 mBq/m 3 . The concentrations over these cities in winter were several times higher than that observed at Tsukuba Science City, Japan, and the range of variation was also larger. The variations in concentration over the 3 localities were similar to each other, showing the same seasonal variation pattern: low concentration appeared in summer and high in winter. This variation pattern was different from that observed at Tsukuba Science City. The variations in concentration over Chinese continent, where precipitation is much lower than that in Japan, correlated quite well with the variation in precipitation. (author)

  1. Seasonal and daily variation in blood and urine concentrations of ...

    African Journals Online (AJOL)

    1998-03-17

    Mar 17, 1998 ... ... both seasonal and daily cyclic variation in water stress, with concomitant changes in ... nutritional) stress, are of dubious applicability to animals in their natural ..... The similarity of haematocrit measurements in the two sea-.

  2. Spatial variation in nitrogen dioxide concentrations and cardiopulmonary hospital admissions

    NARCIS (Netherlands)

    Dijkema, Marieke B A; van Strien, Robert T; van der Zee, Saskia C; Mallant, Sanne F; Fischer, Paul; Hoek, Gerard; Brunekreef, Bert; Gehring, Ulrike

    2016-01-01

    BACKGROUND: Air pollution episodes are associated with increased cardiopulmonary hospital admissions. Cohort studies showed associations of spatial variation in traffic-related air pollution with respiratory and cardiovascular mortality. Much less is known in particular about associations with

  3. The impact of the observation nudging and nesting on the simulated meteorology and ozone concentrations from WRF-SMOKE-CMAQ during DISCOVER-AQ 2013 Texas campaign

    Science.gov (United States)

    Choi, Y.; Li, X.; Czader, B.

    2014-12-01

    Three WRF simulations for the DISCOVER-AQ 2013 Texas campaign period (30 days in September) are performed to characterize uncertainties in the simulated meteorological and chemical conditions. These simulations differ in domain setup, and in performing observation nudging in WRF runs. There are around 7% index of agreement (IOA) gain in temperature and 9-12% boost in U-WIND and V-WIND when the observational nudging is employed in the simulation. Further performance gain from nested domains over single domain is marginal. The CMAQ simulations based on above WRF setups showed that the ozone performance slightly improved in the simulation for which objective analysis (OA) is carried out. Further IOA gain, though quite limited, is achieved with nested domains. This study shows that the high ozone episodes during the analyzed time periods were associated with the uncertainties of the simulated cold front passage, chemical boundary condition and small-scale temporal wind fields. All runs missed the observed high ozone values which reached above 150 ppb in La Porte on September 25, the only day with hourly ozone over 120 ppb. The failure is likely due to model's inability to catch small-scale wind shifts in the industrial zone, despite better wind directions in the simulations with nudging and nested domains. This study also shows that overestimated background ozone from the southerly chemical boundary is a critical source for the model's general overpredictions of the ozone concentrations from CMAQ during September of 2013. These results of this study shed a light on the necessity of (1) capturing the small-scale winds such as the onsets of bay-breeze or sea-breeze and (2) implementing more accurate chemical boundary conditions to reduce the simulated high-biased ozone concentrations. One promising remedy for (1) is implementing hourly observation nudging instead of the standard one which is done every three hours.

  4. 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.

  5. 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

  6. Interannual variations in the zonal asymmetry of the subpolar latitudes total ozone column during the austral spring

    Directory of Open Access Journals (Sweden)

    Eduardo A. Agosta

    2010-06-01

    Full Text Available The Southern Hemisphere midlatitude Total Ozone Column (TOC shows a horseshoe like structure with a minimum which appears to have two preferential extreme positions during October: one, near southern South America, the other, near the Greenwich Meridian approximately. The interannual zonal ozone asymmetry exists independently of the variations induced by the 11-year solar cycle, the Quasi-Biennial Oscillation (QBO and planetary wave activity inducing the Brewer-Dobson circulation. The classification and climatological composition of these two extreme ozone-minimum positions allows for the observations of statistically significant patterns in geopotential height and zonal winds associated with the quasi-stationary wave 1, extending throughout lower stratosphere. The changes in the quasi-stationary wave 1 associated with the extreme TOC positions appear to have sinks and sources determining transient interactions between troposphere and the stratosphere. Thus, distinct climate states in the troposphere seem to be dynamically linked with the state of the stratosphere and ozone layer. The migration of the TOC trough from southern South America to the east during the 1990s can be related to changes in the troposphere/stratosphere coupling through changes in the Southern Annular Mode variability in spring.La Columna Total de Ozono (CTO de las latitudes medias del Hemisferio Sur muestra una estructura de herradura con un mínimo que muestra tener dos posiciones preferenciales extremas durante octubre: uno, en las cercanías del sur de Sudamérica, y el otro, cerca del meridiano de Greenwich. La asimetría zonal de ozono existe independientemente de las variaciones inducidas por el ciclo solar de 11 años, la Oscilación Cuasi-Bianual (QBO y la actividad de onda planetaria asociada a la circulación de Brewer-Dobson. La clasificación y composición climatológica de estas dos situaciones longitudinalmente extremas de mínimo de ozono permite observar

  7. 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

  8. 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.

  9. Spatial and temporal variations of manganese concentrations in drinking water.

    Science.gov (United States)

    Barbeau, Benoit; Carrière, Annie; Bouchard, Maryse F

    2011-01-01

    The objective of this study was to assess the variability of manganese concentrations in drinking water (daily, seasonal, spatial) for eight communities who participated in an epidemiological study on neurotoxic effects associated with exposure to manganese in drinking water. We also assessed the performance of residential point-of-use and point-of-entry devices (POE) for reducing manganese concentrations in water. While the total Mn concentrations measured during this study were highly variable depending on the location (manganese concentration for 4 out of 5 sampling locations. The efficiency of reverse osmosis and ion exchange for total Mn removal was consistently high while activated carbon provided variable results. The four POE greensand filters investigated all increased (29 to 199%) manganese concentration, indicating deficient operation and/or maintenance practices. Manganese concentrations in the distribution system were equal or lower than at the inlet, indicating that sampling at the inlet of the distribution system is conservative. The decline in total Mn concentration was linked to higher water residence time in the distribution system.

  10. Spatial variations in nitrogen dioxide concentrations in an urban area

    Science.gov (United States)

    Nicholas Hewitt, C.

    Fortnightly average NO 2 concentrations have been measured at 49 sites in the small city of Lancaster, U.K., over a continuous 1-year period using passive diffusion tubes. At sampling sites on a congested main road in the city centre considerable spatial and temporal variability in concentrations was found. An annual mean concentration of 63 μgm -3 was found witha range of 12-222 μgm -3. The mean concentration in an adjacent main road was 58 μgm -3 with a range of 5-107 μgm -3. Rather less variability was seen in a suburban main road and in a suburban residential street, which had annual mean concentrations of 38 and 30 μm -3, respectively. Concentrations in a city centre pedestrian precinct decreased with distance from the main road, having an annual mean value of 30μm -3. The data suggest that the precise location of a sampling device may be crucial in determining whether or not a given NO 2, concentration or standard is exceeded.

  11. Variations of the electron concentration in the polar ionosphere

    International Nuclear Information System (INIS)

    Chasovitin, Yu.K.; Shushkova, V.B.

    1980-01-01

    The possibility of constructing an empirical model of electron concentration in the polar ionosphere is considered. The results of rocket measurements carried out at Fort Churchill and on the Hays island at 70-210 km heights are used to analyse the distribution of electron concentration in the non-illuminated sector of the auroral oval, in the subauroral ionosphere and in the polar cap. Taking account of magnetospheric-ionospheric relationships and the geomagnetic environment, certain regularities in the distribution of electron concentration in the polar field, which may serve as a basis for constructing an empirical model of the polar ionosphere have been identified

  12. Time Variations of Macrostickies and Extractable Stickies Concentrations in Deinking

    OpenAIRE

    MacNeil, Donald; Miranda Carreño, Rubén; Monte Lara, María Concepción; Blanco Suárez, Ángeles; Sundberg, Anna

    2010-01-01

    The stickies content, both macrostickies and stickies extractable in a solvent, was determined for samples taken at short time intervals from deinking lines, producing deinked pulp for newsprint production. The study was carried out at three mills on different continents, with each having a different source of recycled paper as raw material. The short-term variations in extractable stickies in the incoming raw material were quite extreme, with differences of 100% being seen within hours. Desp...

  13. Time variations of macro and extractable stickies concentrations in deinking

    OpenAIRE

    McNeil, Donald; Miranda Carreño, Rubén; Concepción Lara, María Concepción; Blanco Suárez, Ángeles; Sundberg, Anna

    2010-01-01

    The stickies content, both macrostickies and stickies extractable in a solvent, was determined for samples taken at short time intervals from deinking lines producing deinked pulp for newsprint production. The study was carried out at three mills on different continents, with each having a different source of recycled paper as raw material. The short-term variations in extractable stickies in the incoming raw material were quite extreme, with differences of 100% being seen within hours. Despi...

  14. 6.6-hour inhalation of ozone concentrations from 60 to 87 parts per billion in healthy humans.

    Science.gov (United States)

    Schelegle, Edward S; Morales, Christopher A; Walby, William F; Marion, Susan; Allen, Roblee P

    2009-08-01

    Identification of the minimal ozone (O(3)) concentration and/or dose that induces measurable lung function decrements in humans is considered in the risk assessment leading to establishing an appropriate National Ambient Air Quality Standard for O(3) that protects public health. To identify and/or predict the minimal mean O(3) concentration that produces a decrement in FEV(1) and symptoms in healthy individuals completing 6.6-hour exposure protocols. Pulmonary function and subjective symptoms were measured in 31 healthy adults (18-25 yr, male and female, nonsmokers) who completed five 6.6-hour chamber exposures: filtered air and four variable hourly patterns with mean O(3) concentrations of 60, 70, 80, and 87 parts per billion (ppb). Compared with filtered air, statistically significant decrements in FEV(1) and increases in total subjective symptoms scores (P < 0.05) were measured after exposure to mean concentrations of 70, 80, and 87 ppb O(3). The mean percent change in FEV(1) (+/-standard error) at the end of each protocol was 0.80 +/- 0.90, -2.72 +/- 1.48, -5.34 +/- 1.42, -7.02 +/- 1.60, and -11.42 +/- 2.20% for exposure to filtered air and 60, 70, 80, and 87 ppb O(3), respectively. Inhalation of 70 ppb O(3) for 6.6 hours, a concentration below the current 8-hour National Ambient Air Quality Standard of 75 ppb, is sufficient to induce statistically significant decrements in FEV(1) in healthy young adults.

  15. Weekday variation in triglyceride concentrations in 1.8 million blood samples

    DEFF Research Database (Denmark)

    Jaskolowski, Jörn; Ritz, Christian; Sjödin, Anders Mikael

    2017-01-01

    BACKGROUND: Triglyceride (TG) concentration is used as a marker of cardio-metabolic risk. However, diurnal and possibly weekday variation exists in TG concentrations. OBJECTIVE: To investigate weekday variation in TG concentrations among 1.8 million blood samples drawn between 2008 and 2015 from...... variations in TG concentrations were recorded for out-patients between the age of 9 to 26 years, with up to 20% higher values on Mondays compared to Fridays (all PTriglyceride concentrations were highest after the weekend and gradually declined during the week. We suggest that unhealthy...

  16. Secular variation of cosmic ray intensity recorded in the radiocarbon concentration of tree rings

    International Nuclear Information System (INIS)

    Kigoshi, K.

    1978-01-01

    Study of the secular variations of cosmic ray intensity on the basis of the secular variations of atmospheric radiocarbon concentration in 8000 years is considered. The data on the radiocarbon concentration is received by three laboratories using the dendrochronologically dated tree ring samples. In order to use the data the variations due to geochemical process must be eliminated. From this point of view the climatic effect on the atmospheric radiocarbon concenttration is estimated using the data on sunspot number and global surface temperature during 1650-1800 y. The barge influence of climate on the atmospheric radiocarbon concentration syggests the small contribution of change of radiocarbon production rate to the short-period fluctuations in the atmospheric radiocarbon concentration. Elimination of variations caused by climate and sunspot activities from the variations in atmospheric radiocarbon concentration gives a long-term scale of its concentration which agrees well to the observed paleo-geomagnetic data

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

    Science.gov (United States)

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

    2018-03-01

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

  18. Seasonal variation in diurnal atmospheric grass pollen concentration profiles

    DEFF Research Database (Denmark)

    Peel, Robert George; Ørby, Pia Viuf; Skjøth, Carsten Ambelas

    2014-01-01

    the time of day when peak concentrations are most likely to occur using seasonally averaged diurnal profiles. Atmospheric pollen loads are highly dependent upon emissions, and different species of grass are known to flower and emit pollen at different times of the day and during different periods......In this study, the diurnal atmospheric grass pollen concentration profile within the Danish city of Aarhus was shown to change in a systematic manner as the pollen season progressed. Although diurnal grass pollen profiles can differ greatly from day-to-day, it is common practice to establish...... of the pollen season. Pollen concentrations are also influenced by meteorological factors - directly through those parameters that govern pollen dispersion and transport, and indirectly through the weather-driven flowering process. We found that three different profiles dominated the grass pollen season...

  19. Parametric modelling of temporal variations in radon concentrations in homes

    International Nuclear Information System (INIS)

    Revzan, K.L.; Turk, B.H.; Harrison, J.; Nero, A.V.; Sextro, R.G.

    1988-01-01

    The 222 Rn concentrations in the living area, the basement, and the undelying soil of a New Jersey home have been measured at half-hour intervals over the course of a year, as have indoor and outdoor temperatures, wind speed and direction, and indoor-outdoor and basement-subslab pressures; in addition, periods of furnace opration have been logged. We generalize and extend an existing radon entry model in order to demonstrate the dependence of the radon concentration on the environmental variales and the extent of furnace use. The model contains parameters which are dependent on geological and structural factors which have not been measured or otherwise determined; statistical methods are used to find the best values of the parameters. The non-linear regression of the model predictions (over time) on the measured living area radon concentrations yields an R/aup 2/ of 0.88. 9 refs., 2 figs

  20. Tritium concentration and variation of environmental water in China

    International Nuclear Information System (INIS)

    Ren Tianshan; Zhao Qiufen; Liu Yan; Chen Bingru; Chen Jiashen; Deng Guolun; Gao Pingying; Kuan Yungu

    2004-01-01

    To estimate the baseline level of tritium concentrations of environmental waters before the operation of the first Chinese nuclear power plant, 1547 water samples of eight categories all over China were sampled in the early 1990s for tritium measurement. The measurements were performed with low background liquid scintillation technology. The average tritium radioactive concentrations were 8.96±4.30, 5.42±0.33, 4.77±1.15, 4.55±0.35, 4.04±0.10, 4.04±0.94, 2.38±0.30, 1.34±0.40 Bq/L for air vapor water, precipitation, river water, lake water, tap water, well water, spring water and sea water, respectively, as listed in Table 1. The results show that the tritium concentations in the early 1990s were significantly lower than that in the 1960s and almost reached to the nature tritium concentrations levels. The index of annual reduction rate of tritium concentrations for most water categories were in the range between -3.1%∼-6.3% in the period of 1978 to 1992, and -4.1%∼-5.7% in the 1990s, however, the averages for air vapor water, precipitation and spring water show slow increase with time in recent years. The regional distribution of tritium concentrations show a tendency being of higher in the north and northwest and lower in the south and southeast, indicating latitude and longitude distribution tendencies. The slopes of tritium concentration-latitude line were in the range of 0.33 - 0.18 (Bq/L)/ degree N for air vapor water, precipitation, river water and spring water, while in the range of 0.012-0.068 (Bq/L)/ degree N. The slopes of tritium concentration-longitude line were in the range of 0.15-0.071 (Bq/L)/ degree E for air vapor water, lake water, tap water and well water, however, the change of tritium concentrations with longitude are not significant. (authors)

  1. Variation of boron concentration in metallic glass ribbons

    International Nuclear Information System (INIS)

    Nagy, A.Z.; Vasvari, B.; Bakos, L.; Duwez, P.; Bogancs, J.; Nazarov, V.M.

    1980-01-01

    The boron concentration of Fe 40 Ni 40 P 14 B 6 , Fe 32 Ni 36 Cr 14 P 12 B 6 and Fe 40 Ni 40 B 20 metallic glasses is measured by neutron activation analysis on both surfaces of the ribbon samples. It is found that the boron concentration is always higher on the bright side of the ribbon than that on the dull side which is in contact with the cold surface of the wheel during the rapid quenching from the melt. A possible explanation is given in terms of the solid-liquid interface moving rapidly from the cooled surface to the free surface when preparing the samples. (author)

  2. Understanding the effectiveness of precursor reductions in lowering 8-hr ozone concentrations--Part II. The eastern United States.

    Science.gov (United States)

    Reynolds, Steven D; Blanchard, Charles L; Ziman, Stephen D

    2004-11-01

    Analyses of ozone (O3) measurements in conjunction with photochemical modeling were used to assess the feasibility of attaining the federal 8-hr O3 standard in the eastern United States. Various combinations of volatile organic compound (VOC) and oxides of nitrogen (NOx) emission reductions were effective in lowering modeled peak 1-hr O3 concentrations. VOC emissions reductions alone had only a modest impact on modeled peak 8-hr O3 concentrations. Anthropogenic NOx emissions reductions of 46-86% of 1996 base case values were needed to reach the level of the 8-hr standard in some areas. As NOx emissions are reduced, O3 production efficiency increases, which accounts for the less than proportional response of calculated 8-hr O3 levels. Such increases in O3 production efficiency also were noted in previous modeling work for central California. O3 production in some urban core areas, such as New York City and Chicago, IL, was found to be VOC-limited. In these areas, moderate NOx emissions reductions may be accompanied by increases in peak 8-hr O3 levels. The findings help to explain differences in historical trends in 1- and 8-hr O3 levels and have serious implications for the feasibility of attaining the 8-hr O3 standard in several areas of the eastern United States.

  3. Effects of short-term abatement measures on peak ozone concentrations during summer smog episodes in the Netherlands

    NARCIS (Netherlands)

    Smeets CJPP; Beck JP; LLO

    2002-01-01

    De afgelopen jaren werden de drempelwaarden voor ozon op grondniveau, zoals vastgelegd in de huidige Richtlijn 92/72/EEC, veelvuldig overschreden in alle landen van de Europese Unie. De EU verplicht alle deelnemende landen om een onderzoek te doen naar het ozon reductie potentieel van korte

  4. Variation of pH-measurement in platelet concentrates

    NARCIS (Netherlands)

    van der Meer, P. F.; van Zanten, A. P.; Pietersz, R. N.; Reesink, H. W.

    2001-01-01

    To measure pH in platelet concentrates, blood gas analysers with different calibration principles may be used. In this study, variances observed in pH measurements with two types of blood gas analysers were investigated. pH was measured in crystalloid solutions (platelet additive solution (PAS-II),

  5. Long-term changes in lower tropospheric baseline ozone concentrations: Comparing chemistry-climate models and observations at northern midlatitudes

    Science.gov (United States)

    Parrish, D. D.; Lamarque, J.-F.; Naik, V.; Horowitz, L.; Shindell, D. T.; Staehelin, J.; Derwent, R.; Cooper, O. R.; Tanimoto, H.; Volz-Thomas, A.; Gilge, S.; Scheel, H.-E.; Steinbacher, M.; Fröhlich, M.

    2014-05-01

    Two recent papers have quantified long-term ozone (O3) changes observed at northern midlatitude sites that are believed to represent baseline (here understood as representative of continental to hemispheric scales) conditions. Three chemistry-climate models (NCAR CAM-chem, GFDL-CM3, and GISS-E2-R) have calculated retrospective tropospheric O3 concentrations as part of the Atmospheric Chemistry and Climate Model Intercomparison Project and Coupled Model Intercomparison Project Phase 5 model intercomparisons. We present an approach for quantitative comparisons of model results with measurements for seasonally averaged O3 concentrations. There is considerable qualitative agreement between the measurements and the models, but there are also substantial and consistent quantitative disagreements. Most notably, models (1) overestimate absolute O3 mixing ratios, on average by 5 to 17 ppbv in the year 2000, (2) capture only 50% of O3 changes observed over the past five to six decades, and little of observed seasonal differences, and (3) capture 25 to 45% of the rate of change of the long-term changes. These disagreements are significant enough to indicate that only limited confidence can be placed on estimates of present-day radiative forcing of tropospheric O3 derived from modeled historic concentration changes and on predicted future O3 concentrations. Evidently our understanding of tropospheric O3, or the incorporation of chemistry and transport processes into current chemical climate models, is incomplete. Modeled O3 trends approximately parallel estimated trends in anthropogenic emissions of NOx, an important O3 precursor, while measured O3 changes increase more rapidly than these emission estimates.

  6. Total column density variations of ozone (O3 O3 O3) in presence of ...

    Indian Academy of Sciences (India)

    −3). In case of O4, an absorbance of. O2–O2 by Greenblatt et al (1990) is calculated as absorbance A is given by: A = σ[O2]2 l,. (2) where l is the optical path length (cm), [O2] is the concentration of oxygen (molecules cm. −3), σ is the absorption cross section with the unit of cm5 molecule. −2. The absorption cross sections of.

  7. Comparison of seasonal variations of ozone exposure and fluxes in a Mediterranean Holm oak forest between the exceptionally dry 2003 and the following year

    International Nuclear Information System (INIS)

    Gerosa, Giacomo; Finco, Angelo; Mereu, Simone; Vitale, Marcello; Manes, Fausto; Denti, Antonio Ballarin

    2009-01-01

    Ozone and energy fluxes have been measured using the eddy covariance technique, from June to December 2004 in Castelporziano near Rome (Italy), and compared to similar measurements made in the previous year. The studied ecosystem consisted in a typical Mediterranean Holm oak forest. Stomatal fluxes have been calculated using the resistance analogy and by inverting the Penmann-Monteith equation. Results showed that the average stomatal contribution accounts for 42.6% of the total fluxes. Non-stomatal deposition proved to be enhanced by increasing leaf wetness and air humidity during the autumnal months. From a comparison of the two years, it can be inferred that water supply is the most important limiting factor for ozone uptake and that prolonged droughts alter significantly the stomatal conductance, even 2 months after the soil water content is replenished. Ozone exposure, expressed as AOT40, behaves similarly to the cumulated stomatal flux in dry conditions whereas a different behaviour for the two indices appears in wet autumnal conditions. A difference also occurs between the two years. - Ozone fluxes to a Holm oak coastal forest show inter-annual variations depending on meteorological conditions and water availability.

  8. Analysis of European ozone trends in the period 1995-2014

    Science.gov (United States)

    Yan, Yingying; Pozzer, Andrea; Ojha, Narendra; Lin, Jintai; Lelieveld, Jos

    2018-04-01

    Surface-based measurements from the EMEP and Airbase networks are used to estimate the changes in surface ozone levels during the 1995-2014 period over Europe. We find significant ozone enhancements (0.20-0.59 µg m-3 yr-1 for the annual means; P-value climate model EMAC, the importance of anthropogenic emissions changes in determining these changes over background sites are investigated. The EMAC model is found to successfully capture the observed temporal variability in mean ozone concentrations, as well as the contrast in the trends of 95th and 5th percentile ozone over Europe. Sensitivity simulations and statistical analysis show that a decrease in European anthropogenic emissions had contrasting effects on surface ozone trends between the 95th and 5th percentile levels and that background ozone levels have been influenced by hemispheric transport, while climate variability generally regulated the inter-annual variations of surface ozone in Europe.

  9. Variation of boron concentration in metallic glass ribbons

    International Nuclear Information System (INIS)

    Nagy, A.Z.; Vasvari, B.; Duwez, P.; Bakos, L.; Seres, Z.; Bogancs, J.; Nazarov, V.M.

    1979-12-01

    The surface boron concentration of Fe 40 Ni 40 P 14 B 6 , Fe 32 Ni 36 Cr 14 P 12 B 6 and Fe 40 Ni 40 B 20 metallic glasses was measured by neutron activation analysis on both sides of the ribbon samples. It was found that the boron concentration is always higher at the bright side of the ribbon than that at the dull side which is in contact with the cold surface of the wheel during the rapid quenching from the melt. A possible explanation is given in terms of the solid-liquid interface moving rapidly from the cooled surface to the free surface when preparing the samples. Range values of alpha-particles for some characteristic compositions of metallic glasses are tabulated. A mathematical technique for the deconvolution of experimental data is described and the listing of the Fortran program is enclosed. (author)

  10. Spatial variations in nitrogen dioxide concentrations in urban Ljubljana, Slovenia

    Directory of Open Access Journals (Sweden)

    Vintar Mally Katja

    2015-09-01

    Full Text Available Ambient nitrogen dioxide (NO2 concentrations are regularly measured at only two monitoring stations in the city centre of Ljubljana, and such scanty data are inadequate for drawing conclusions about spatial patterns of pollution within the city, or to decide on effective measures to further improve air quality. In order to determine the spatial distribution of NO2 concentrations in different types of urban space in Ljubljana, two measuring campaigns throughout the city were carried out, during the summer of 2013 and during the winter of 2014. The main source of NO2 in Ljubljana is road transport. Accordingly, three types of urban space have been identified (urban background, open space along roads, and street canyon, and their NO2 pollution level was measured using Palmes diffusive samplers at a total of 108 measuring spots. This article analyses the results of both measuring campaigns and compares the pollution levels of different types of urban space.

  11. Lithological and seasonal variations in radon concentrations in Cypriot groundwaters

    International Nuclear Information System (INIS)

    Tasoula Kiliari; Anastasia Tsiaili; Ioannis Pashalidis

    2010-01-01

    The paper presents and discusses radon activity concentrations in Cypriot groundwater systems as a function of the background lithology and seasonal/meteorological conditions using an airborne radon monitoring system (ARM) after separation of radon by out-gassing. Radiometric analysis of groundwater samples obtained from non-contaminated systems showed that radon concentration in groundwaters varies strongly (0.1-10 Bq L -1 ) depending mainly on the hosting geological matrix but also to lesser degree on atmospheric/meteorological conditions. The associated excess annual dose has been estimated to range between 10 -6 and 10 -4 mSv y -1 , which is an insignificant contribution to the radiation exposure of the Cypriot population caused by airborne radon (0.5 ± 0.4 mSv y -1 ). (author)

  12. Seasonal variation in radiocesium concentrations in three tree species

    International Nuclear Information System (INIS)

    Garten, C.R. Jr.; Briese, L.A.; Sharitz, R.R.; Gentry, J.B.

    1975-01-01

    Radiocesium concentrations in leaves and stems of black willow (Salix nigra), wax myrtle (Myrica cerifera), and tag alder (Alnus serrulata) trees inhabiting a floodplain contaminated by production-reactor effluents were measured over 1 year. In willow and myrtle trees, leaf radiocesium levels were highest in the spring and declined during the growing season; stem levels remained relatively unchanged or exhibited a slight increase. Seasonal changes in alder tree parts depended on the site examined. The relationship among component parts was essentially consistent across species and collecting sites in the summer. The radiocesium concentrations in order of rank were: roots greater than or equal to leaves greater than stems. Species differences in component-part radiocesium levels were dependent on the part sampled and the collecting site examined. Mean soil to plant-part concentration factors in summer ranged from 0.9 to 7.6, and species means across leaves, stems, and roots averaged 2.1, 3.8, and 6.2 for alder, willow, and myrtle trees, respectively

  13. 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.

  14. 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

  15. The relationship between typhoons' peripheral circulation and ground-level ozone concentrations in central Taiwan.

    Science.gov (United States)

    Cheng, Wan-Li; Lai, Li-Wei; Den, Walter; Wu, Meng-Ting; Hsueh, Chao-An; Lin, Pay-Liam; Pai, Chueh-Ling; Yan, Yeou-Lih

    2014-02-01

    Surface data of meteorological parameters (wind speed, wind direction, and mixing height) and air pollutant concentrations (O3, NO, and NO2) were collected for a 92-day period associated with typhoon formation in 2005. The influence of typhoons on O3 concentration were defined by azimuth and distance from Taiwan, and Types A, B, and C correspond to typhoons less than 1,500 km from Taiwan and located between azimuths 45° and 135°, 135° and 225°, and 225° and 45°, respectively. Type D corresponds to typhoons more than 1,500 km from Taiwan. Titration reactions were conducted at three temporal phases: 2000-0700, 0800-1100, and 1200-1400 LST (Local Standard Time). The air pollution model (TAPM) was used to simulate wind fields and trajectories of air masses. It was determined that typhoon position affected O3 concentration, temporal and spatial patterns of O3 titration and vertical meteorological characteristics, which were not all at the statistically significant level.

  16. 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.

  17. [Indoor volatile organic compounds: concentrations, sources, variation factors].

    Science.gov (United States)

    Palot, A; Charpin-Kadouch, C; Ercoli, J; Charpin, D

    2008-06-01

    Volatile organic compounds (V.O.C.) are part of urban air pollution and are also generated indoors from cleaning and maintenance products. VOC measurements are, on average, 10 times higher within homes than outside. Results of the national survey led by the Observatoire National de la Qualité de l'Air Intérieur demonstrated that up to 25% of French homes have very high or high concentrations of VOC. Indoor levels depend mainly on indoor sources. Aldehydes are included in many everyday life products. VOC originate from various household decorating and cleaning products. Some products are less detrimental to the environment and health and have special labelling. Indoor VOC levels also depend on the rate of air exchange and on household characteristics such as indoor temperature and humidity, age of the building, presence of smokers, and communication with a garage. The public may participate in maintaining good indoor air quality and the authorities should also improve regulations. VOC are part of everyday air pollution. Their sources and concentrations should be better monitored.

  18. Assessing the impacts of current and future concentrations of surface ozone on crop yield with meta-analysis

    Science.gov (United States)

    Feng, Zhaozhong; Kobayashi, Kazuhiko

    Meta-analysis was conducted to quantitatively assess the effects of rising ozone concentrations ([O 3]) on yield and yield components of major food crops: potato, barley, wheat, rice, bean and soybean in 406 experimental observations. Yield loss of the crops under current and future [O 3] was expressed relative to the yield under base [O 3] (≤26 ppb). With potato, current [O 3] (31-50 ppb) reduced the yield by 5.3%, and it reduced the yield of barley, wheat and rice by 8.9%, 9.7% and 17.5%, respectively. In bean and soybean, the yield losses were 19.0% and 7.7%, respectively. Compared with yield loss at current [O 3], future [O 3] (51-75 ppb) drove a further 10% loss in yield of soybean, wheat and rice, and 20% loss in bean. Mass of individual grain, seed, or tuber was often the major cause of the yield loss at current and future [O 3], whereas other yield components also contributed to the yield loss in some cases. No significant difference was found between the responses in crops grown in pots and those in the ground for any yield parameters. The ameliorating effect of elevated [CO 2] was significant in the yields of wheat and potato, and the individual grain weight in wheat exposed to future [O 3]. These findings confirm the rising [O 3] as a threat to food security for the growing global population in this century.

  19. A Case Study On the Relative Influence of Free Tropospheric Subsidence, Long Range Transport and Local Production in Modulating Ozone Concentrations over Qatar

    Science.gov (United States)

    Ayoub, Mohammed; Ackermann, Luis; Fountoukis, Christos; Gladich, Ivan

    2016-04-01

    The Qatar Environment and Energy Research Institute (QEERI) operates a network of air quality monitoring stations (AQMS) around the Doha metropolitan area and an ozonesonde station with regular weekly launches and occasional higher frequency launch experiments (HFLE). Six ozonesondes were launched at 0700 LT/0400 UTC and 1300 LT/1000 UTC over a three day period between 10-12 September, 2013. We present the analysis of the ozonesonde data coupled with regional chemical transport modeling over the same time period using WRF-Chem validated against both the ozonesonde and surface AQMS measurements. The HFLE and modeling show evidence of both subsidence and transboundary transport of ozone during the study period, coupled with a strong sea breeze circulation on the 11th of September resulting in elevated ozone concentrations throughout the boundary layer. The development of the sea breeze during the course of the day and influence of the early morning residual layer versus daytime production is quantified. The almost complete titration of ozone in the morning hours of 11 September, 2013 is attributed to local vehicular emissions of NOx and stable atmospheric conditions prevailing over the Doha area. The relative contribution of long range transport of ozone along the Arabian Gulf coast and local urban emissions are discussed.

  20. Elevated CO2 response of photosynthesis depends on ozone concentration in aspen

    International Nuclear Information System (INIS)

    Noormets, Asko; Kull, Olevi; Sober, Anu; Kubiske, Mark E.; Karnosky, David F.

    2010-01-01

    The effect of elevated CO 2 and O 3 on apparent quantum yield (φ), maximum photosynthesis (P max ), carboxylation efficiency (V cmax ) and electron transport capacity (J max ) at different canopy locations was studied in two aspen (Populus tremuloides) clones of contrasting O 3 tolerance. Local light climate at every leaf was characterized as fraction of above-canopy photosynthetic photon flux density (%PPFD). Elevated CO 2 alone did not affect φ or P max , and increased J max in the O 3 -sensitive, but not in the O 3 -tolerant clone. Elevated O 3 decreased leaf chlorophyll content and all photosynthetic parameters, particularly in the lower canopy, and the negative impact of O 3 increased through time. Significant interaction effect, whereby the negative impact of elevated O 3 was exaggerated by elevated CO 2 was seen in Chl, N and J max , and occurred in both O 3 -tolerant and O 3 -sensitive clones. The clonal differences in the level of CO 2 x O 3 interaction suggest a relationship between photosynthetic acclimation and background O 3 concentration. - Photosynthetic acclimation to elevated CO 2 depends on the background oxidant levels.

  1. 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

  2. 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.

  3. Daily variation of the radon concentration indoors and outdoors and the influence of meteorological parameters

    International Nuclear Information System (INIS)

    Porstendoerfer, J.; Butterweck, G.; Reineking, A.

    1994-01-01

    Series of continuous radon measurements in the open atmosphere and in a dwelling, including the parallel measurement of meteorological parameters, were performed over a period of several weeks. The radon concentration in indoor and outdoor air depends on meteorological conditions. In the open atmosphere the radon concentration varies between 1 and 100 Bq m -3 , depending on weather conditions and time of day. During time periods of low turbulent air exchange (high pressure weather with clear night sky), especially in the night and early morning hours (night inversion layer), the diurnal variation of the radon concentration showed a pronounced maximum. Cloudy and windy weather conditions yield a small diurnal variation of the radon concentration. Indoors, the average level and the diurnal variation of the indoor radon concentration is also influenced by meteorological conditions. The measurements are consistent with a dependence of indoor radon concentrations on indoor-outdoor pressure differences. 11 refs., 4 figs

  4. 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.

  5. Absence of diurnal variation of C-reactive protein concentrations in healthy human subjects

    Science.gov (United States)

    Meier-Ewert, H. K.; Ridker, P. M.; Rifai, N.; Price, N.; Dinges, D. F.; Mullington, J. M.

    2001-01-01

    BACKGROUND: The concentration of C-reactive protein (CRP) in otherwise healthy subjects has been shown to predict future risk of myocardial infarction and stroke. CRP is synthesized by the liver in response to interleukin-6, the serum concentration of which is subject to diurnal variation. METHODS: To examine the existence of a time-of-day effect for baseline CRP values, we determined CRP concentrations in hourly blood samples drawn from healthy subjects (10 males, 3 females; age range, 21-35 years) during a baseline day in a controlled environment (8 h of nighttime sleep). RESULTS: Overall CRP concentrations were low, with only three subjects having CRP concentrations >2 mg/L. Comparison of raw data showed stability of CRP concentrations throughout the 24 h studied. When compared with cutoff values of CRP quintile derived from population-based studies, misclassification of greater than one quintile did not occur as a result of diurnal variation in any of the subjects studied. Nonparametric ANOVA comparing different time points showed no significant differences for both raw and z-transformed data. Analysis for rhythmic diurnal variation using a method fitting a cosine curve to the group data was negative. CONCLUSIONS: Our data show that baseline CRP concentrations are not subject to time-of-day variation and thus help to explain why CRP concentrations are a better predictor of vascular risk than interleukin-6. Determination of CRP for cardiovascular risk prediction may be performed without concern for diurnal variation.

  6. 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

  7. Seasonal variation in concentration of radon and thoron at non-uranium mines in China

    International Nuclear Information System (INIS)

    Cui Hongxing; Wu Yunyun; Zhang Qingzhao; Shang Bing

    2009-01-01

    Objective: To study the seasonal variation in concentrations of radon and thoron in non-uranium mine. Methods: Eight kinds of mineral types from 9 non-uranium mines were selected, including copper, gold, aluminium, manganese, antimonium, tungsten, copper-nickel and coal mines in 6 provinces, such as Yunnan, Shandong, Xinjiang, Heilongjiang, Hunan and Guizhou. LD-P R-T discriminative detectors were used to measure radon and thoron concentrations in underground mines during four seasons in one year. Results: Radon concentrations in underground mines showed a significantly seasonal variation. Radon concentration ranged from 35.5 to 4841 Bq/m 3 in summer, and the average value in four mines exceeded 1000 Bq/m 3 of the control limit for workplace (GB 18871-2002) . In winter, radon concentration ranged from 5 to 1917 Bq/m 3 , only one of them exceeded the control limit. The ratio of radon from summer to winter ranged from 2 to 12. Ventilation was one of the main factors which influenced the seasonal variation of radon. While the thoron concentration in underground mines showed a tendency that it was higher in summer and lower in winter. It was difficult to attain representative values for thoron, due to the influence of location of detectors. The seasonal variation of thoron should be further studied. Conclusions: Seasonal variation for radon and thoron should be taken into account to estimate the effective dose to miners. The values of radon concentration during the short term should be corrected. (authors)

  8. 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....

  9. 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

  10. 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.

  11. Daily and seasonal variations of outdoor alpha-activity concentration in Salzburg city/Austria

    International Nuclear Information System (INIS)

    Lettner, H.; Hubmer, A.K.; Rolle, R.; Winkler, R.; Steinhaeusler, F.

    1996-01-01

    Long-term continuous measurements of the atmospheric outdoor alpha-activity concentration have been performed by using a radioaerosol-monitor, roof-mounted 20 m above ground. The alpha-activity concentration was identified to be predominantly attributed to radon progeny. The total alpha-activity covers a range of two orders of magnitude. Three different components of variations could be identified with regard to temporal variations: Short-term diurnal component (daily variation), mid-term component (days to weeks) and long-term component (seasonal variation). Continuous measurements have been recorded since the end of 1993. The results of continuous measurements of the outdoor alpha-activity concentration over a time span from January 1994 to June 1995 are presented. (author)

  12. Variation in acrylamide concentration in French fries : effects of control measures in food service establishments

    NARCIS (Netherlands)

    Sanny, M.A.I.

    2012-01-01

    The aim of this thesis was first to identify the major technological and managerial factors and to investigate their contribution to variation in acrylamide concentrations. The second aim was to investigate the effect of technological and managerial control measures on the concentration and

  13. Detection of atmospheric tritium by scintillation. Variations in its concentration in France

    International Nuclear Information System (INIS)

    Bibron, R.

    1964-06-01

    The tritium released into the atmosphere as a result of the explosion of thermonuclear devices is a useful radioactive tracer for the study of certain geophysical problems. The low concentrations found however call for the use of extremely sensitive detectors. Two detection methods using liquid scintillators are described. In the first method, the sample is introduced into the scintillator in liquid form, after prior concentration of the tritium by electrolysis. In the second method the tritium is incorporated into the scintillator solvent molecule by chemical synthesis. In the last part of the report are examined the variations in the tritium concentration in rain-water and of the free hydrogen in the air in France. A discussion is then made of the seasonal variations in the case of rain-water and these are compared to the variations in the strontium-90 concentrations. (author) [fr

  14. Temporal variations in elemental concentrations of atmospheric aerosols in Mexico City

    International Nuclear Information System (INIS)

    Aldape U, F.

    1992-05-01

    Measurements are reported of elemental concentrations of airborne particulates in Mexico City and their time variation over a one-week period in the spring of 1988. Proton-induced X-ray emission analysis, PIXE, was used to analyse the atmospheric aerosols which were bombarded with 2.5 MeV protons from the 12 MV Tandem Van de Graaff accelerator at the National Institute of Nuclear Research, ININ. Variations in the elemental concentrations were observed over the time period studied. An intercomparison was made in the case of the element lead with PIXE results obtained at the Crocker Nuclear Laboratory, CNL, University of California for the same set of samples. Excellent agreement was obtained both for the time variation of the relative concentration and the absolute lead concentrations. These results give added confidence to the protocol adopted at ININ. (Author)

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

    DEFF Research Database (Denmark)

    Weschler, Charles J.

    2006-01-01

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

  16. Radon concentration variations between and within buildings of a research institute

    International Nuclear Information System (INIS)

    Antignani, S.; Bochicchio, F.; Ampollini, M.; Venoso, G.; Bruni, B.; Innamorati, S.; Malaguti, L.; Stefano, A.

    2009-01-01

    Radon concentration in indoor air has been measured in many countries in a large number of buildings - mainly in houses but also in apartments and workplaces - mostly as a result of the application of radon policies and regulation requirements. However, few systematic analyses are available on radon concentration variations within buildings and between close buildings, especially as regards workplaces; such variations can have a significant impact on indoor radon exposure evaluation, and ultimately on the assessment of the dose from radon received by workers. Therefore, a project was started in 2006 aimed to study the spatial variation of radon concentration among and within about 40 buildings of the Istituto Superiore di Sanita (ISS), a research institute of public health located in Rome over a small area of less than 1 km 2 . Nuclear track detectors (CR-39) were used to measure radon concentration for two consecutive six-month periods, in more than 700 rooms of the surveyed buildings. The paper describes the project in detail and preliminary results regarding 558 rooms in 29 buildings. Coefficient of variation (CV) was calculated as a measure of relative variation of radon concentration between buildings, between floors, and between rooms on the same floor. The CV between buildings resulted quite high (88%), a lower CV (42%) was found for variation between floors, whereas room-to-room CV on the same floor ranged from 25% at first floor level to 48% at basement level. Floor mean ratios, with ground floor as the reference level, were calculated for each building in order to study the correlation between radon concentration and floor levels. Although no clear trend was observed, the average basement/ground floor ratio of radon concentrations resulted about 2.0, whereas the average sixth floor/ground floor ratio of radon concentrations was 0.5. Some discussion on the potential impact of the results of this study on policies and radon regulations are also included in

  17. Changes in leaf area, nitrogen content and canopy photosynthesis in soybean exposed to an ozone concentration gradient

    Science.gov (United States)

    Influences of ozone (O3) on light-saturated rates of photosynthesis in crop leaves have been well documented. To increase our understanding of O3 effects on individual- or stand level productivity, a mechanistic understanding of factors determining canopy photosynthesis is necessary. We used a canop...

  18. Urban and Rural Ozone Pollution Over Lusaka (Zambia, 15.5S, 25E) During SAFARI-2000 (September 2000)

    Science.gov (United States)

    Thompson, Anne M.; Herman, J. R.; Witte, J. C.; Phahlane, A.; Coetzee, G. J. R.; Mukula, C.; Hudson, R. D.; Frolov, A. D.; Bhartia, P. K. (Technical Monitor)

    2001-01-01

    In early September, throughout south central Africa, seasonal clearing of dry vegetation and the production of charcoal for cooking leads to intense smoke haze and ozone formation. Ozone soundings made over Lusaka during a six-day period in early September 2000 recorded layers of high ozone (greater than 125 ppbv at 5 km) during two stagnant periods, interspersed by a frontal passage that reduced boundary layer ozone by 30 percent. Smoke aerosol column variations aloft and total ozone were monitored by a sun photometer. During the 6-day measurement period, surface ozone concentrations ranged from 50-95 ppbv and integrated tropospheric ozone from the soundings was 39- 54 Dobson Units (note 1.3 km elevation at the launch site). High ozone concentrations above the mixed and inversion layers were advected from rural burning regions in western Zambia where SAFARI aircraft and ground-based instruments observed intense biomass fires and elevated aerosol and trace gas amounts. TOMS tropospheric ozone and smoke aerosols products show the distribution of biomass burning and associated pollution throughout southern Africa in September 2000. Animations of satellite images and trajectories confirm pollutant recirculation over south central African fires, exit of ozone from Mozambique and Tanzania to the Indian Ocean and the characteristic buildup of tropospheric ozone over the Atlantic from western African outflow.

  19. Tree age dependence and within-canopy variation of leaf gas exchange and antioxidative defence in Fagus sylvatica under experimental free-air ozone exposure

    International Nuclear Information System (INIS)

    Herbinger, K.; Then, Ch.; Loew, M.; Haberer, K.; Alexous, M.; Koch, N.; Remele, K.; Heerdt, C.; Grill, D.; Rennenberg, H.; Haeberle, K.-H.; Matyssek, R.; Tausz, M.; Wieser, G.

    2005-01-01

    We characterized leaf gas exchange and antioxidative defence of two-year-old seedlings and 60-year-old trees of Fagus sylvatica exposed to ambient (1xO 3 ) or two-fold ambient (2xO 3 ) O 3 concentrations (maximum of 150 ppb) in a free-air canopy exposure system throughout the growing season. Decline in photosynthesis from sun-exposed to shaded conditions was more pronounced in adult than juvenile trees. Seedling leaves and leaves in the sun-exposed canopy had higher stomatal conductance and higher internal CO 2 concentrations relative to leaves of adult trees and leaves in shaded conditions. There was a weak overall depression of photosynthesis in the 2xO 3 variants across age classes and canopy positions. Pigment and tocopherol concentrations of leaves were significantly affected by canopy position and tree age, whereas differences between 1xO 3 and 2xO 3 regimes were not observed. Glutathione concentrations were significantly increased under 2xO 3 across both age classes and canopy levels. Seedlings differed from adult trees in relevant physiological and biochemical traits in ozone response. The water-soluble antioxidative systems responded most sensitively to 2xO 3 without regard of tree age or canopy position. - Ozone effects on leaf gas exchange and antioxidative systems of beech across tree age and canopy level were investigated in a free air exposure system

  20. Tree age dependence and within-canopy variation of leaf gas exchange and antioxidative defence in Fagus sylvatica under experimental free-air ozone exposure

    Energy Technology Data Exchange (ETDEWEB)

    Herbinger, K. [Institut fuer Pflanzenwissenschaften, Universitaet Graz, Schubertstrasse 51, A-8010 Graz (Austria)]. E-mail: karin.herbinger@uni-graz.at; Then, Ch. [Bundesamt und Forschungszentrum fuer Wald, Abteilung Forstpflanzenphysiologie, Rennweg 1, A-6020 Innsbruck (Austria)]|[Lehrstuhl fuer Oekophysiologie der Pflanzen, Technische Universitaet Muenchen, Life Sciences Center Weihenstephan, Am Hochanger 13, D-85354 Freising (Germany); Loew, M.; Koch, N. [Lehrstuhl fuer Oekophysiologie der Pflanzen, Technische Universitaet Muenchen, Life Sciences Center Weihenstephan, Am Hochanger 13, D-85354 Freising (Germany); Haberer, K.; Alexous, M. [Institut fuer Forstbotanik und Baumphysiologie, Universitaet Freiburg, Georges-Koehler-Allee 053/054, D-79085 Freiburg (Germany); Remele, K. [Institut fuer Pflanzenwissenschaften, Universitaet Graz, Schubertstrasse 51, A-8010 Graz (Austria); Heerdt, C. [Lehrstuhl fuer Bioklimatologie und Immissionsforschung, Technische Universitaet Muenchen, Am Hochanger 13, D-85354 Freising (Germany); Grill, D. [Institut fuer Pflanzenwissenschaften, Universitaet Graz, Schubertstrasse 51, A-8010 Graz (Austria); Rennenberg, H. [Institut fuer Forstbotanik und Baumphysiologie, Universitaet Freiburg, Georges-Koehler-Allee 053/054, D-79085 Freiburg (Germany); Haeberle, K.-H.; Matyssek, R. [Lehrstuhl fuer Oekophysiologie der Pflanzen, Technische Universitaet Muenchen, Life Sciences Center Weihenstephan, Am Hochanger 13, D-85354 Freising (Germany); Tausz, M. [Institut fuer Pflanzenwissenschaften, Universitaet Graz, Schubertstrasse 51, A-8010 Graz (Austria)]|[[School of Forest and Ecosystem Science, University of Melbourne, Water Street, Creswick, Vic. 3363 (Australia); Wieser, G. [Bundesamt und Forschungszentrum fuer Wald, Abteilung Forstpflanzenphysiologie, Rennweg 1, A-6020 Innsbruck (Austria)

    2005-10-15

    We characterized leaf gas exchange and antioxidative defence of two-year-old seedlings and 60-year-old trees of Fagus sylvatica exposed to ambient (1xO{sub 3}) or two-fold ambient (2xO{sub 3}) O{sub 3} concentrations (maximum of 150 ppb) in a free-air canopy exposure system throughout the growing season. Decline in photosynthesis from sun-exposed to shaded conditions was more pronounced in adult than juvenile trees. Seedling leaves and leaves in the sun-exposed canopy had higher stomatal conductance and higher internal CO{sub 2} concentrations relative to leaves of adult trees and leaves in shaded conditions. There was a weak overall depression of photosynthesis in the 2xO{sub 3} variants across age classes and canopy positions. Pigment and tocopherol concentrations of leaves were significantly affected by canopy position and tree age, whereas differences between 1xO{sub 3} and 2xO{sub 3} regimes were not observed. Glutathione concentrations were significantly increased under 2xO{sub 3} across both age classes and canopy levels. Seedlings differed from adult trees in relevant physiological and biochemical traits in ozone response. The water-soluble antioxidative systems responded most sensitively to 2xO{sub 3} without regard of tree age or canopy position. - Ozone effects on leaf gas exchange and antioxidative systems of beech across tree age and canopy level were investigated in a free air exposure system.

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

    Science.gov (United States)

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

    2017-12-01

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

  2. Temporal variation of carbonyl compound concentrations at a semi-rural site in Denmark

    DEFF Research Database (Denmark)

    Christensen, C.S.; Skov, H.; Nielsen, T.

    2000-01-01

    The atmospheric concentrations of formaldehyde, acetaldehyde and acetone were measured by the DNPH-technique at the semi-rural site Lille Valby, Denmark (55 degrees N) between May-July 1995, The average concentrations were observed to be 1.2 ppbv for formaldehyde, 0.8 ppbv for acetaldehyde and 1.......9 ppbv for acetone, For the set of carbonyl compounds, concentrations were found to be highly correlated, though only during daytime, The weak correlations observed during nighttime are believed to be caused by the dry deposition of especially formaldehyde, During periods with low photochemical activity...... of hydrocarbons during long-range transport. Especially, the concentration levels of acetone showed a pronounced seasonal-variation with the highest levels observed during summertime and lowest in winter and spring. The seasonal variation in the concentration levels of formaldehyde and acetaldehyde were small...

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

    Science.gov (United States)

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

    2015-12-01

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

  4. Oxygen vacancies enabled enhancement of catalytic property of Al reduced anatase TiO{sub 2} in the decomposition of high concentration ozone

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Yanhua; Zhang, Xiaolei [Shanghai Institute of Technology, Shanghai 200235 (China); Chen, Li [East China Normal University, Shanghai 200062 (China); Wang, Xiaorui [Shanghai Institute of Technology, Shanghai 200235 (China); Zhang, Na, E-mail: nzhang@sit.edu.cn [Shanghai Institute of Technology, Shanghai 200235 (China); Liu, Yufeng [Shanghai Institute of Technology, Shanghai 200235 (China); Fang, Yongzheng, E-mail: fyz1003@sina.com [Shanghai Institute of Technology, Shanghai 200235 (China)

    2017-06-15

    The catalytic decomposition of gaseous ozone (O{sub 3}) is investigated using anatase TiO{sub 2} (A-TiO{sub 2}) and Aluminum-reduced A-TiO{sub 2} (ARA-TiO{sub 2}) at high concentration and high relative humidity (RH) without light illumination. Compared with the pristine A-TiO{sub 2}, the ARA-TiO{sub 2} sample possesses a unique crystalline core-amorphous shell structure. It is proved to be an excellent solar energy “capture” for solar thermal collectors due to lots of oxygen vacancies. The results indicate that the overall decomposition efficiency of O{sub 3} without any light irradiation has been greatly improved from 4.8% on A-TiO{sub 2} to 100% on ARA-TiO{sub 2} under the RH=100% condition. The ozone conversion over T500/ARA-TiO{sub 2} catalyst is still maintained at 95% after a 72 h test under the reaction condition of 18.5 g/m{sup 3} ozone initial concentration, and RH=90%. The results can be explained that T500/ARA-TiO{sub 2} possesses the largest amorphous contour, the lowest crystallinity, the most surface-active Ti{sup 3+}/T{sup i4+}couples, and the most oxygen vacancies. This result opens a new door to widen the application of TiO{sub 2} in the thermal-catalytic field. - Graphical abstract: The anatase-TiO{sub 2} with various oxidation states and oxygen vacancies have been obtained by aluminum-reduction, and the decomposition efficiency of O{sub 3} has been greatly improved from 4.8% to 100% without irradiation under the RH=100% condition. - Highlights: • The decomposition of gaseous ozone over Al reduced TiO2 (ARA-TiO{sub 2}) is firstly reported. • The decomposition efficiency is up to 100% without any light irradiation on ARA-TiO{sub 2} under RH=100% condition. • The ozone conversion is maintained at 95% after a 72 h test, when C{sub inlet}=18.5 g/m{sup 3} and RH=90%.

  5. Long-memory processes in ozone and temperature variations at the region 60° S–60° N

    Directory of Open Access Journals (Sweden)

    C. Varotsos

    2006-01-01

    Full Text Available Global column ozone and tropospheric temperature observations made by ground-based (1964–2004 and satellite-borne (1978–2004 instrumentation are analyzed. Ozone and temperature fluctuations in small time-intervals are found to be positively correlated to those in larger time-intervals in a power-law fashion. For temperature, the exponent of this dependence is larger in the mid-latitudes than in the tropics at long time scales, while for ozone, the exponent is larger in tropics than in the mid-latitudes. In general, greater persistence could be a result of either stronger positive feedbacks or larger inertia. Therefore, the increased slope of the power distribution of temperature in mid-latitudes at long time scales compared to the slope in the tropics could be connected to the poleward increase in climate sensitivity predicted by the global climate models. The detrended fluctuation analysis of model and observed time series provides a helpful tool for visualizing errors in the treatment of long-range correlations, whose correct modeling would greatly enhance confidence in long-term climate and atmospheric chemistry modeling.

  6. Impact of climate variability on tropospheric ozone

    International Nuclear Information System (INIS)

    Grewe, Volker

    2007-01-01

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

  7. 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

  8. Derivation of the reduced reaction mechanisms of ozone depletion events in the Arctic spring by using concentration sensitivity analysis and principal component analysis

    Directory of Open Access Journals (Sweden)

    L. Cao

    2016-12-01

    Full Text Available The ozone depletion events (ODEs in the springtime Arctic have been investigated since the 1980s. It is found that the depletion of ozone is highly associated with an auto-catalytic reaction cycle, which involves mostly the bromine-containing compounds. Moreover, bromide stored in various substrates in the Arctic such as the underlying surface covered by ice and snow can be also activated by the absorbed HOBr. Subsequently, this leads to an explosive increase of the bromine amount in the troposphere, which is called the “bromine explosion mechanism”. In the present study, a reaction scheme representing the chemistry of ozone depletion and halogen release is processed with two different mechanism reduction approaches, namely, the concentration sensitivity analysis and the principal component analysis. In the concentration sensitivity analysis, the interdependence of the mixing ratios of ozone and principal bromine species on the rate of each reaction in the ODE mechanism is identified. Furthermore, the most influential reactions in different time periods of ODEs are also revealed. By removing 11 reactions with the maximum absolute values of sensitivities lower than 10 %, a reduced reaction mechanism of ODEs is derived. The onsets of each time period of ODEs in simulations using the original reaction mechanism and the reduced reaction mechanism are identical while the maximum deviation of the mixing ratio of principal bromine species between different mechanisms is found to be less than 1 %. By performing the principal component analysis on an array of the sensitivity matrices, the dependence of a particular species concentration on a combination of the reaction rates in the mechanism is revealed. Redundant reactions are indicated by principal components corresponding to small eigenvalues and insignificant elements in principal components with large eigenvalues. Through this investigation, aside from the 11 reactions identified as

  9. 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

  10. Analysis of variation in few-group cross section behavior subjected to burnup and boron concentration

    International Nuclear Information System (INIS)

    Zhang Zongyao; Li Dongsheng.

    1986-01-01

    The paper analyzes the variations of few-group cross section behavior in neutron diffusion subjected to fuel burnup and critical boron concentration in a core. The influences of the behavior on the core excess reactivity, crirical boron concentration, power distribution and the yield of isotopes are also analyzed. A reactor core of samll-medium-sized nuclear power plant is analyzed as an example

  11. Seasonal and diurnal variations in potential alpha energy concentrations at a location in tropical Australia

    International Nuclear Information System (INIS)

    Quintarelli, F.; Akber, R.

    1998-01-01

    Full text: Atmospheric concentrations of radon progeny activity were measured at two locations in tropical Australia during the time period 1992 - 1994. Meteorological parameters including atmospheric pressure, temperature and humidity were also recorded. The data were analysed for seasonal and diurnal variations, in order to establish correlations and associations amongst radon progeny concentrations and meteorological parameters. The paper describes the findings, including the attachment behaviour of radon progeny to ambient aerosol

  12. 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 PM2.5 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 PM2.5, 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 PM2.5 reductions. The annual average 24-h PM2.5 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 PM2.5 by 5 % or 1.0 μg m−3 in the Southeast region.

  13. Investigation of microbial adaptation to salinity variation for treatment of reverse osmosis concentrate by membrane bioreactor

    DEFF Research Database (Denmark)

    Jang, Duksoo; Moon, Chungman; Ahn, Kyuhong

    2014-01-01

    quantitative study on a microbial adaptation strategy for variations on salt concentration (0–20 g/L), lab-scale membrane bioreactors (7L working volume) with polypropylene hollow fiber membrane module (pore size 0.4 μm) were used with different adaptation strategies: instant and stepwise mode. The performance...

  14. Estimating seasonal variations in cloud droplet number concentration over the boreal forest from satellite observations

    NARCIS (Netherlands)

    Janssen, R.; Ganzeveld, L.N.; Kabat, P.; Kulmala, M.; Nieminen, T.; Roebeling, R.A.

    2011-01-01

    Seasonal variations in cloud droplet number concentration (NCD) in low-level stratiform clouds over the boreal forest are estimated from MODIS observations of cloud optical and microphysical properties, using a sub-adiabatic cloud model to interpret vertical profiles of cloud properties. An

  15. Spatial variation of particle number concentration in school microscale environments and its impact on exposure assessment.

    Science.gov (United States)

    Salimi, Farhad; Mazaheri, Mandana; Clifford, Sam; Crilley, Leigh R; Laiman, Rusdin; Morawska, Lidia

    2013-05-21

    It has not yet been established whether the spatial variation of particle number concentration (PNC) within a microscale environment can have an effect on exposure estimation results. In general, the degree of spatial variation within microscale environments remains unclear, since previous studies have only focused on spatial variation within macroscale environments. The aims of this study were to determine the spatial variation of PNC within microscale school environments, in order to assess the importance of the number of monitoring sites on exposure estimation. Furthermore, this paper aims to identify which parameters have the largest influence on spatial variation as well as the relationship between those parameters and spatial variation. Air quality measurements were conducted for two consecutive weeks at each of the 25 schools across Brisbane, Australia. PNC was measured at three sites within the grounds of each school, along with the measurement of meteorological and several other air quality parameters. Traffic density was recorded for the busiest road adjacent to the school. Spatial variation at each school was quantified using coefficient of variation (CV). The portion of CV associated with instrument uncertainty was found to be 0.3, and, therefore, CV was corrected so that only noninstrument uncertainty was analyzed in the data. The median corrected CV (CVc) ranged from 0 to 0.35 across the schools, with 12 schools found to exhibit spatial variation. The study determined the number of required monitoring sites at schools with spatial variability and tested the deviation in exposure estimation arising from using only a single site. Nine schools required two measurement sites and three schools required three sites. Overall, the deviation in exposure estimation from using only one monitoring site was as much as 1 order of magnitude. The study also tested the association of spatial variation with wind speed/direction and traffic density, using partial

  16. 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.

  17. 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

  18. Extreme value modeling for the analysis and prediction of time series of extreme tropospheric ozone levels: a case study.

    Science.gov (United States)

    Escarela, Gabriel

    2012-06-01

    The occurrence of high concentrations of tropospheric ozone is considered as one of the most important issues of air management programs. The prediction of dangerous ozone levels for the public health and the environment, along with the assessment of air quality control programs aimed at reducing their severity, is of considerable interest to the scientific community and to policy makers. The chemical mechanisms of tropospheric ozone formation are complex, and highly variable meteorological conditions contribute additionally to difficulties in accurate study and prediction of high levels of ozone. Statistical methods offer an effective approach to understand the problem and eventually improve the ability to predict maximum levels of ozone. In this paper an extreme value model is developed to study data sets that consist of periodically collected maxima of tropospheric ozone concentrations and meteorological variables. The methods are applied to daily tropospheric ozone maxima in Guadalajara City, Mexico, for the period January 1997 to December 2006. The model adjusts the daily rate of change in ozone for concurrent impacts of seasonality and present and past meteorological conditions, which include surface temperature, wind speed, wind direction, relative humidity, and ozone. The results indicate that trend, annual effects, and key meteorological variables along with some interactions explain the variation in daily ozone maxima. Prediction performance assessments yield reasonably good results.

  19. 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

  20. Seasonal variations of 222Rn concentrations in the air of a tunnel located in Nagano City

    International Nuclear Information System (INIS)

    Muramatsu, H.; Tashiro, Y.; Hasegawa, N.; Misawa, C.; Minami, M.

    2000-01-01

    The survey of 222 Rn concentrations in the air of tunnels constructed during World War II at Nagano City has been performed using a solid-state nuclear track detector technique. Concentrations of several thousands Bq m -3 were observed at inner most areas of the tunnel. A seasonal variation was clearly observed; in summer, several times higher concentrations than in winter were observed, which may be due to a stack effect induced by the temperature difference between the tunnel air and the outside air in each season. The concentrations of radon in the tunnel air decrease exponentially towards the openings of the tunnel, which indicates that the radon concentration in the tunnel is basically governed by diffusion and mixing of radon gas with air. (author)

  1. 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.

  2. Temporal variations of atmospheric CO2 concentration in a temperate deciduous forest in central Japan

    International Nuclear Information System (INIS)

    Murayama, Shohei; Saigusa, Nobuko; Yamamoto, Susumu; Kondo, Hiroaki; Eguchi, Yozo; Chan, Douglas

    2003-01-01

    In order to examine the temporal variation of the atmospheric CO 2 concentration in a temperate deciduous forest, and its relationship with meteorological conditions, continuous measurements of CO 2 and meteorological parameters have been made since 1993 on a tower at Takayama in the central part of Japan. In addition to an average secular increase in atmospheric CO 2 of 1.8 ppm/yr, diurnal variation with a maximum during the night-time to early morning and a minimum in the afternoon is observed from late spring to early fall; the diurnal cycle is not so clearly observed in the remaining seasons of the year. A concentration difference between above and below the canopy, and its diurnal variation, can also be seen clearly in summer. Daily mean concentration data show a prominent seasonal cycle. The maximum and the minimum of the seasonal cycle occur in April and from mid August to mid September, respectively. Day-to-day changes in the diurnal cycle of CO 2 are highly dependent on the day-to-day variations in meteorological conditions. However, CO 2 variations on longer time scales (>10 d) appear to be linearly related to changes in respiration. At Takayama, variations in the 10-d standard deviation of daily mean CO 2 data and 10-d averaged respiration show distinct relationships with soil temperature during spring and fall seasons. In spring, respiration has a stronger exponential dependence on soil temperature than in fall. Interestingly, in summer when soil temperature becomes greater than about 15 deg C, biological respiration becomes more variable and independent of the soil temperature. Thus, at the Takayama site, the Q10 relationship is seasonally dependent, and does not represent well the biological respiration process when the soil temperature rises above 15 deg C

  3. Spatial and temporal variability of tropospheric ozone over Europe

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-12-31

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

  4. Spatial and temporal variability of tropospheric ozone over Europe

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-12-31

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

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

    Science.gov (United States)

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

    2003-04-01

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

  6. Sensitivity of the UAM-predicted ozone concentrations to wind fields in the New York metropolitan area

    Energy Technology Data Exchange (ETDEWEB)

    Sistla, G.; Ku, J.Y.; Zhou, N.; Hao, W.; Rao, S.T. [New York State Dept. of Environmental Conservation, Albany, NY (United States); Thunis, P. [ISPRA Establishment (Italy); Bornstein, R.; Freedman, F. [San Jose State Univ., CA (United States)

    1994-12-31

    The New York airshed modeling domain, extending from northern Philadelphia, PA to the southern Massachusetts, is part of the large urban corridor stretching from Virginia to Maine alone the eastern sea-board of United States. Due to the continued non-attainment of the National Ambient Air Quality Standard (NAAQS) for ozone, the area has been designated to be in the {open_quotes}severe{close_quotes} classification under the 1990 Clean Air Act Amendments. This requires demonstration of compliance with the ozone NAAQS with grid-based photochemical models such as the Urban Airshed Model (UAM). The United States Environmental Protection Agency (USEPA) has recommended the use of a one-way model nesting scheme, with the Regional Oxidant Model (ROM) providing initial and boundary conditions and other ancillary data for the UAM. Meteorological data and emissions data can also be developed by alternative methods for use with UAM, if considered more appropriate than those derived from the ROM-UAM system.

  7. Profiling secondary metabolites of needles of ozone-fumigated white pine (Pinus strobus) clones by thermally assisted hydrolysis/methylation GC/MS.

    Science.gov (United States)

    Shadkami, F; Helleur, R J; Cox, R M

    2007-07-01

    Plant secondary metabolites have an important role in defense responses against herbivores and pathogens, and as a chemical barrier to elevated levels of harmful air pollutants. This study involves the rapid chemical profiling of phenolic and diterpene resin acids in needles of two (ozone-tolerant and ozone-sensitive) white pine (Pinus strobus) clones, fumigated with different ozone levels (control, and daily events peaking at 80 and 200 ppb) for 40 days. The phenolic and resin acids were measured using thermally assisted hydrolysis and methylation (THM) gas chromatography/mass spectrometry. Short-term fumigation affected the levels of two phenolic acids, i.e., 3-hydroxybenzoic and 3,4-dihydroxybenzoic acids, in that both showed a substantial decrease in concentration with increased ozone dose. The decrease in concentration of these THM products may be caused by inhibition of the plant's shikimate biochemical pathway caused by ozone exposure. The combined occurrence of these two ozone-sensitive indicators has a role in biomonitoring of ozone levels and its impact on forest productivity. In addition, chromatographic profile differences in the major diterpene resin acid components were observed between ozone-tolerant and ozone-sensitive clones. The resin acids anticopalic, 3-oxoanticopalic, 3beta-hydroxyanticopalic, and 3,4-cycloanticopalic acids were present in the ozone-sensitive pine; however, only anticopalic acid was present in the ozone-tolerant clone. This phenotypic variation in resin acid composition may be useful in distinguishing populations that are differentially adapted to air pollutants.

  8. Five-year analysis of background carbon dioxide and ozone variations during summer seasons at the Mario Zucchelli station (Antarctica)

    Energy Technology Data Exchange (ETDEWEB)

    Cristofanelli, P.; Calzolari, F.; Bonafe, U.; Lanconelli, C.; Lupi, A.; Busetto, M.; Vitale, V.; Bonasoni, P. (National Research Council, Inst. of Atmospheric Sciences and Climate, Bologna (Italy)), e-mail: p.bonasoni@isac.cnr.it; Colombo, T. (Centro Nazionale di Climatologia e Meteorologia, Italian Air Force, Pratica di Mare (RM) (Italy))

    2011-11-15

    The work focuses on the analysis of CO{sub 2} and O{sub 3} surface variations observed during five summer experimental campaigns carried out at the 'Icaro Camp' clean air facility (74.7 deg S, 164.1 deg E, 41 m a.s.l.) of the 'Mario Zucchelli' Italian coastal research station. This experimental activity allowed the definition of summer average background O{sub 3} values that ranged from 18.3 +- 4.7 ppbv (summer 2005-2006) to 21.3 +- 4.0 ppbv (summer 2003-2004). Background CO{sub 2} concentrations showed an average growth rate of 2.10 ppmv yr-1, with the highest CO{sub 2} increase between the summer campaigns 2002-2003 and 2001-2002 (+2.85 ppmv yr-1), probably reflecting the influence of the 2002/2003 ENSO event. A comparison with other Antarctic coastal sites suggested that the summer background CO{sub 2} and O{sub 3} at MZS-IC are well representative of the average conditions of the Ross Sea coastal regions. As shown by the analysis of local wind direction and by 3-D back-trajectory calculations, the highest CO{sub 2} and O{sub 3} values were recorded in correspondence to air masses flowing from the interior of the Antarctic continent. These results suggest that air mass transport from the interior of the continent exerts an important influence on air mass composition in Antarctic coastal areas

  9. Spatial variation of epoxyscillirosidine concentrations in Moraea pallida (yellow tulp in South Africa

    Directory of Open Access Journals (Sweden)

    Christo J. Botha

    2013-05-01

    Full Text Available Moraea pallida (yellow tulp poisoning is economically the most important intoxication of livestock in South Africa. Poisoning varies according to locality, climatic conditions and growth stage of the plant. The primary objective of this study was to determine the concentration of the toxic principle, epoxyscillirosidine, in yellow tulp leaves and to ascertain the variability of epoxyscillirosidine concentrations within and between different locations. A secondary objective was to utilise Geographic Information Systems in an attempt to explain the variability in toxicity. Flowering yellow tulp plants were collected at 26 sampling points across 20 districts of South Africa. The leaves of five plants per sampling point were extracted and submitted for liquid chromatography/mass spectrometry analysis. A large variation in mean epoxyscillirosidine concentrations, ranging from 3.32 μg/g – 238.27 μg/g, occurred between different geographical regions. The epoxyscillirosidine concentrations also varied tremendously between individual plants (n= 5 collected at the same sampling point, with up to a 24 times difference between the lowest and highest concentration detected. No generalised correlation between epoxyscillirosidine concentrations and soil elemental concentrations could be established. However, samples obtained from the north-eastern part of the sampling region tended to have higher epoxyscillirosidine concentrations compared to samples obtained from the south-western part of the sampling region. Higher toxin concentrations in the northeast were associated with statistically significant higher soil concentrations of iron, bismuth, bromide, cadmium, chromium, rubidium, tellurium, thallium, titanium and zinc, whilst soil concentrations of strontium and soil pH, were significantly lower. This study corroborated the contention that epoxyscillirosidine concentration in yellow tulp fluctuates and may explain the variability in toxicity.

  10. Cadmium speciation and accumulation in periphyton in a small stream with dynamic concentration variations

    Energy Technology Data Exchange (ETDEWEB)

    Bradac, Philippe [Eawag, Swiss Federal Institute of Aquatic Science and Technology, P.O. Box 611, CH-8600 Duebendorf (Switzerland); ETH, Swiss Federal Institute of Technology, Department of Environmental Sciences, CH-8092 Zurich (Switzerland); Wagner, Bettina; Kistler, David; Traber, Jacqueline; Behra, Renata [Eawag, Swiss Federal Institute of Aquatic Science and Technology, P.O. Box 611, CH-8600 Duebendorf (Switzerland); Sigg, Laura, E-mail: laura.sigg@eawag.c [Eawag, Swiss Federal Institute of Aquatic Science and Technology, P.O. Box 611, CH-8600 Duebendorf (Switzerland); ETH, Swiss Federal Institute of Technology, Department of Environmental Sciences, CH-8092 Zurich (Switzerland)

    2010-03-15

    Accumulation of cadmium in periphyton was investigated under field conditions while Cd concentration and speciation were dynamically varying in a small stream during rain events. Speciation in water was determined in situ by diffusion gradient in thin-films (DGT) and by modeling of complexation with fulvic acids. During the rain events, dissolved Cd concentrations increased from 0.17 nM to 0.27-0.36 nM, and 70-97% were DGT-labile. Cd content in periphyton closely followed Cd concentrations in water, despite higher concentrations of Zn and Mn, and may be controlled by either free or DGT-labile Cd concentrations. Decrease of Cd content in periphyton after the rain events was slower than the decrease of Cd concentration in water. Concentrations of Zn, Mn, Cu, Pb and Fe in periphyton also followed the dynamic variations of metal concentrations in water. Repeated exposure of periphyton to elevated dissolved Cd may lead to Cd accumulation. - Cadmium accumulation in periphyton was examined in a small stream during rain events in relation to Cd speciation.

  11. Temporal variations of Escherichia coli concentrations in a large Midwestern river

    Science.gov (United States)

    Schilling, K.E.; Zhang, Y.-K.; Hill, D.R.; Jones, C.S.; Wolter, C.F.

    2009-01-01

    The Raccoon River used by the Des Moines Water Works to serve more than 400,000 people in central Iowa is threatened by contamination from Escherichia coli bacteria from point and nonpoint sources. The 9389 km2 watershed is highly agricultural, with 73% of the land in row crop production and widespread animal production. Results from 2155 grab samples from 1997 to 2005 for E. coli analysis were examined for temporal variations. E. coli concentrations were found to vary across years, seasons, and flow conditions, with a 9-year mean value of 1156 most probable number (MPN)/100 ml. Monthly concentrations exhibited clear seasonality with highest values in May through July. Although E. coli concentrations were higher during periods of greater discharge, the relation of log E. coli to log discharge was not particularly strong (r2 = 0.35). The variogram of E. coli concentrations showed temporal correlation within a span of 4 days suggesting that concentrations measured on 1 day may be related in time to concentrations measured up to 3 days later and beyond 4 days the concentrations vary randomly. The spectral analysis of the time series of E. coli was also carried out and was fitted well with the spectrum of an exponential covariance function. Deciphering temporal patterns and correlation of E. coli bacteria in streams may be useful for developing future monitoring strategies to track concentration patterns and loads. ?? 2008 Elsevier B.V. All rights reserved.

  12. Cadmium speciation and accumulation in periphyton in a small stream with dynamic concentration variations

    International Nuclear Information System (INIS)

    Bradac, Philippe; Wagner, Bettina; Kistler, David; Traber, Jacqueline; Behra, Renata; Sigg, Laura

    2010-01-01

    Accumulation of cadmium in periphyton was investigated under field conditions while Cd concentration and speciation were dynamically varying in a small stream during rain events. Speciation in water was determined in situ by diffusion gradient in thin-films (DGT) and by modeling of complexation with fulvic acids. During the rain events, dissolved Cd concentrations increased from 0.17 nM to 0.27-0.36 nM, and 70-97% were DGT-labile. Cd content in periphyton closely followed Cd concentrations in water, despite higher concentrations of Zn and Mn, and may be controlled by either free or DGT-labile Cd concentrations. Decrease of Cd content in periphyton after the rain events was slower than the decrease of Cd concentration in water. Concentrations of Zn, Mn, Cu, Pb and Fe in periphyton also followed the dynamic variations of metal concentrations in water. Repeated exposure of periphyton to elevated dissolved Cd may lead to Cd accumulation. - Cadmium accumulation in periphyton was examined in a small stream during rain events in relation to Cd speciation.

  13. Genotypic and environmental variation in chromium, cadmium and lead concentrations in rice

    International Nuclear Information System (INIS)

    Zeng Fanrong; Mao Ying; Cheng Wangda; Wu Feibo; Zhang Guoping

    2008-01-01

    Genotypic and environmental variation in Cr, Cd and Pb concentrations of rice grains and the interaction between these metals were investigated by using 138 rice genotypes grown in three contaminated soils. There were significant genotypic differences in the three heavy metal concentrations of rice grains, with the absolute difference among 138 genotypes in grain Cr, Cd and Pb concentrations being 24.5-, 9.1- and 23.8-folds, respectively, under the slightly contaminated soil (containing 4.61 mg kg -1 Cr, 1.09 mg kg -1 Cd and Pb 28.28 mg kg -1 , respectively). A highly significant interaction occurred between genotype and environment (soil type) in the heavy metal concentrations of rice grains. Cr concentration in rice grains was not correlated with Cd and Pb concentration. However, there was a significant correlation between Cd and Pb in slightly and highly contaminated soils. The results suggest the possibility to develop the rice cultivars with low Cd and Pb concentrations in grain. - Some rice genotypes had consistently low grain Cr, Cd and Pb concentrations under the soil with differently contaminated levels

  14. Seasonal variations of radon concentrations in single-family houses with different sub-structures

    DEFF Research Database (Denmark)

    Majborn, B.

    1992-01-01

    Seasonal variations of indoor radon concentrations have been studied in 70 single-family houses selected according to the type of sub-structure and the type of soil underneath the house. Five categories of sub-structure were included - slab-on-grade, crawl space, basement, and combinations...... of basement with slab-on-grade or crawl space. Half of the houses are located on clayey till and the other half on glaciofluvial gravel. In each house radon was measured in a living room and a bedroom, in the basement if present, and in the crawl space if present and accessible. The measurements were made...... with track detectors on a quarterly basis throughout a year. For living rooms and bedrooms the seasonal variations range from being highly significant for the slab-on-grade houses to being insignificant for the crawl space houses. For basements and crawl spaces the geometric mean radon concentrations do...

  15. A study of diurnal variations of radon and thoron concentrations in different indoor environmental conditions

    International Nuclear Information System (INIS)

    Pant, Preeti; Prasad, Mukesh; Ramola, R.C.

    2015-01-01

    The measurements for diurnal variations in radon ( 222 Rn) and thoron ( 220 Rn) concentrations were performed in the different indoor conditions of Tehri Garhwal, Uttarakhand, India by using AlphaGUARD, Portable Radon Monitor and RAD7. While selecting the dwellings, the ventilation conditions, building materials, life style of the inhabitants and their exposure time indoors were also considered. The behavior of indoor radon and thoron concentrations was observed for different type of dwellings with different environmental conditions. The measurement techniques, results obtained and comparison of the results are discussed in details. (author)

  16. Variations of caesium isotope concentrations in air and fallout at Dalat, South Vietnam, 1986-1991

    International Nuclear Information System (INIS)

    Pham Zuy Hien; Nguyen Thanh Binh; Truong Y.; Vuong Thu Bac; Nguyen Trong Ngo.

    1993-01-01

    Monthly records of Cs-137 and Cs-134 concentrations in air and fallout at Dalat for the period 1986-1991 are presented and discussed. The concentration variations exhibit distinct maxima during December-January, when dry fallout dominated. These peaks are explained by the intrusion of more radioactive cold air masses from temperate northern latitudes during the development of large-scale anticyclones frequently observed in the most active winter monsoon period. High dry fallout velocities (about 10 cm/s) determined from this data clearly demonstrate one of the most relevant characteristics of cold air masses: behind the cold front, vertical air motion is descending

  17. Study of temporal variation of radon concentrations in public drinking water supplies

    International Nuclear Information System (INIS)

    York, E.L.

    1995-01-01

    The Environmental Protection Agency (EPA) has proposed a Maximum Contaminant Level (MCL) for radon-222 in public drinking water supplies of 300 pCi/L. Proposed monitoring requirements include collecting quarterly grab samples for the first year, then annual samples for the remainder of the compliance cycle provided first year quarterly samples average below the MCL. The focus of this research was to study the temporal variation of groundwater radon concentrations to investigate how reliably one can predict an annual average radon concentration based on the results of grab samples. Using a open-quotes slow-flowclose quotes collection method and liquid scintillation analysis, biweekly water samples were taken from ten public water supply wells in North Carolina (6 month - 11 month sampling periods). Based on study results, temporal variations exist in groundwater radon concentrations. Statistical analysis performed on the data indicates that grab samples taken from each of the ten wells during the study period would exhibit groundwater radon concentrations within 30% of their average radon concentration

  18. Spatial Variations in N2O Concentration and Isotopomer Composition off the Peru Coast

    Science.gov (United States)

    Bourbonnais, A.; Letscher, R. T.; Kock, A.; Bange, H. W.; Altabet, M. A.

    2016-02-01

    Nitrous oxide (N2O) is a potent greenhouse gas and stratospheric ozone depleting substance. The ocean is an important source of N2O to the atmosphere, accounting for up to about 30% of total emissions. However, the factors controlling N2O production and consumption in oceanic environments are still not understood nor constrained. N2O is a by-product of aerobic nitrification, and is formed by two different pathways: 1) the decomposition of hydroxylamine, an intermediate during ammonium oxidation to nitrite, or 2) the reduction of nitrite to N2O (nitrifier-denitrification). N2O is also an intermediate during denitrification under anoxic conditions. In this study, we measured N2O concentrations and isotopomer ratios, as well as O2, nutrient and biogenic N2 concentrations and the isotopic compositions of nitrate, nitrite and biogenic N2 at several coastal stations during two cruises off the Peru coast (6-14°S, 75-81°W) in December 2012 and January 2013. [N2O] varied from below equilibrium values in the OMZ to up to 238 nmol L-1 at 11 m depth at one of the shallowest stations. The isotopic composition of N2O (bulk δ15N: -5 to 30‰, δ18O: 41 to 95‰, and Site Preference: -3 to 65‰) also varied widely, with important differences between stations. Our results show a strong spatial heterogeneity in the mechanisms controlling N2O production and consumption in coastal upwelling regions, which should be taken into account in oceanic N2O models. We will discuss the contributions from different N2O production processes responsible for the observed extreme N2O accumulations.

  19. Influence of source type and air exchange on variations of indoor radon concentration

    International Nuclear Information System (INIS)

    Arvela, H.; Winqvist, K.

    1986-04-01

    The model relates radon concentration to source strength and its variations, air exchange rate and meteorological factors. Two types of sources have been studied. The pressure difference dependent source is made up of radon transported with soil pore air and driven by pressure difference due to the stack effect. The constant source is made up of radon transported by diffusion from building materials or from soil. The air exchange rate depends exponentially on indoor-outdoor temperature difference and linearly on wind speed. These two inputs have been summed in quadrature. In a house with a constant source radon concentration decreases when the air exchange rate increases due to the increasing temperature difference, whereas the pressure difference dependent source causes an increasing concentration. This is due to the fact that the effect of the source strength increase is stronger than the decreasing effect of air exchange on concentration. The winter-summer concentration ratio depends on the combination of the two types of source. A pure pressure dependent source leads to the winter-summer ratio of 2-3.5 (winter -5 deg C, summer +15 deg C, wind speed 3 m/s). A strong contribution of a constant source is needed to cause a summer concentration higher than the winter concentration. The model is in agreement with the winter-summer concentration ratios measured. This ratio increases with the increasing winter concentration. The measured ratio was near 1.0 for houses with winter concentration of 200 Bq m''3 or less and near 2.0 with concentration of 1000 Bq m''3. In a house with a constant source, the diurnal maximum occurs in the afternoon, while in houses with a pressure difference dependent source the time of maximum is early in the morning

  20. Equatorial ozone profile comparisons using OSO-8 UVMCS and Nimbus 4 BUV data

    Science.gov (United States)

    Aikin, A. C.; Millier, F.; Emery, B.

    1981-01-01

    A comparison is made of equatorial ozone altitude profiles derived from data taken during near-coincident passes of the French solar occultation experiment on OSO-8 and the BUV instrument on Nimbus 4. The period of observation is August through October 1975. OSO-8 data are confined to sunset and the BUV measures ozone during the day for a range of solar zenith angles. Good agreement is found between ozone concentrations from OSO-8 and Nimbus 4 in the region of near overlap, 0.7 mb (52 km). Data indicate that the diurnal variation in ozone below 55 km is less than 20 percent in agreement with current models. The equatorial ozone profile can be described frequently by a single scale height from 34 to 60 km.

  1. Intraspecific variation in 137Cs activity concentration in sporocarps of Suillus variegatus in seven Swedish populations

    International Nuclear Information System (INIS)

    Dahlberg, Anders; Nikolova, Ivanka; Johanson, K.-J.

    1997-01-01

    Following the Chernobyl accident in 1986, sporocarps of Suillus variegatus in Sweden showed a large amount of individual variation in concentration of 137 Cs activity. Our aim was to determine the degrees to which this variability in sporocarp 137 Cs levels could be explained by differences between (i) local populations, (ii) fungal genets and (iii) locations within genets. Five populations in a 100-yr-old Scots pine forest, located within a 1 km 2 area, and two populations in Scots pine/Norway spruce forest, located 40 km north-west of Uppsala, were investigated. In total, 154 sporocarps were analysed to determine their 137 Cs content. Of these, the genetic affiliations of 86 were successfully characterized using somatic incompatibility reactions. Twenty-six genets were found which, on average, consisted of 6.5 sporocarps. The genets averaged 7.5 m in size, measured as the length between the most distant sporocarps. The mean sporocarp 137 Cs level was 67.1 ± 2.8 kBq kgsup(-1) D.W. (range between 13.6 and 182). According to analyses of variance, within-population variation accounted for 60% of the total variation in 137 Cs levels, while 40% was ascribed to variation among populations. Within a population, 137 Cs levels did not generally differ significantly between genets. Plausible reasons for intraspecific variation in radiocaesium content in sporocarps are discussed. (author)

  2. Tetracycline degradation by ozonation in the aqueous phase: Proposed degradation intermediates and pathway

    International Nuclear Information System (INIS)

    Khan, M. Hammad; Bae, Hyokwan; Jung, Jin-Young

    2010-01-01

    During the ozonation of tetracycline (TC) in aqueous media at pHs 2.2 and 7.0, the effects of pH variations, protonation and dissociation of functional groups and variation in free radical exposure were investigated to elucidate the transformation pathway. Liquid chromatography-triple quadrupole mass spectrometry detected around 15 ozonation products, and uncovered their production and subsequent degradation patterns. During ozonation at pH 2.2, the TC degradation pathway was proposed on the basis of the structure, ozonation chemistry and mass spectrometry data of TC. Ozonation of TC at the C11a-C12 and C2-C3 double bonds, aromatic ring and amino group generated products of m/z 461, 477, 509 and 416, respectively. Further ozonation at the above mentioned sites gave products of m/z 432, 480, 448, 525 and 496. The removal of TOC reached a maximum of ∼40% after 2 h of ozonation, while TC was completely removed within 4-6 min at both pHs. The low TOC removal efficiency might be due to the generation of recalcitrant products and the low ozone supply for high TC concentration. Ozonation decreased the acute toxicity of TC faster at pH 7.0 than pH 2.2, but the maximum decrease was only about 40% at both pHs after 2 h of ozonation. In this study, attempts were made to understand the correlation between the transformation products, pathway, acute toxicity and quantity of residual organics in solution. Overall, ozonation was found to be a promising process for removing TC and the products initially generated.

  3. Genotypic and environmental variation in chromium, cadmium and lead concentrations in rice.

    Science.gov (United States)

    Zeng, Fanrong; Mao, Ying; Cheng, Wangda; Wu, Feibo; Zhang, Guoping

    2008-05-01

    Genotypic and environmental variation in Cr, Cd and Pb concentrations of rice grains and the interaction between these metals were investigated by using 138 rice genotypes grown in three contaminated soils. There were significant genotypic differences in the three heavy metal concentrations of rice grains, with the absolute difference among 138 genotypes in grain Cr, Cd and Pb concentrations being 24.5-, 9.1- and 23.8-folds, respectively, under the slightly contaminated soil (containing 4.61mgkg(-1) Cr, 1.09mgkg(-1) Cd and Pb 28.28mgkg(-1), respectively). A highly significant interaction occurred between genotype and environment (soil type) in the heavy metal concentrations of rice grains. Cr concentration in rice grains was not correlated with Cd and Pb concentration. However, there was a significant correlation between Cd and Pb in slightly and highly contaminated soils. The results suggest the possibility to develop the rice cultivars with low Cd and Pb concentrations in grain.

  4. Patterns of Diel Variation in Nitrate Concentrations in the Potomac River

    Science.gov (United States)

    Burns, D. A.; Miller, M. P.; Pellerin, B. A.; Capel, P. D.

    2015-12-01

    The Potomac River is the second largest source of nitrogen to Chesapeake Bay, where reducing nutrient loads has been a focus of efforts to improve estuarine trophic status. Two years of high frequency sensor measurements of nitrate (NO3-) concentrations in the Upper Potomac River at the Little Falls gage were analyzed to quantify seasonal variation in the magnitude and timing of the apparent loss of NO3- from the water column that results from diel-driven processes. In addition to broad seasonal and flow-driven variation in NO3- concentrations, clear diel patterns were evident in the river, especially during low flow conditions that follow stormflow by several days. Diel variation was about 0.01 mg N/L in winter and 0.02 to 0.03 mg N/L in summer with intermediate values during spring and fall. This variation was equivalent to 10% occurred during some summer days. Maximum diel concentrations occurred during mid- to late-morning in most seasons, with the most repeatable patterns in summer and wider variation in timing during fall and winter. Diel NO3- loss diminished loads by about 0.6% in winter and 1.3% in summer, and diel-driven processes were minor compared to estimates of total in-stream NO3- loss that averaged about one-third of the inferred groundwater NO3- contribution to the river network. The magnitude of diel NO3- variation was more strongly related to metrics based on water temperature and discharge than to metrics based on photosynthetically active radiation. Despite the fairly low diminishment of NO3- loads attributable to diel variation, estimates of diel NO3- uptake were fairly high compared to published values from smaller streams and rivers. The diel NO3- patterns observed in the Potomac River are consistent with photosynthesis of periphyton as a principal driver which may be linked to denitrification through the release of labile carbon. The extent to which these diel patterns are related to measures of aquatic metabolism are unknown as is the role

  5. Impacts of interannual variation of the East Asian winter monsoon on aerosol concentrations over eastern China

    Science.gov (United States)

    Zhu, J.; Liao, H.; Li, J.; Feng, J.

    2012-04-01

    China has been experiencing increased concentrations of aerosols, commonly attributed to the large increases in emissions associated with the rapid economic development. We apply a global three-dimensional Goddard Earth Observing System chemical transport model (GEOS-Chem) driven by the NASA/GEOS-4 assimilated meteorological data to quantify the impacts of East Asian winter monsoon (EAWM) on the aerosol concentrations over eastern China. We found that the simulated aerosol concentrations over eastern China have strong interannual variation and negative correlations with the strength of EAWM. Model results show that, accounting for sulfate, nitrate, ammonium, black carbon, and organic carbon aerosols, the winter surface layer PM2.5 concentration averaged over eastern China (110°-125°E, 20°-45°N) can be 17.97% (4.78 µg m-3) higher in the weak monsoon years than that in the strong monsoon years. Regionally, the weakening of EAWM is shown to be able to increase PM2.5 concentration in the middle and lower reach of the Yellow River by 12 µg m-3. This point indicates that climate change associated with variation of EAWM has an essential influence on worsening air quality over eastern China. The possible causes of higher aerosol concentrations in the weak monsoon years may be attributed to the changing in wind fields and planetary boundary layer height between the weak and strong monsoon years. Sensitivity studies are performed to identify the role of chemical reaction associated with temperature and humidity on the higher aerosol concentrations in the weak monsoon years over eastern China.

  6. Temporal Variation of Ambient PM10 Concentration within an Urban-Industrial Environment

    Science.gov (United States)

    Wong, Yoon-Keaw; Noor, Norazian Mohamed; Izzah Mohamad Hashim, Nur

    2018-03-01

    PM10 concentration in the ambient air has been reported to be the main pollutant affecting human health, particularly in the urban areas. This research is conducted to study the variation of PM10 concentration at the three urban-industrial areas in Malaysia, namely Shah Alam, Kuala Terengganu and Melaka. In addition, the association and correlation between PM10 concentration and other air pollutants will be distinguished. Five years interval dataset (2008-2012) consisting of PM10, SOX, NOX and O3 concentrations and other weather parameters such as wind speed, humidity and temperature were obtained from Department of Environment, Malaysia. Shah Alam shows the highest average of PM10 concentration with the value of 62.76 μg/m3 in June, whereas for Kuala Terengganu was 59.29 μg/m3 in February and 46.61 μg/m3 in August for Melaka. Two peaks were observed from the time series plot using the averaged monthly PM10 concentration. First peak occurs when PM10 concentration rises from January to February and the second peak is reached in June and remain high for the next two consecutive months for Shah Alam and Kuala Terengganu. Meanwhile the second peak for Melaka is only achieved in August as a result of the transboundary of smoke from forest fires in the Sumatra region during dry season from May to September. Both of the pollutants can be sourced from rapid industrial activities at Shah Alam. PM10 concentration is strongly correlated with carbon monoxide concentration in Kuala Terengganu and Melaka with value of r2 = 0.1725 and 0.2744 respectively. High carbon monoxide and PM10 concentration are associated with burning of fossil fuel from increased number of vehicles at these areas.

  7. Variation of dissolved organic nitrogen concentration during the ultrasonic pretreatment to Microcystis aeruginosa.

    Science.gov (United States)

    Liu, Cheng; Wang, Jie; Cao, Zhen; Chen, Wei; Bi, Hongkai

    2016-03-01

    Algae cells were the main sources of dissolved organic nitrogen (DON) in raw water with plenty of algae, and ultrasonic pretreatment was one of the algae-controlling methods through the damage of algae cells. However, the variation of DON concentration during the ultrasonic treatment process was not confirmed. Variation of DON concentration during the processes of low frequency ultrasound treatment of Microcystis aeruginosa was investigated. In addition, the effect of sonication on the metabolite concentration, algae cellar activity and the subsequent coagulation performance were discussed. The results showed that after a long duration of ultrasonic (60 s), nearly 90% of the algal cells were damaged and the maximum concentration of DON attained more than 3 mg/L. In order to control the leakage extent of DON, the sonication time should be less than 30 s with power intensity of more than 1.0 W/cm(3). In the mean time, ultrasonic treatment could inhibit the reactivation and the proliferation of algal, keep the algae cell wall integrity and enhance coagulation effectively under the same condition. However, ultrasound frequency had little effect on DON at the frequency range used in this study (20-150 kHz). Copyright © 2015 Elsevier B.V. All rights reserved.

  8. 3D analysis of high ozone production rates observed during the ESCOMPTE campaign

    Science.gov (United States)

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

    2005-03-01

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

  9. 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.

  10. Variation of indoor radon progeny concentration and its role in dose assessment

    International Nuclear Information System (INIS)

    Singh, Manmohan; Singh, Kulwant; Singh, Surinder; Papp, Z.

    2008-01-01

    Instantaneous measurements of equilibrium equivalent concentration of radon (EEC Rn ) were taken over a period of 1 year in 2004 in a typical house at Amritsar city, located in the northwest part of India. A method based on absolute beta counting subsequent to grab aerosol sampling was used. During that year, EEC Rn varied between 1.56 Bq m -3 and 22.77 Bq m -3 with average value of 8.76 Bq m -3 . EEC Rn decreased with the transition from winter to summer and vice versa, having a negative correlation with outdoor temperature. The use of mechanical ventilation, under normal living conditions during summer, caused an extra decrease in the concentrations. The variations with temperature and mechanical ventilation are discussed. Some major issues related to the uncertainties in dose calculations caused by the lack of knowledge of equilibrium factor and ignoring the effect of life style on the radon and its progeny concentrations are discussed

  11. Seasonal variation in the composition and concentration of butyltin compounds in marine fish of Taiwan

    International Nuclear Information System (INIS)

    Dong, C.D.; Chen, C.W.; Liu, L.L.

    2004-01-01

    For the first time, strong evidence is presented to demonstrate that the accumulations of butyltin compounds (BTs) exhibit seasonal variations with respect to their compositions and concentrations in marine fishes. Measurements were made on the benthic ponyfish Leiogenathus splendens and lizardfish Trachinocephalus myops inhabiting the west coast of Taiwan. In the whole body samples of the ponyfish, BT concentrations ranged from 236 to 2501 ng/g wet wt, with those in winter considerably higher than in the other seasons (p summer > spring (p<0.05). Meanwhile, TBT (41%) was predominant in spring, whereas DBT (50 and 68%) was most heavily concentrated in summer and autumn (p<0.001). Seasonally mediated physiological changes, such as dilution due to growth and metabolic compensation, may play important roles in forming different BT accumulation patterns among seasons and organisms

  12. Causes of seasonal variations of Cs-134/137 activity concentrations in surface air

    International Nuclear Information System (INIS)

    Hoetzl, H.; Winkler, R.

    1993-01-01

    In winter months maxima of Cs-134/137 activity concentrations in air are observed at several locations in Europe. To clarify this phenomenon, from October 1991 to November 1992 we performed a program for aerosol collection on a short-term scale based on collecting intervals of 48-72 hours. The local meteorological parameters were determined simultaneously. Statistical analysis of these observations reveiled a highly significant positive correlation between Cs-137 activity concentration and the so-called 'Stagnationsindex'. Based on this relationship the seasonal variations of Cs-134/137 concentrations in ground-level air can be explained by atmospheric inversion conditions frequently occurring during fall- and wintermonths. (orig.) [de

  13. Method for automatic determination of soybean actual evapotranspiration under open top chambers (OTC) subjected to effects of water stress and air ozone concentration.

    Science.gov (United States)

    Rana, Gianfranco; Katerji, Nader; Mastrorilli, Marcello

    2012-10-01

    The present study describes an operational method, based on the Katerji et al. (Eur J Agron 33:218-230, 2010) model, for determining the daily evapotranspiration (ET) for soybean inside open top chambers (OTCs). It includes two functions, calculated day par day, making it possible to separately take into account the effects of concentrations of air ozone and plant water stress. This last function was calibrated in function of the daily values of actual water reserve in the soil. The input variables of the method are (a) the diurnal values of global radiation and temperature, usually measured routinely in a standard weather station; (b) the daily values of the AOT40 index accumulated (accumulated ozone over a threshold of 40 ppb during daylight hours, when global radiation exceeds 50 Wm(-2)) determined inside the OTC; and (c) the actual water reserve in the soil, at the beginning of the trial. The ensemble of these input variables can be automatable; thus, the proposed method could be applied in routine. The ability of the method to take into account contrasting conditions of ozone air concentration and water stress was evaluated over three successive years, for 513 days, in ten crop growth cycles, excluding the days employed to calibrate the method. Tests were carried out in several chambers for each year and take into account the intra- and inter-year variability of ET measured inside the OTCs. On the daily scale, the slope of the linear regression between the ET measured by the soil water balance and that calculated by the proposed method, under different water conditions, are 0.98 and 1.05 for the filtered and unfiltered (or enriched) OTCs with root mean square error (RMSE) equal to 0.77 and 1.07 mm, respectively. On the seasonal scale, the mean difference between measured and calculated ET is equal to +5% and +11% for the filtered and unfiltered OTCs, respectively. The ability of the proposed method to estimate the daily and seasonal ET inside the OTCs is

  14. Seasonal and diurnal variation in concentrations of gaseous and particulate phase endosulfan

    Science.gov (United States)

    Li, Qingbo; Wang, Xianyu; Song, Jing; Sui, Hongqi; Huang, Lei; Li, Lu

    2012-12-01

    Successive 52-week air monitoring of α-endosulfan (α-E), β-endosulfan (β-E) and endosulfan sulfate (E.S) in the gaseous and particulate phases was conducted in Dalian city, northeast China by using an active high-volume sampler. Significant seasonal and diurnal variations in endosulfan concentrations were observed. It was found that the concentration of gaseous-phase α-E peaked in the summer and the concentration of particulate phase α-E peaked in the winter. For E.S, both gaseous and particulate phase concentrations peaked in the summer. α-E was distributed predominantly in the gas phase in the summer but was distributed mainly in the particulate phase in the winter. β-E was distributed mainly in the gas phase in the summer and in the particulate phase at other times of the year. E.S was distributed mainly in the particulate phase throughout the year. Elevated temperatures facilitated the volatilization of α-E from particle surfaces but exerted little effect on β-E and had almost no effect on E.S. Trajectory-based analysis indicates that the seasonal variation in atmospheric concentrations of endosulfan in Dalian city was influenced strongly by the land and sea air masses. In addition, differences in endosulfan concentrations in the particulate phase between day and night were likely due to the circulation of sea/land breezes. The 'cold-condensation' effect occurring during the night may result in the attachment of endosulfan to the particulate phase.

  15. Influence of diurnal variation and fasting on serum iron concentrations in a community-based population.

    Science.gov (United States)

    Nguyen, Leonard T; Buse, Joshua D; Baskin, Leland; Sadrzadeh, S M Hossein; Naugler, Christopher

    2017-12-01

    Serum iron is an important clinical test to help identify cases of iron deficiency or overload. Fluctuations caused by diurnal variation and diet are thought to influence test results, which may affect clinical patient management. We examined the impact of these preanalytical factors on iron concentrations in a large community-based cohort. Serum iron concentration, blood collection time, fasting duration, patient age and sex were obtained for community-based clinical testing from the Laboratory Information Service at Calgary Laboratory Services for the period of January 2011 to December 2015. A total of 276,307 individual test results were obtained. Iron levels were relatively high over a long period from 8:00 to 15:00. Mean concentrations were highest at blood collection times of 11:00 for adult men and 12:00 for adult women and children, however iron levels peaked as late as 15:00 in teenagers. With regard to fasting, iron levels required approximately 5h post-prandial time to return to a baseline, except for children and teenage females where no significant variation was seen until after 11h fasting. After 10h fasting, iron concentrations in all patient groups gradually increased to higher levels compared to earlier fasting times. Serum iron concentrations remain reasonably stable during most daytime hours for testing purposes. In adults, blood collection after 5 to 9h fasting provides a representative estimate of a patient's iron levels. For patients who have fasted overnight, i.e. ≥12h fasting, clinicians should be aware that iron concentrations may be elevated beyond otherwise usual levels. Copyright © 2017. Published by Elsevier Inc.

  16. Preliminary results on variations of radon concentration associated with rock deformation in a uranium mine

    Science.gov (United States)

    Verdoya, Massimo; Bochiolo, Massimo; Chiozzi, Paolo; Pasquale, Vincenzo; Armadillo, Egidio; Rizzello, Daniele; Chiaberto, Enrico

    2013-04-01

    Time-series of radon concentration and environmental parameters were recently recorded in a uranium mine gallery, located in the Maritime Alps (NW Italy). The mine was bored in metarhyolites and porphyric schists mainly composed by quartz, feldspar, sericite and fluorite. U-bearing minerals are generally concentrated in veins heterogeneously spaced and made of crystals of metaautunite and metatorbernite. Radon air concentration monitoring was performed with an ionization chamber which was placed at the bottom of the gallery. Hourly mean values of temperature, pressure, and relative humidity were also measured. External data of atmospheric temperature, pressure and rainfall were also available from a meteorological station located nearby, at a similar altitude of the mine. The analysis of the time series recorded showed variation of radon concentration, of large amplitude, exhibiting daily and half-daily periods, which do not seem correlated with meteorological records. Searching for the origin of radon concentration changes and monitoring their amplitude as a function of time can provide important clues on the complex emanation process. During this process, radon reaches the air- and water-filled interstices by recoil and diffusion, where its migration is directed towards lower concentration regions, following the local gradient. The radon emanation from the rock matrix could also be controlled by stress changes acting on the rate of migration of radon into fissures, and fractures. This may yield emanation boosts due to rock extension and the consequent crack broadening, and emanation decrease when joints between cracks close. Thus, besides interaction and mass transfer with the external atmospheric environment, one possible explanation for the periodic changes in radon concentrations in the investigated mine, could be the variation of rock deformation related to lunar-solar tides. The large variation of concentration could be also due to the fact that the mine is

  17. The influence of variation of deuterium's concentration on the immunity system

    International Nuclear Information System (INIS)

    Tamaian, Radu

    2007-01-01

    Hydrogen's substitution by deuterium represents an environmental alteration at which the organism (in vivo) and the cells (in vitro), respectively, if they can't accommodate will recede. In this way the variations of deuterium's isotopic abundance can be compared with the environmental factors of stress (variations of temperature, quantity of nourishment, radiations, etc). As different forms of existence of life are more or less sensitive at environment's factors variations, so they respond in different ways to concentration variations of deuterium from the living environment/organism. Consequently the mammals' immunity system (IS) presents different feed-backs. The main results are stressed as follows: - a. The use as alimentary adjuvant of deuterium depleted water (DDW) in prolonged periods (21 days) increased the capacity of unspecific immunity defense against the specific bacterial aggression, both in Gram-positive bacteria (Streptococcus pneumoniae558) and of Gram-negative (Klebsiella pneumoniae507); - b. The immunosuppression determined by cyclophosphamide-alquilant agent with medullary depletion of white series reduced the survival of inoculated animals, even in the conditions in which the animals have received dietary supplement with DDW; - c. The immunosuppression through medullary depletion due to irradiation reduced also the survival of inoculated animals, even in the conditions in which the animals have received dietary supplement with DDW. Those mentioned herein lead to the hypothesis that prolonged administration of DDW simulates the unspecific immunity defence, probably through the stimulation of the hematogenic marrow and of lymphopoietic and granulopoietic stem cells. (author)

  18. Ozone production in the reaction of T2 and O2 gas: A comparison of experimental results and model predictions

    International Nuclear Information System (INIS)

    Failor, R.A.; Souers, P.C.; Magnotta, F.

    1992-01-01

    Ozone, predicted to be an important intermediate species in T 2 oxidation, was monitored in situ by UV absorption spectroscopy for 0.01-1.0 mol % T 2 in O 2 (1 atm, 298 K). These are the first measurements of a tritium oxidation reaction intermediate. The experimental results were compared with the predictions of the author's comprehensive model of tritium oxidation. The experimentally determined temporal variation in ozone concentration is qualitatively reproduced by the model. As predicted, the measured initial rate of ozone production varied linearly with the initial T 2 concentration ([T 2 ] o ), but with a value one-third of that predicted. The steady-state ozone concentration ([O 3 ] ss ) a factor of 4 larger than predicted for a 1.0% T 2 -O 2 mixture. Addition of H 2 to the T 2 O 2 mixture, to differentiate between the radiolytic and chemical behavior of the tritium, produced a decrease in [O 3 ] ss which was larger than predicted. Changing the reaction cell surface-to-volume ratio showed indications of minor surface removal of ozone. No reasonable variation in model input parameters brought both the predicted initial ozone production rates and steady-state concentrations of ozone into agreement with the experimental results. Though qualitative agreement was achieved, further studies, with emphasis on surface effects, are necessary to explain quantitative differences and gain a greater understanding of the oxidation mechanism. 27 refs., 11 figs., 4 tabs

  19. Future impacts of distributed power generation on ambient ozone and particulate matter concentrations in the San Joaquin Valley of California.

    Science.gov (United States)

    Vutukuru, Satish; Carreras-Sospedra, Marc; Brouwer, Jacob; Dabdub, Donald

    2011-12-01

    Distributed power generation-electricity generation that is produced by many small stationary power generators distributed throughout an urban air basin-has the potential to supply a significant portion of electricity in future years. As a result, distributed generation may lead to increased pollutant emissions within an urban air basin, which could adversely affect air quality. However, the use of combined heating and power with distributed generation may reduce the energy consumption for space heating and air conditioning, resulting in a net decrease of pollutant and greenhouse gas emissions. This work used a systematic approach based on land-use geographical information system data to determine the spatial and temporal distribution of distributed generation emissions in the San Joaquin Valley Air Basin of California and simulated the potential air quality impacts using state-of-the-art three-dimensional computer models. The evaluation of the potential market penetration of distributed generation focuses on the year 2023. In general, the air quality impacts of distributed generation were found to be small due to the restrictive 2007 California Air Resources Board air emission standards applied to all distributed generation units and due to the use of combined heating and power. Results suggest that if distributed generation units were allowed to emit at the current Best Available Control Technology standards (which are less restrictive than the 2007 California Air Resources Board standards), air quality impacts of distributed generation could compromise compliance with the federal 8-hr average ozone standard in the region.

  20. Modeling the dependency of radon concentration levels inside ancient Egyptian tombs on the ambient temperature variations

    Energy Technology Data Exchange (ETDEWEB)

    Metwally, S M; Abo-Elmagdb, M [Faculty of Science, Department of Physics, Ain Shams University, P. O. Box 11566, Cairo (Egypt); Salamaa, E [National Institute for Standard, Radiation Measurements Department, Cairo (Egypt)

    2007-06-15

    Radon concentration inside partially closed places like dwellings, caves and tombs, depends on many parameters. Some parameters are known quantitatively as radon exhalation rate for walls, decay constant, surface to volume ratio and outdoor concentration while other parameters as ventilation rate is in common known qualitatively due to useless of traditional methods (tracer gases) in many places as ancient Egyptian tombs. This work introduces a derived mathematical model to evaluate the sensitivity of radon concentration levels inside single sided opening places as ancient Egyptian tombs on the ambient temperature differences. The obtained formula for the natural ventilation rate depends on the indoor and outdoor temperature difference and the geometrical dimensions of the doorway. The effects of in and out flow mixing, air viscosity, streamline contraction, swirling flow and turbulence, were taken into consideration in terms of an empirical correction factor. According UNSCEAR reports, the exhalation rate {phi}=C{sub ra}{lambda}{sub rn} f{rho}{sub s}(1-{epsilon})L; C{sub ra} the effective radium content, {lambda}{sub rn} decay constant, f emanation fraction, {rho}{sub s} soil grain density, {epsilon} porosity and L diffusion length, these are approximately static parameters but the variability of ambient temperature introduces a source of energy of fluctuating strength to radon atoms in rocks which controls the flow rate and the ambient content of radon. Therefore, the change of outdoor and indoor temperature difference causes fluctuation of value and direction of volume flow rate in such places consequently causes the daily variation and on average the seasonal variation of radon concentration. Therefore according to the present model, the daily accurate expectation of radon concentrations inside ancient Egyptian tombs, require precise measurements of indoor and outdoor temperatures.

  1. Modeling the dependency of radon concentration levels inside ancient Egyptian tombs on the ambient temperature variations

    International Nuclear Information System (INIS)

    Metwally, S.M.; Abo-Elmagdb, M.; Salamaa, E.

    2007-01-01

    Radon concentration inside partially closed places like dwellings, caves and tombs, depends on many parameters. Some parameters are known quantitatively as radon exhalation rate for walls, decay constant, surface to volume ratio and outdoor concentration while other parameters as ventilation rate is in common known qualitatively due to useless of traditional methods (tracer gases) in many places as ancient Egyptian tombs. This work introduces a derived mathematical model to evaluate the sensitivity of radon concentration levels inside single sided opening places as ancient Egyptian tombs on the ambient temperature differences. The obtained formula for the natural ventilation rate depends on the indoor and outdoor temperature difference and the geometrical dimensions of the doorway. The effects of in and out flow mixing, air viscosity, streamline contraction, swirling flow and turbulence, were taken into consideration in terms of an empirical correction factor. According UNSCEAR reports, the exhalation rate Φ=C ra λ rn fρ s (1-ε)L; C ra the effective radium content, λ rn decay constant, f emanation fraction, ρ s soil grain density, ε porosity and L diffusion length, these are approximately static parameters but the variability of ambient temperature introduces a source of energy of fluctuating strength to radon atoms in rocks which controls the flow rate and the ambient content of radon. Therefore, the change of outdoor and indoor temperature difference causes fluctuation of value and direction of volume flow rate in such places consequently causes the daily variation and on average the seasonal variation of radon concentration. Therefore according to the present model, the daily accurate expectation of radon concentrations inside ancient Egyptian tombs, require precise measurements of indoor and outdoor temperatures

  2. Diurnal variations in H{sub 2}O{sub 2}, O{sub 3}, PAN, HNO{sub 3} and aldehyde concentrations and NO/NO{sub 2} ratios at Rishiri Island, Japan: Potential influence from iodine chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Kanaya, Yugo [Frontier Research Center for Global Change, Japan Agency for Marine-Earth Science and Technology, 3173-25 Showa-machi, Kanazawa-ku, Yokohama, Kanagawa 236-0001 (Japan)]. E-mail: yugo@jamstec.go.jp; Tanimoto, Hiroshi [National Institute for Environmental Studies, Tsukuba (Japan); Matsumoto, Jun [Integrated Research Institute, Tokyo Institute of Technology, Yokohama (Japan); Furutani, Hiroshi [Department of Chemistry and Biochemistry, University of California, San Diego (United States); Hashimoto, Shigeru [National Institute for Environmental Studies, Tsukuba (Japan); Komazaki, Yuichi [Frontier Research Center for Global Change, Japan Agency for Marine-Earth Science and Technology, 3173-25 Showa-machi, Kanazawa-ku, Yokohama, Kanagawa 236-0001 (Japan); Tanaka, Shigeru [Department of Applied Chemistry, Keio University, Yokohama (Japan); Yokouchi, Yoko [National Institute for Environmental Studies, Tsukuba (Japan); Kato, Shungo [Department of Applied Chemistry, Graduate School of Engineering, Tokyo Metropolitan University, Hachioji (Japan); Kajii, Yoshizumi [Department of Applied Chemistry, Graduate School of Engineering, Tokyo Metropolitan University, Hachioji (Japan); Akimoto, Hajime [Frontier Research Center for Global Change, Japan Agency for Marine-Earth Science and Technology, 3173-25 Showa-machi, Kanazawa-ku, Yokohama, Kanagawa 236-0001 (Japan)

    2007-04-15

    The presence of iodine chemistry, hypothesized due to the overprediction of HO{sub 2} levels by a photochemical box model at Rishiri Island in June 2000, was quantitatively tested against the observed NO/NO{sub 2} ratios and the net production rates of ozone. The observed NO/NO{sub 2} ratios were reproduced reasonably well by considering the conversion of NO to NO{sub 2} by IO, whose amount was calculated so as to reproduce the observed HO{sub 2} levels. However, the net production rates of ozone were calculated to be negative when such high mixing ratios of IO were considered, which was inconsistent with the observed buildup of ozone during daytime. These results suggest that iodine chemistry may not be the sole mechanism for the reduced mixing ratios of HO{sub 2}, or that 'hot spots' for iodine chemistry were present. Diurnal variations in the mixing ratios of HCHO, CH{sub 3}CHO, peroxy acetyl nitrate (PAN) and HNO{sub 3} observed during the study are presented along with the simulated ones. The box model simulations suggest that the effect of iodine chemistry on these concentrations is small and that important sources of CH{sub 3}CHO and sinks of PAN are probably missing from our current understanding of the tropospheric chemistry mechanism.

  3. Diurnal variations in H2O2, O3, PAN, HNO3 and aldehyde concentrations and NO/NO2 ratios at Rishiri Island, Japan: Potential influence from iodine chemistry

    International Nuclear Information System (INIS)

    Kanaya, Yugo; Tanimoto, Hiroshi; Matsumoto, Jun; Furutani, Hiroshi; Hashimoto, Shigeru; Komazaki, Yuichi; Tanaka, Shigeru; Yokouchi, Yoko; Kato, Shungo; Kajii, Yoshizumi; Akimoto, Hajime

    2007-01-01

    The presence of iodine chemistry, hypothesized due to the overprediction of HO 2 levels by a photochemical box model at Rishiri Island in June 2000, was quantitatively tested against the observed NO/NO 2 ratios and the net production rates of ozone. The observed NO/NO 2 ratios were reproduced reasonably well by considering the conversion of NO to NO 2 by IO, whose amount was calculated so as to reproduce the observed HO 2 levels. However, the net production rates of ozone were calculated to be negative when such high mixing ratios of IO were considered, which was inconsistent with the observed buildup of ozone during daytime. These results suggest that iodine chemistry may not be the sole mechanism for the reduced mixing ratios of HO 2 , or that 'hot spots' for iodine chemistry were present. Diurnal variations in the mixing ratios of HCHO, CH 3 CHO, peroxy acetyl nitrate (PAN) and HNO 3 observed during the study are presented along with the simulated ones. The box model simulations suggest that the effect of iodine chemistry on these concentrations is small and that important sources of CH 3 CHO and sinks of PAN are probably missing from our current understanding of the tropospheric chemistry mechanism

  4. Monitoring variation in greenhouse gases concentration in urban environment of Delhi.

    Science.gov (United States)

    Sahay, Samraj; Ghosh, Chirashree

    2013-01-01

    Cities across the globe are considered as major anthropogenic sources of greenhouse gases (GHG), yet very few efforts has been made to monitor ambient concentration of GHG in cities, especially in a developing country like India. Here, variations in the ambient concentrations of carbon dioxide (CO(2)) and methane (CH(4)) in residential, commercial, and industrial areas of Delhi are determined from fortnightly daytime observations from July, 2008 to March, 2009. Results indicate that the average daytime ambient concentration of CO(2) varied from 495 to 554 ppm in authorized residential areas, 503 to 621 ppm in the slums or jhuggies in the unauthorized residential areas, 489 to 582 ppm in commercial areas, and 512 to 568 ppm in industrial areas with an average of 541 ± 27 ppm. CH(4) concentration varied from 652 to 5,356 ppbv in authorized residential areas, 500 to 15,220 ppbv in the unauthorized residential areas, 921 to 11,000 ppbv in the commercial areas, and 250 to 2,550 ppbv in the industrial areas with an average of 3,226 ± 1,090 ppbv. A low mid-afternoon CO(2) concentration was observed at most of the sites, primarily due to strong biospheric photosynthesis coupled with strong vertical mixing.

  5. Variation of atmospheric tritium concentration in three chemical forms at Toki, Japan: 2004-12.

    Science.gov (United States)

    Tanaka, M; Uda, T

    2015-11-01

    Atmospheric tritium concentrations of HTO, HT and CH3T have been measured at Toki, Japan, for the environmental impact assessment of tritium for a fusion test facility. According to the data from 2004 to 2012, the concentrations of HT and HTO in water vapour tend to increase in spring. The seasonal variation in HT concentration at Toki was compared with the H2 concentration between 1990 and 2005 at Tae-ahn Peninsula, Republic of Korea, which is at approximately the same latitude as Toki. The monthly average of HT-specific activity varied from 1.24 × 10(5) to 1.76 × 10(5) TU. The peak of the monthly average H2 concentration did not match that of HT. This indicates that the mechanism of the production or the source of HT might be different from the production mechanism of H2. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. Simulation of laminar and turbulent concentric pipe flows with the isogeometric variational multiscale method

    KAUST Repository

    Ghaffari Motlagh, Yousef; Ahn, Hyungtaek; Hughes, Thomas Jr R; Calo, Victor M.

    2013-01-01

    We present an application of the residual-based variational multiscale modeling methodology to the computation of laminar and turbulent concentric annular pipe flows. Isogeometric analysis is utilized for higher-order approximation of the solution using Non-Uniform Rational B-Splines (NURBS). The ability of NURBS to exactly represent curved geometries makes NURBS-based isogeometric analysis attractive for the application to the flow through annular channels. We demonstrate the applicability of the methodology to both laminar and turbulent flow regimes. © 2012 Elsevier Ltd.

  7. AtHMA4 Drives Natural Variation in Leaf Zn Concentration of Arabidopsis thaliana

    Science.gov (United States)

    Chen, Zi-Ru; Kuang, Lu; Gao, Yi-Qun; Wang, Ya-Ling; Salt, David E.; Chao, Dai-Yin

    2018-01-01

    Zinc (Zn) is an essential element for plant growth and development, and Zn derived from crop plants in the diet is also important for human health. Here, we report that genetic variation in Heavy Metal-ATPase 4 (HMA4) controls natural variation in leaf Zn content. Investigation of the natural variation in leaf Zn content in a world-wide collection of 349 Arabidopsis thaliana wild collected accessions identified two accessions, Van-0 and Fab-2, which accumulate significantly lower Zn when compared with Col-0. Both quantitative trait loci (QTL) analysis and bulked segregant analysis (BSA) identified HMA4 as a strong candidate accounting for this variation in leaf Zn concentration. Genetic complementation experiments confirmed this hypothesis. Sequence analysis revealed that a 1-bp deletion in the third exon of HMA4 from Fab-2 is responsible for the lose of function of HMA4 driving the low Zn observed in Fab-2. Unlike in Fab-2 polymorphisms in the promoter region were found to be responsible for the weak function of HMA4 in Van-0. This is supported by both an expression analysis of HMA4 in Van-0 and through a series of T-DNA insertion mutants which generate truncated HMA4 promoters in the Col-0 background. In addition, we also observed that Fab-2, Van-0 and the hma4-2 null mutant in the Col-0 background show enhanced resistance to a combination of high Zn and high Cd in the growth medium, raising the possibility that variation at HMA4 may play a role in environmental adaptation. PMID:29545819

  8. AtHMA4 Drives Natural Variation in Leaf Zn Concentration of Arabidopsis thaliana.

    Science.gov (United States)

    Chen, Zi-Ru; Kuang, Lu; Gao, Yi-Qun; Wang, Ya-Ling; Salt, David E; Chao, Dai-Yin

    2018-01-01

    Zinc (Zn) is an essential element for plant growth and development, and Zn derived from crop plants in the diet is also important for human health. Here, we report that genetic variation in Heavy Metal-ATPase 4 ( HMA4 ) controls natural variation in leaf Zn content. Investigation of the natural variation in leaf Zn content in a world-wide collection of 349 Arabidopsis thaliana wild collected accessions identified two accessions, Van-0 and Fab-2, which accumulate significantly lower Zn when compared with Col-0. Both quantitative trait loci (QTL) analysis and bulked segregant analysis (BSA) identified HMA4 as a strong candidate accounting for this variation in leaf Zn concentration. Genetic complementation experiments confirmed this hypothesis. Sequence analysis revealed that a 1-bp deletion in the third exon of HMA4 from Fab-2 is responsible for the lose of function of HMA4 driving the low Zn observed in Fab-2. Unlike in Fab-2 polymorphisms in the promoter region were found to be responsible for the weak function of HMA4 in Van-0. This is supported by both an expression analysis of HMA4 in Van-0 and through a series of T-DNA insertion mutants which generate truncated HMA4 promoters in the Col-0 background. In addition, we also observed that Fab-2, Van-0 and the hma4-2 null mutant in the Col-0 background show enhanced resistance to a combination of high Zn and high Cd in the growth medium, raising the possibility that variation at HMA4 may play a role in environmental adaptation.

  9. Dynamics of ozone layer under Serbia and solar activity: Previous statement

    Directory of Open Access Journals (Sweden)

    Ducić Vladan

    2008-01-01

    Full Text Available The aim of this paper is to identify ozone layer dynamics under Serbian area, as well as possible relations of change in stratospheric ozone concentration with some parameters of solar activity. During the period 1979-2005, the statistical decrease of ozone concentration was noticed under Serbian territory cumulatively for 24.5 DU (7.2%, apropos 9.4 DU (2.8% by decade. These changes are consistent with the changes in surrounding countries. From absolute minimum 1993, flexible trend of ozone layer pentad values validate hypotheses of its recovery. Correspondence of ozone thickness extreme period with Wolf's number and with the greatest volcanic eruptions shows that interannual variations of stratospheric ozone concentration are still in the function of natural factors above all, as are solar and volcanic activities. Investigation of larger number solar activity parameters shows statistically important antiphase synchronous between the number of polar faculae on the Sun and stratospheric ozone dynamics under Serbia. Respecting that relation between these two features until now isn't depicted, some possible causal mechanisms are proposed.

  10. Variations in time and space of trace metal aerosol concentrations in urban areas and their surroundings

    Science.gov (United States)

    Moreno, T.; Querol, X.; Alastuey, A.; Reche, C.; Cusack, M.; Amato, F.; Pandolfi, M.; Pey, J.; Richard, A.; Prévôt, A. S. H.; Furger, M.; Gibbons, W.

    2011-09-01

    Using an unprecedentedly large geochemical database, we compare temporal and spatial variations in inhalable trace metal background concentrations in a major city (Barcelona, Spain) and at a nearby mountainous site (Montseny) affected by the urban plume. Both sites are contaminated by technogenic metals, with V, Pb, Cu, Zn, Mn, Sn, Bi, Sb and Cd all showing upper continental crust (UCC) normalised values >1 in broadly increasing order. The highest metal concentrations usually occur during winter at Barcelona and summer in Montseny. This seasonal difference was especially marked at the remote mountain site in several elements such as Ti and Rare Earth Elements, which recorded campaign maxima, exceeding PM10 concentrations seen in Barcelona. The most common metals were Zn, Ti, Cu, Mn, Pb and V. Both V and Ni show highest concentrations in summer, and preferentially fractionate into the finest PM sizes (PM1/PM10 > 0.5) especially in Barcelona, this being attributed to regionally dispersed contamination from fuel oil combustion point sources. Within the city, hourly metal concentrations are controlled either by traffic (rush hour double peak for Cu, Sb, Sn, Ba) or industrial plumes (morning peak of Ni, Mn, Cr generated outside the city overnight), whereas at Montseny metal concentrations rise during the morning to a single, prolonged afternoon peak as contaminated air transported by the sea breeze moves into the mountains. Our exceptional database, which includes hourly measurements of chemical concentrations, demonstrates in more detail than previous studies the spatial and temporal variability of urban pollution by trace metals in a given city. Technogenic metalliferous aerosols are commonly fine in size and therefore potentially bioavailable, emphasising the case for basing urban background PM characterisation not only on physical parameters such as mass but also on sample chemistry and with special emphasis on trace metal content.

  11. Temporal multiscaling characteristics of particulate matter PM 10 and ground-level ozone O3 concentrations in Caribbean region

    Science.gov (United States)

    Plocoste, Thomas; Calif, Rudy; Jacoby-Koaly, Sandra

    2017-11-01

    A good knowledge of the intermittency of atmospheric pollutants is crucial for air pollution management. We consider here particulate matter PM 10 and ground-level ozone O3 time series in Guadeloupe archipelago which experiments a tropical and humid climate in the Caribbean zone. The aim of this paper is to study their scaling statistics in the framework of fully developed turbulence and Kolmogorov's theory. Firstly, we estimate their Fourier power spectra and consider their scaling properties in the physical space. The power spectra computed follows a power law behavior for both considered pollutants. Thereafter we study the scaling behavior of PM 10 and O3 time series. Contrary to numerous studies where the multifractal detrended fluctuation analysis is frequently applied, here, the classical structure function analysis is used to extract the scaling exponent or multifractal spectrum ζ(q) ; this function provides a full characterization of a process at all intensities and all scales. The obtained results show that PM 10 and O3 possess intermittent and multifractal properties. The singularity spectrum MS(α) also confirms both pollutants multifractal features. The originality of this work comes from a statistical modeling performed on ζ(q) and MS(α) by a lognormal model to compute the intermittency parameter μ. By contrast with PM 10 which mainly depends on puffs of Saharan dust (synoptic-scale), O3 is more intermittent due to variability of its local precursors. The results presented in this paper can help to better understand the mechanisms governing the dynamics of PM 10 and O3 in Caribbean islands context.

  12. 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).

  13. Lower tropospheric ozone over India and its linkage to the South Asian monsoon

    Science.gov (United States)

    Lu, Xiao; Zhang, Lin; Liu, Xiong; Gao, Meng; Zhao, Yuanhong; Shao, Jingyuan

    2018-03-01

    Lower tropospheric (surface to 600 hPa) ozone over India poses serious risks to both human health and crops, and potentially affects global ozone distribution through frequent deep convection in tropical regions. Our current understanding of the processes controlling seasonal and long-term variations in lower tropospheric ozone over this region is rather limited due to spatially and temporally sparse observations. Here we present an integrated process analysis of the seasonal cycle, interannual variability, and long-term trends of lower tropospheric ozone over India and its linkage to the South Asian monsoon using the Ozone Monitoring Instrument (OMI) satellite observations for years 2006-2014 interpreted with a global chemical transport model (GEOS-Chem) simulation for 1990-2010. OMI observed lower tropospheric ozone over India averaged for 2006-2010, showing the highest concentrations (54.1 ppbv) in the pre-summer monsoon season (May) and the lowest concentrations (40.5 ppbv) in the summer monsoon season (August). Process analyses in GEOS-Chem show that hot and dry meteorological conditions and active biomass burning together contribute to 5.8 Tg more ozone being produced in the lower troposphere in India in May than January. The onset of the summer monsoon brings ozone-unfavorable meteorological conditions and strong upward transport, which all lead to large decreases in the lower tropospheric ozone burden. Interannually, we find that both OMI and GEOS-Chem indicate strong positive correlations (r = 0.55-0.58) between ozone and surface temperature in pre-summer monsoon seasons, with larger correlations found in high NOx emission regions reflecting NOx-limited production conditions. Summer monsoon seasonal mean ozone levels are strongly controlled by monsoon strengths. Lower ozone concentrations are found in stronger monsoon seasons mainly due to less ozone net chemical production. Furthermore, model simulations over 1990-2010 estimate a mean annual trend of 0

  14. The impact of nudging coefficient for the initialization on the atmospheric flow field and the photochemical ozone concentration of Seoul, Korea

    Science.gov (United States)

    Choi, Hyun-Jung; Lee, Hwa Woon; Sung, Kyoung-Hee; Kim, Min-Jung; Kim, Yoo-Keun; Jung, Woo-Sik

    In order to incorporate correctly the large or local scale circulation in the model, a nudging term is introduced into the equation of motion. Nudging effects should be included properly in the model to reduce the uncertainties and improve the air flow field. To improve the meteorological components, the nudging coefficient should perform the adequate influence on complex area for the model initialization technique which related to data reliability and error suppression. Several numerical experiments have been undertaken in order to evaluate the effects on air quality modeling by comparing the performance of the meteorological result with variable nudging coefficient experiment. All experiments are calculated by the upper wind conditions (synoptic or asynoptic condition), respectively. Consequently, it is important to examine the model response to nudging effect of wind and mass information. The MM5-CMAQ model was used to assess the ozone differences in each case, during the episode day in Seoul, Korea and we revealed that there were large differences in the ozone concentration for each run. These results suggest that for the appropriate simulation of large or small-scale circulations, nudging considering the synoptic and asynoptic nudging coefficient does have a clear advantage over dynamic initialization, so appropriate limitation of these nudging coefficient values on its upper wind conditions is necessary before making an assessment. The statistical verifications showed that adequate nudging coefficient for both wind and temperature data throughout the model had a consistently positive impact on the atmospheric and air quality field. On the case dominated by large-scale circulation, a large nudging coefficient shows a minor improvement in the atmospheric and air quality field. However, when small-scale convection is present, the large nudging coefficient produces consistent improvement in the atmospheric and air quality field.

  15. Experimental Study of Hydroxy Gas (HHO) Production with Variation in Current, Voltage and Electrolyte Concentration

    Science.gov (United States)

    Alam, Noor; Pandey, K. M.

    2017-08-01

    In this paper, work has been carried out experimentally for the investigation of the effects of variation incurrent, voltage, temperature, chemical concentration and reaction time on the amount of hydroxy gas produced. Further effects on the overall electrolysis efficiency of advance alkaline water is also studied. The hydroxy gas (HHO) has been produced experimentally by the electrolysis of alkaline water with parallel plate electrode of 316L-grade stainless steel. The electrode has been selected on the basis of corrosion resistance and inertness with respect to electrolyte (KOH). The process used for the production of HHO is conventional as compared to the other production processes because of reduced energy consumption, less maintenance and low setup cost. From the experimental results, it has been observed that with increase in voltage, temperature and electrolyte concentration of alkaline solution, the production of hydroxy gas has increased about 30 to 40% with reduction in electrical energy consumption.

  16. New Silica Magnetite Sorbent: The Influence of Variations of Sodium Silicate Concentrations on Silica Magnetite Character

    Science.gov (United States)

    Azmiyawati, C.; Pratiwi, P. I.; Darmawan, A.

    2018-04-01

    The adsorption capacity of an adsorbent is determined by the adsorbent and the adsorbate properties. The character of the adsorbent will play a major role in its ability to adsorb the corresponding adsorbate. Therefore, in this study we looked at the effects of variations of sodium silicate concentrations on the resulting magnetite silica adsorbent properties. The application of silica coating on the magnetite was carried out through a sol-gel process with sodium silicate and HCl precursors. Based on the characterization data obtained, it was found that the silica coating on magnetite can increase the resistance to acid leaching, increase the particle size, but decrease the magnetic properties of the magnetite. Based on Gas Sorption Analyzer (GSA) and X-ray Difraction (XRD) data it can successively be determined that increase in concentration of sodium silicate will increase the surface area and amorphous structure of the Silica Magnetie.

  17. Monitoring of the ozone layer. Annual report 1997

    International Nuclear Information System (INIS)

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

    1998-10-01

    . SAOZ (System for Analysis of Observations at Zenith) equipment has been used at Ny-Aalesund since 1990 and is in fairly good agreement with other more traditional instrumentation. The ozone registration equipment at the Andoeya is used for measuring rapid variations in the vertical ozone concentration distribution

  18. Cow and herd variation in milk urea nitrogen concentrations in lactating dairy cattle.

    Science.gov (United States)

    Aguilar, M; Hanigan, M D; Tucker, H A; Jones, B L; Garbade, S K; McGilliard, M L; Stallings, C C; Knowlton, K F; James, R E

    2012-12-01

    Milk urea nitrogen (MUN) is correlated with N balance, N intake, and dietary N content, and thus is a good indicator of proper feeding management with respect to protein. It is commonly used to monitor feeding programs to achieve environmental goals; however, genetic diversity also exists among cows. It was hypothesized that phenotypic diversity among cows could bias feed management decisions when monitoring tools do not consider genetic diversity associated with MUN. The objective of the work was to evaluate the effect of cow and herd variation on MUN. Data from 2 previously published research trials and a field trial were subjected to multivariate regression analyses using a mixed model. Analyses of the research trial data showed that MUN concentrations could be predicted equally well from diet composition, milk yield, and milk components regardless of whether dry matter intake was included in the regression model. This indicated that cow and herd variation could be accurately estimated from field trial data when feed intake was not known. Milk urea N was correlated with dietary protein and neutral detergent fiber content, milk yield, milk protein content, and days in milk for both data sets. Cow was a highly significant determinant of MUN regardless of the data set used, and herd trended to significance for the field trial data. When all other variables were held constant, a percentage unit change in dietary protein concentration resulted in a 1.1mg/dL change in MUN. Least squares means estimates of MUN concentrations across herds ranged from a low of 13.6 mg/dL to a high of 17.3 mg/dL. If the observed MUN for the high herd were caused solely by high crude protein feeding, then the herd would have to reduce dietary protein to a concentration of 12.8% of dry matter to achieve a MUN concentration of 12 mg/dL, likely resulting in lost milk production. If the observed phenotypic variation is due to genetic differences among cows, genetic choices could result in

  19. Exploring spatial and temporal variations of cadmium concentrations in pacific oysters from british columbia.

    Science.gov (United States)

    Feng, Cindy Xin; Cao, Jiguo; Bendell, Leah

    2011-09-01

    Oysters from the Pacific Northwest coast of British Columbia, Canada, contain high levels of cadmium, in some cases exceeding some international food safety guidelines. A primary goal of this article is the investigation of the spatial and temporal variation in cadmium concentrations for oysters sampled from coastal British Columbia. Such information is important so that recommendations can be made as to where and when oysters can be cultured such that accumulation of cadmium within these oysters is minimized. Some modern statistical methods are applied to achieve this goal, including monotone spline smoothing, functional principal component analysis, and semi-parametric additive modeling. Oyster growth rates are estimated as the first derivatives of the monotone smoothing growth curves. Some important patterns in cadmium accumulation by oysters are observed. For example, most inland regions tend to have a higher level of cadmium concentration than most coastal regions, so more caution needs to be taken for shellfish aquaculture practices occurring in the inland regions. The semi-parametric additive modeling shows that oyster cadmium concentration decreases with oyster length, and oysters sampled at 7 m have higher average cadmium concentration than those sampled at 1 m. © 2010, The International Biometric Society.

  20. 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.

  1. Time resolved FTIR study of the catalytic CO oxidation under periodic variation of the reactant concentration

    Energy Technology Data Exchange (ETDEWEB)

    Kritzenberger, J; Wokaun, A [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    Oxidation of CO over palladium/zirconia catalyst obtained from an amorphous Pd{sub 25}Zr{sub 75} precursor was investigated by time resolved FTIR spectroscopy. Sine wave shaped modulation of the reactant concentration, i.e. variation of CO or O{sub 2} partial pressure, was used to induce variations of the IR signals of product (CO{sub 2}) and unconverted reactant (CO), which were detected in a multi-pass absorption cell. The phase shift {phi} between external perturbation and variation of the CO{sub 2} signal was examined in dependence on temperature (100{sup o}C{<=}T{<=}350{sup o}C) and modulation frequency (1.39x10{sup -4}Hz{<=}{omega}{<=}6.67x10{sup -2}Hz). From the phase shift values, a simple Eley-Rideal mechanism is excluded, and the rate limiting step of the Langmuir-Hinshelwood mechanism for the CO oxidation may be identified. Adsorption and possible surface movement of CO to the actual reaction site determine the rate of the CO oxidation on the palladium/zirconia catalyst used in our study. The introduction of an external perturbation is a first step towards the application of two-dimensional infrared spectroscopy to heterogeneous catalyzed reactions. (author) 3 figs., 4 refs.

  2. [Mechanism of catalytic ozonation for the degradation of paracetamol by activated carbon].

    Science.gov (United States)

    Wang, Jia-Yu; Dai, Qi-Zhou; Yu, Jie; Yan, Yi-Zhou; Chen, Jian-Meng

    2013-04-01

    The degradation of paracetamol (APAP) in aqueous solution was studied with ozonation integrated with activated carbon (AC). The synergistic effect of ozonation/AC process was explored by comparing the degradation efficiency of APAP in three processes (ozonation alone, activated carbon alone and ozonation integrated with activated carbon). The operational parameters that affected the reaction rate were carefully optimized. Based on the intermediates detected, the possible pathway for catalytic degradation was discussed and the reaction mechanism was also investigated. The results showed that the TOC removal reached 55.11% at 60 min in the AC/O3 system, and was significantly better than the sum of ozonation alone (20.22%) and activated carbon alone (27.39%), showing the great synergistic effect. And the BOD5/COD ratio increased from 0.086 (before reaction) to 0.543 (after reaction), indicating that the biodegradability was also greatly improved. The effects of the initial concentration of APAP, pH value, ozone dosage and AC dosage on the variation of reaction rate were carefully discussed. The catalytic reaction mechanism was different at different pH values: the organic pollutions were removed by adsorption and direct ozone oxidation at acidic pH, and mainly by catalytic ozonation at alkaline pH.

  3. The Influence of Variation in Time and HCl Concentration to the Glucose Produced from Kepok Banana

    Science.gov (United States)

    Widodo M, Rohman; Noviyanto, Denny; RM, Faisal

    2016-01-01

    Kepok banana (Musa paradisiaca) is a plant that has many advantagesfrom its fruit, stems, leaves, flowers and cob. However, we just tend to take benefit from the fruit. We grow and harvest the fruit without taking advantages from other parts. So they would be a waste or detrimental to animal nest if not used. The idea to take the benefit from the banana crop yields, especially cob is rarely explored. This study is an introduction to the use of banana weevil especially from the glucose it contains. This study uses current methods of hydrolysis using HCl as a catalyst with the concentration variation of 0.4 N, 0.6 N and 0.8 N and hydrolysis times variation of 20 minutes, 25 minutes and 30 minutes. The stages in the hydrolysis include preparation of materials, the process of hydrolysis and analysis of test results using Fehling and titrate with standard glucose solution. HCl is used as a catalyst because it is cheaper than the enzyme that has the same function. NaOH 60% is used for neutralizing the pH of the filtrate result of hydrolysis. From the results of analysis, known thatthe biggest yield of glucose is at concentration 0.8 N and at 30 minutes reaction, it contains 6.25 gram glucose / 20 gram dry sampel, and the convertion is 27.22% at 20 gram dry sampel.

  4. Variations in 137Cs activity concentrations in individual fruitbodies in clusters of Cantharellus tubaeformis

    International Nuclear Information System (INIS)

    Nikolova, I.; Johanson, K.J.

    1999-01-01

    Fruitbodies of Cantharellus tubaeformis grown in clusters were collected from a normal Swedish coniferous forest. In the laboratory, individual fruitbodies were transferred into plastic vials and the 137 Cs activity concentrations were determined and expressed as Bq kg -1 fresh weight. After drying at 55 o , the 137 CS levels were recalculated and expressed as Bq kg -1 dry weight. Large variations of 137 Cs activity concentrations between individual fruitbodies within the clusters were observed. In 1995, the range in the 137 CS levels of individual fruitbodies in one cluster were from 9,194 to 164,811 and in another cluster from 2,338 to 38,377 Bq kg -1 . The mean values for these two clusters were 90,294 and 13,556 Bq kg -1 respectively. In 1998, the mean value for eight clusters showed a range from 26,373 to 67,281 Bq kg -1 . The largest variations between individual fruitbodies within a cluster were from 11,875 to 107,160 Bq kg -1 . Refs. 10 (author)

  5. Temporal variation in fish mercury concentrations within lakes from the western Aleutian Archipelago, Alaska.

    Directory of Open Access Journals (Sweden)

    Leah A Kenney

    Full Text Available We assessed temporal variation in mercury (Hg concentrations of threespine stickleback (Gasterosteus aculeatus from Agattu Island, Aleutian Archipelago, Alaska. Total Hg concentrations in whole-bodied stickleback were measured at two-week intervals from two sites in each of two lakes from June 1 to August 10, 2011 during the time period when lakes were ice-free. Across all sites and sampling events, stickleback Hg concentrations ranged from 0.37-1.07 µg/g dry weight (dw, with a mean (± SE of 0.55 ± 0.01 µg/g dw. Mean fish Hg concentrations declined by 9% during the study period, from 0.57 ± 0.01 µg/g dw in early June to 0.52 ± 0.01 µg/g dw in mid-August. Mean fish Hg concentrations were 6% higher in Loon Lake (0.56 ± 0.01 µg/g dw than in Lake 696 (0.53 ± 0.01 µg/g dw, and 4% higher in males (0.56 ± 0.01 µg/g dw than in females (0.54 ± 0.01 µg/g dw. Loon Lake was distinguished from Lake 696 by the presence of piscivorous waterbirds during the breeding season. Mercury concentrations in stickleback from Agattu Island were higher than would be expected for an area without known point sources of Hg pollution, and high enough to be of concern to the health of piscivorous wildlife.

  6. Temporal variation in fish mercury concentrations within lakes from the western Aleutian Archipelago, Alaska

    Science.gov (United States)

    Kenney, Leah A.; Eagles-Smith, Collin A.; Ackerman, Joshua T.; von Hippel, Frank A.

    2014-01-01

    We assessed temporal variation in mercury (Hg) concentrations of threespine stickleback (Gasterosteus aculeatus) from Agattu Island, Aleutian Archipelago, Alaska. Total Hg concentrations in whole-bodied stickleback were measured at two-week intervals from two sites in each of two lakes from June 1 to August 10, 2011 during the time period when lakes were ice-free. Across all sites and sampling events, stickleback Hg concentrations ranged from 0.37–1.07 µg/g dry weight (dw), with a mean (± SE) of 0.55±0.01 µg/g dw. Mean fish Hg concentrations declined by 9% during the study period, from 0.57±0.01 µg/g dw in early June to 0.52±0.01 µg/g dw in mid-August. Mean fish Hg concentrations were 6% higher in Loon Lake (0.56±0.01 µg/g dw) than in Lake 696 (0.53±0.01 µg/g dw), and 4% higher in males (0.56±0.01 µg/g dw) than in females (0.54±0.01 µg/g dw). Loon Lake was distinguished from Lake 696 by the presence of piscivorous waterbirds during the breeding season. Mercury concentrations in stickleback from Agattu Island were higher than would be expected for an area without known point sources of Hg pollution, and high enough to be of concern to the health of piscivorous wildlife.

  7. Seasonal variation in the composition and concentration of butyltin compounds in marine fish of Taiwan

    Energy Technology Data Exchange (ETDEWEB)

    Dong, C.D.; Chen, C.W.; Liu, L.L

    2004-10-01

    For the first time, strong evidence is presented to demonstrate that the accumulations of butyltin compounds (BTs) exhibit seasonal variations with respect to their compositions and concentrations in marine fishes. Measurements were made on the benthic ponyfish Leiogenathus splendens and lizardfish Trachinocephalus myops inhabiting the west coast of Taiwan. In the whole body samples of the ponyfish, BT concentrations ranged from 236 to 2501 ng/g wet wt, with those in winter considerably higher than in the other seasons (p<0.05). In a similar vein, proportions of mono- (MBT), di- (DBT) and tributyltin (TBT) differed significantly (p<0.001) depending upon the season, with TBT (75 and 50%) dominant in winter and spring and DBT (37 and 57%) and MBT (42 and 24%) dominant in summer and autumn, respectively. In the lizardfish, the concentrations of BTs were one to two orders of magnitude higher in the liver than in the muscle, i.e. 3058-11,473 vs. 36-159 ng/g wet wt, respectively. Concentrations of MBT, DBT and TBT in the muscle ranged, respectively, from 5 to 14, 8 to 35 and 23 to 110 ng/g wet wt, with the major compound being TBT (57-69%) in all seasons. However, in the liver, DBT concentrations, ranging from 992 to 7797 ng/g wet wt, differed seasonally with a descending order of autumn > summer > spring (p<0.05). Meanwhile, TBT (41%) was predominant in spring, whereas DBT (50 and 68%) was most heavily concentrated in summer and autumn (p<0.001). Seasonally mediated physiological changes, such as dilution due to growth and metabolic compensation, may play important roles in forming different BT accumulation patterns among seasons and organisms.

  8. Radiative effects of ozone on the climate of a Snowball Earth

    Directory of Open Access Journals (Sweden)

    J. Yang

    2012-12-01

    Full Text Available Some geochemical and geological evidence has been interpreted to suggest that the concentration of atmospheric oxygen was only 1–10 % of the present level in the time interval from 750 to 580 million years ago when several nearly global glaciations or Snowball Earth events occurred. This low concentration of oxygen would have been accompanied by a lower ozone concentration than exists at present. Since ozone is a greenhouse gas, this change in ozone concentration would alter surface temperature, and thereby could have an important influence on the climate of the Snowball Earth. Previous works that have focused either on initiation or deglaciation of the proposed Snowball Earth has not taken the radiative effects of ozone changes into account. We address this issue herein by performing a series of simulations using an atmospheric general circulation model with various ozone concentrations.

    Our simulation results demonstrate that, as ozone concentration is uniformly reduced from 100 % to 50 %, surface temperature decreases by approximately 0.8 K at the Equator, with the largest decreases located in the middle latitudes reaching as high as 2.5 K. When ozone concentration is reduced and its vertical and horizontal distribution is simultaneously modulated, surface temperature decreases by 0.4–1.0 K at the Equator and by 4–7 K in polar regions. These results here have uncertainties, depending on model parameterizations of cloud, surface snow albedo, and relevant feedback processes, while they are qualitatively consistent with radiative-convective model results that do not involve such parameterizations and feedbacks. These results suggest that ozone variations could have had a moderate impact on the climate during the Neoproterozoic glaciations.

  9. Measurements to understand the role of the sub Arctic environment on boundary layer ozone, gaseous mercury and bromine oxide concentrations

    Science.gov (United States)

    Netcheva, S.; Bottenheim, J.; Staebler, R.; Steffen, A.; Bobrowski, N.; Moores, J.

    2009-04-01

    Marine Boundary Layer spring time ozone (O3) and Gaseous Elemental Mercury (GEM) depletion episodes in Polar Regions and the role played by reactive halogen species have been studied for several years. Understanding of the photochemistry involved has improved significantly in the last few years, but many questions remain. The key in filling many gaps of information is in conducting systematic measurements over freezing and thawing surfaces of big water basins in Polar Regions where depletion episodes are thought to originate. Regardless of extensive research in the field, data sets collected over the ice are limited due to logistics and engineering challenges. The fast changing Arctic environment with its potential implications for climate change and human and ecosystem health demand urgent development of a predictive capability that could only be achieved by complete quantitative understanding of these phenomena. The Out On The Ice (OOTI) mini atmospheric chemistry laboratory was developed in 2004 specifically to permit collecting data at remote locations in an autonomous way. The system is battery powered, easily transported by snowmobile and quickly deployed at a target location. The equipment has undergone multiple engineering and instrumentation improvements. In its current version, it conducts fully automated measurements of O3, GEM and carbon dioxide (CO2) simultaneously at two levels: right above a surface of interest and at 2.5 meters. This is accomplished by utilizing two identical sets of instruments (2B for O3 and Gardis for GEM), or by continuous valve switching (CO2). A vertical profile of bromine oxide is determined by scanning the collecting optics of a Differential Optical Absorption Spectrometer through different elevation angles. Furthermore a full set of meteorological data is acquired in parallel with the chemical measurements in order to evaluate environmental and air mass transport contributions. We will present results from data collected

  10. Diurnal variation and reliability of the urine lactate concentration after maximal exercise.

    Science.gov (United States)

    Nikolaidis, Stefanos; Kosmidis, Ioannis; Sougioultzis, Michail; Kabasakalis, Athanasios; Mougios, Vassilis

    2018-01-01

    The postexercise urine lactate concentration is a novel valid exercise biomarker, which has exhibited satisfactory reliability in the morning hours under controlled water intake. The aim of the present study was to investigate the diurnal variation of the postexercise urine lactate concentration and its reliability in the afternoon hours. Thirty-two healthy children (11 boys and 21 girls) and 23 adults (13 men and 10 women) participated in the study. All participants performed two identical sessions of eight 25 m bouts of maximal freestyle swimming executed every 2 min with passive recovery in between. These sessions were performed in the morning and afternoon and were separated by 3-4 days. Adults performed an additional afternoon session that was also separated by 3-4 days. All swimmers drank 500 mL of water before and another 500 mL after each test. Capillary blood and urine samples were collected before and after each test for lactate determination. Urine creatinine, urine density and body water content were also measured. The intraclass correlation coefficient was used as a reliability index between the morning and afternoon tests, as well as between the afternoon test and retest. Swimming performance and body water content exhibited excellent reliability in both children and adults. The postexercise blood lactate concentration did not show diurnal variation, showing a good reliability between the morning and afternoon tests, as well as high reliability between the afternoon test and retest. The postexercise urine density and lactate concentration were affected by time of day. However, when lactate was normalized to creatinine, it exhibited excellent reliability in children and good-to-high reliability in adults. The postexercise urine lactate concentration showed high reliability between the afternoon test and retest, independent of creatinine normalization. The postexercise blood and urine lactate concentrations were significantly correlated in all

  11. Variation of molecular hydrogen tropospheric concentration over Southern Poland - results of the continuous chromatographic measurements.

    Science.gov (United States)

    Necki, J.; Chmura, L.

    2012-04-01

    process with precision better than 1ppb. But a temporary problems with UV lamp power supply module considerably hampers the research and adversely affect the reproducibility of the analysis. The results should be treated as a preliminary diagnosis of the diurnal and seasonal variation of the hydrogen concentration at the mountain site. The average short term variation of hydrogen concentrations does not exceed 50ppb and reveals the periodic nature except special situations when the concentration abruptly rises up by 150ppb and returns to an average of 480-520ppb. It is possible to observe the variations with larger time constant probably related with mezzo-scale circulation in atmosphere and slight seasonality in the level of hydrogen observed in autumn and in winter (with amplitude of 50ppb). Measurements carried out at Kasprowy Wierch were also used to balance the hydrogen for the city of Kraków. The work was partly financed from Polish national grant N N305 400939.

  12. Trimodal distribution of ozone and water vapor in the UT/LS during boreal summer

    Science.gov (United States)

    Dunkerton, T. J.

    2004-12-01

    The relation of ozone and water vapor in the upper troposphere and lower stratosphere (UT/LS) is strongly influenced by the off-equatorial Asian and North American monsoons in boreal summer. Both regions experience hydration, presumably as a result of deep convection. This behavior contrasts sharply with the apparent dehydrating influence of near-equatorial deep convection in boreal winter. There is also a striking difference in ozone between Asia and North America in boreal summer. Over Asia, ozone concentrations are low, evidently a result of ubiquitous deep convection and the vertical transport of ozone-poor air, while over North America, ozone concentrations are much higher. Since deep convection also occurs in the North American monsoon, it appears that the difference in ozone concentration between Asia and North America in boreal summer reflects a differing influence of the large-scale circulation in the two regions: specifically, (i) isolation of the Tibetan anticyclone versus (ii) the intrusion of filaments of ozone-rich air from the stratosphere over North America. During boreal summer, as in winter, near-equatorial concentrations of ozone and water vapor are low near the equator. The result of these geographical variations is a trimodal distribution of ozone and water-vapor correlation. Our talk reviews the observational evidence of this trimodal distribution and possible dynamical and microphysical causes, focusing primarily on the quality and possible sampling bias of satellite and aircraft measurements. A key issue is the ability of HALOE to sample areas of ubiquitous deep convection. Other issues include the vertical structure of tracer anomalies, isentropic stirring in the UT/LS, horizontal transport of biomass burning products lofted by deep convection, and connections to the moist phase of the tropical `tape recorder' signal in water vapor.

  13. Arsenic Species in Chicken Breast: Temporal Variations of Metabolites, Elimination Kinetics, and Residual Concentrations.

    Science.gov (United States)

    Liu, Qingqing; Peng, Hanyong; Lu, Xiufen; Zuidhof, Martin J; Li, Xing-Fang; Le, X Chris

    2016-08-01

    Chicken meat has the highest per capita consumption among all meat types in North America. The practice of feeding 3-nitro-4-hydroxyphenylarsonic acid (Roxarsone, Rox) to chickens lasted for more than 60 years. However, the fate of Rox and arsenic metabolites remaining in chicken are poorly understood. We aimed to determine the elimination of Rox and metabolites from chickens and quantify the remaining arsenic species in chicken meat, providing necessary information for meaningful exposure assessment. We have conducted a 35-day feeding experiment involving 1,600 chickens, of which half were control and the other half were fed a Rox-supplemented diet for the first 28 days and then a Rox-free diet for the final 7 days. We quantified the concentrations of individual arsenic species in the breast meat of 229 chickens. Rox, arsenobetaine, arsenite, monomethylarsonic acid, dimethylarsinic acid, and a new arsenic metabolite, were detected in breast meat from chickens fed Rox. The concentrations of arsenic species, except arsenobetaine, were significantly higher in the Rox-fed than in the control chickens. The half-lives of elimination of these arsenic species were 0.4-1 day. Seven days after termination of Rox feeding, the concentrations of arsenite (3.1 μg/kg), Rox (0.4 μg/kg), and a new arsenic metabolite (0.8 μg/kg) were significantly higher in the Rox-fed chickens than in the control. Feeding of Rox to chickens increased the concentrations of five arsenic species in breast meat. Although most arsenic species were excreted rapidly when the feeding of Rox stopped, arsenic species remaining in the Rox-fed chickens were higher than the background levels. Liu Q, Peng H, Lu X, Zuidhof MJ, Li XF, Le XC. 2016. Arsenic species in chicken breast: temporal variations of metabolites, elimination kinetics, and residual concentrations. Environ Health Perspect 124:1174-1181; http://dx.doi.org/10.1289/ehp.1510530.

  14. Indoor transient SOA formation from ozone + α-pinene reactions: Impacts of air exchange and initial product concentrations, and comparison to limonene ozonolysis

    Science.gov (United States)

    Youssefi, Somayeh; Waring, Michael S.

    2015-07-01

    The ozonolysis of reactive organic gases (ROG), e.g. terpenes, generates secondary organic aerosol (SOA) indoors. The SOA formation strength of such reactions is parameterized by the aerosol mass fraction (AMF), a.k.a. SOA yield, which is the mass ratio of generated SOA to oxidized ROG. AMFs vary in magnitude both among and for individual ROGs. Here, we quantified dynamic SOA formation from the ozonolysis of α-pinene with 'transient AMFs,' which describe SOA formation due to pulse emission of a ROG in an indoor space with air exchange, as is common when consumer products are intermittently used in ventilated buildings. We performed 19 experiments at low, moderate, and high (0.30, 0.52, and 0.94 h-1, respectively) air exchange rates (AER) at varying concentrations of initial reactants. Transient AMFs as a function of peak SOA concentrations ranged from 0.071 to 0.25, and they tended to increase as the AER and product of the initial reactant concentrations increased. Compared to our similar research on limonene ozonolysis (Youssefi and Waring, 2014), for which formation strength was driven by secondary ozone reactions, the AER impact for α-pinene was opposite in direction and weaker, while the initial reactant product impact was in the same direction but stronger for α-pinene than for limonene. Linear fits of AMFs for α-pinene ozonolysis as a function of the AER and initial reactant concentrations are provided so that future indoor models can predict SOA formation strength.

  15. Variation of indoor radon concentration and ambient dose equivalent rate in different outdoor and indoor environments

    Energy Technology Data Exchange (ETDEWEB)

    Stojanovska, Zdenka; Janevik, Emilija; Taleski, Vaso [Goce Delcev University, Faculty of Medical Sciences, Stip (Macedonia, The Former Yugoslav Republic of); Boev, Blazo [Goce Delcev University, Faculty of Natural and Technical Sciences, Stip (Macedonia, The Former Yugoslav Republic of); Zunic, Zora S. [University of Belgrade, Institute of Nuclear Sciences ' ' Vinca' ' , Belgrade (Serbia); Ivanova, Kremena; Tsenova, Martina [National Center of Radiobiology and Radiation Protection, Sofia (Bulgaria); Ristova, Mimoza [University in Ss. Cyril and Methodius, Faculty of Natural Sciences and Mathematic, Institute of Physics, Skopje (Macedonia, The Former Yugoslav Republic of); Ajka, Sorsa [Croatian Geological Survey, Zagreb (Croatia); Bossew, Peter [German Federal Office for Radiation Protection, Berlin (Germany)

    2016-05-15

    Subject of this study is an investigation of the variations of indoor radon concentration and ambient dose equivalent rate in outdoor and indoor environments of 40 dwellings, 31 elementary schools and five kindergartens. The buildings are located in three municipalities of two, geologically different, areas of the Republic of Macedonia. Indoor radon concentrations were measured by nuclear track detectors, deployed in the most occupied room of the building, between June 2013 and May 2014. During the deploying campaign, indoor and outdoor ambient dose equivalent rates were measured simultaneously at the same location. It appeared that the measured values varied from 22 to 990 Bq/m{sup 3} for indoor radon concentrations, from 50 to 195 nSv/h for outdoor ambient dose equivalent rates, and from 38 to 184 nSv/h for indoor ambient dose equivalent rates. The geometric mean value of indoor to outdoor ambient dose equivalent rates was found to be 0.88, i.e. the outdoor ambient dose equivalent rates were on average higher than the indoor ambient dose equivalent rates. All measured can reasonably well be described by log-normal distributions. A detailed statistical analysis of factors which influence the measured quantities is reported. (orig.)

  16. Distribution and seasonal variation of concentrations of particulate carbohydrates and uronic acids in the northern Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Khodse, V.B.; Fernandes, L.; Gopalakrishna, V.V.; Bhosle, N.B.; Fernandes, V.; Matondkar, S.G.P.; Bhushan, R.

    particulate carbohydrate (TPCHO), total particulate uronic acid (TPURA) and total particulate neutral carbohydrate (TPNCHO) concentrations and composition. Strong spatial, temporal and depth related variations were evident in the distribution...

  17. Trend analysis of urban NO2 concentrations and the importance of direct NO2 emissions versus ozone/NOx equilibrium

    NARCIS (Netherlands)

    Keuken, M.; Roemer, M.; Elshout, S. van den

    2009-01-01

    The annual air quality standard of NO2 is often exceeded in urban areas near heavy traffic locations. Despite significant decrease of NOx emissions in 1986-2005 in the industrial and harbour area near Rotterdam, NO2 concentrations at the urban background remain at the same level since the end of the

  18. Suppression of local haze variations in MERIS images over turbid coastal waters for retrieval of suspended sediment concentration

    NARCIS (Netherlands)

    Shen, F.; Verhoef, W.

    2010-01-01

    Atmospheric correction over turbid waters can be problematic if atmospheric haze is spatially variable. In this case the retrieval of water quality is hampered by the fact that haze variations could be partly mistaken for variations in suspended sediment concentration (SSC). In this study we propose

  19. Ozone flux of an urban orange grove: multiple scaled measurements and model comparisons

    Science.gov (United States)

    Alstad, K. P.; Grulke, N. E.; Jenerette, D. G.; Schilling, S.; Marrett, K.

    2009-12-01

    There is significant uncertainty about the ozone sink properties of the phytosphere due to a complexity of interactions and feedbacks with biotic and abiotic factors. Improved understanding of the controls on ozone fluxes is critical to estimating and regulating the total ozone budget. Ozone exchanges of an orange orchard within the city of Riverside, CA were examined using a multiple-scaled approach. We access the carbon, water, and energy budgets at the stand- to leaf- level to elucidate the mechanisms controlling the variability in ozone fluxes of this agro-ecosystem. The two initial goals of the study were 1. To consider variations and controls on the ozone fluxes within the canopy; and, 2. To examine different modeling and scaling approaches for totaling the ozone fluxes of this orchard. Current understanding of the total ozone flux between the atmosphere near ground and the phytosphere (F-total) include consideration of a fraction which is absorbed by vegetation through stomatal uptake (F-absorb), and fractional components of deposition on external, non-stomatal, surfaces of the vegetation (F-external) and soil (F-soil). Multiplicative stomatal-conductance models have been commonly used to estimate F-absorb, since this flux cannot be measured directly. We approach F-absorb estimates for this orange orchard using chamber measurement of leaf stomatal-conductance, as well as non-chamber sap-conductance collected on branches of varied aspect and sun/shade conditions within the canopy. We use two approaches to measure the F-total of this stand. Gradient flux profiles were measured using slow-response ozone sensors collecting within and above the canopy (4.6 m), and at the top of the tower (8.5 m). In addition, an eddy-covariance system fitted with a high-frequency chemiluminescence ozone system will be deployed (8.5 m). Preliminary ozone gradient flux profiles demonstrate a substantial ozone sink strength of this orchard, with diurnal concentration differentials

  20. 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.

  1. Diurnal variation of the serum leptin concentration in patients with anorexia nervosa

    DEFF Research Database (Denmark)

    Støving, R K; Vinten, J; Handberg, A

    1998-01-01

    , however, this has been reported to be absent in normal weighted amenorrheic athletes. Anorexia nervosa is associated with multiple endocrine abnormalities. Hypothalamic amenorrhoea often precedes the weight loss and may persist after weight recovery. We hypothesized that leptin could be involved...... in the regulation of eating behaviour and gonadal function in anorexia nervosa. DESIGN: We measured the concentration of leptin in serum samples taken after an overnight fast in 18 female anorexia nervosa patients and 11 controls. To study diurnal variation, eight patients and 11 controls were hospitalized for 24 h...... and had a standardized diet at regular times. Seven blood samples were obtained at 4 h intervals from each subject. PATIENTS: The patients fulfilled the DSM-IV criteria for anorexia nervosa. The mean body mass index for the patients was 14.2 +/- 2.3 kg/m2 and for controls 20.3 +/- 1.7 kg/m2. RESULTS...

  2. Effect of concentration variation in graphene oxide (GO) membranes for water flux optimization

    Science.gov (United States)

    Kumar, Shani; Garg, Amit; Chowdhuri, Arijit

    2018-05-01

    Graphene oxide, sister material of Graphene has generated tremendous research interest in fields of energy storage, catalyst material, adsorbent material for heavy metals and dyes, green energy production, drug delivery agent, a gas sensing material as well as in membrane based water purification and desalination systems1-3 etc. In this paper, we are reporting the effect of concentration variation in GO membranes on water flux. GO has been synthesized by Hummer's method with related characterizations like XRD, Raman, SEM and FTIR carried out. GO membranes have been developed using pressure assisted filtration assembly (Water Vac-100) over Cellulose Acetate membrane support (47 mm dia. and 0.45 µm pore size), Millipore.

  3. Determination of the variation of mercury isotope concentration based on spectral-phase effects

    International Nuclear Information System (INIS)

    Ganeev, A.A.; Man', D.D.; Turkin, Yu.I.

    1988-01-01

    A method of isotopic atomic-absorption analysis, based on spectral-phase effects in which there is no need to use several sources of radiation with pure isotopes of the analyte element, was developed. The method made it possible to simplify the analysis and to determine the variation of the concentration of mercury isotopes from one deposit to another with an accuracy several times higher that of traditional methods of spectral isotopic analysis. The method was tested on mercury 198 and mercury 202. The isotopic analyzer is diagramed and described. The mechanism of spectral-phase effects was determined by the difference in effective photon lifetimes, corresponding to different components of the hyperfine structure of the resonance line of mercury at 254 nm

  4. Age and sex variation in serum albumin concentration: an observational study.

    Science.gov (United States)

    Weaving, Gary; Batstone, Gifford F; Jones, Richard G

    2016-01-01

    In the UK, a common reference interval for serum albumin is widely used irrespective of age or sex. Implicit in this is that laboratories produce analytically similar results. This paper challenges the validity of this approach. A three-week collection of results sent to all primary care centres in England has been analysed by age, sex and laboratory. In all, 1,079,193 serum albumin reports were included in this analysis. The mean population serum albumin concentration increases to peak at around age 20 years and then decreases with increasing age. Values in females decrease more rapidly but become close to male values at 60 years. The variation between laboratories was large and potentially clinically significant. Reference intervals for serum albumin should be stratified by age and sex. Until there is greater methodological standardization, laboratories should determine their own reference intervals and not accept a single consensus reference interval. © The Author(s) 2015.

  5. Seasonal variations in chromium concentration in urban atmospheric aerosol in the city of Radom

    Directory of Open Access Journals (Sweden)

    Molik Artur

    2018-01-01

    Full Text Available This paper presents seasonal variations in the occurrence of chromium in urban particulate matter (PM. Radom is an interesting area for this type of research due to its typical antiquated heating infrastructure. PM samples of two particulate fractions PM2.5 (particulates ≤ 2.5 µm and PM10 (particulates ≤ 10 µm were collected using a Copley cascade impactor Hi-Flow MOUDI Model 130. Chromium was determined in the samples using the GF-AAS technique. The concentration of chromium in PM2.5 was in the range of 0.38 to 3.2 ng/m3, whereas in PM10 it ranged from 0.43 to 4.1 ng/m3.

  6. Diurnal variations of airborne fungal spores concentration in the town and rural area

    Directory of Open Access Journals (Sweden)

    Idalia Kasprzyk

    2012-12-01

    Full Text Available Airborne fungal spores were monitored in 2001-2002 in Rzeszów (town and its neighborhood. The aim of investigations was to ascertain if there were differences in diurnal variations of airborne fungal spores concentration between town and rural area. The sampling was carried out using volumetric method. Traps were located at the same heights - app. 12 m. Airborne spores were sampled continuously. Microscopical slides were prepared for each day. Analysis was carried out on one longitudinal band of 48 mm long divided into 24 segments corresponding following hours of day. The results were expressed as mean number of fungal spores per cubic meter per 24 hours. For this survey, five geni of allergenic fungi were selected: Alternaria, Botrytis, Cladosporium, Epicoccum, Ganoderma. The concentrations of their airborne spores were high or very high. It was calculated theoretical day, where the hourly count was the percentage mean of number of spores at that time every chosen day without rainfall from 2001 and 2001 years. The diurnal periodicity of Alternaria, Cladosporium, Epicoccum and Ganoderma showed one peak, while Botrytis two. Anamorphic spores peaked in the afternoon, while their minima occurred in the morning. The highest concentrations of Ganoderma basidiospores were at down or at night, but minima during the day. There were no clear differences in the peak values between two studied sites. The results indicate that maximum concentrations of all spores generally occurred a few hour earlier in the rural area than in the town. Probably, in the rural area airborne spores came from many local sources and their diurnal periodicity reflected rhythm of spore liberation. Towns are characterized by specific microclimate with higher temperature and wind blowing to the centre. In Rzeszów fungal spores could be transported outside and carried out by wind from distant sources. This study showed, among others, that habitat conditions are an important factors

  7. The variation of particle gas-borne concentration with time in a gas cooled reactor

    Energy Technology Data Exchange (ETDEWEB)

    Reed, J; Hall, D; Reeks, M W [Central Electricity Generating Board, Berkeley Nuclear Laboratories (United Kingdom)

    1985-07-01

    If volatile fission products are released from fuel during a reactor fault, a significant fraction could become attached to small particles also present in the coolant. In such circumstances the retention of those particles by the reactor circuit will limit the level of gas-borne particle concentration and hence be important in reducing the potential release of fission product activity to the atmosphere. Clearly the retention of particles will be influenced by both the deposition and resuspension of particles from surfaces exposed to the coolant flow. In this paper we consider deposition and resuspension but pay particular attention to the role of resuspension, which in the past has been given little consideration. A recently developed model for the resuspension of small particles by a turbulent flow is outlined. Traditionally, resuspension has been interpreted as a force balance between the aerodynamic removal forces and the surface adhesive forces. In contrast, this new approach embodies an energy balance criterion for particle resuspension. Furthermore, the stochastic nature of this new model has shown that resuspension can be sub-divided into two regimes: (i) initial resuspension (resuspension occurring in times less than a second) which reduces the net deposition of particles to a surface; and (ii) longer term resuspension (resuspension after 1 second) which determines the asymptotic decay of particle gas-borne concentration. It is seen that the asymptotic decay varies almost inversely as the decay time. Force balance models are unsuccessful in accounting for the experimentally observed longer term resuspension. We show that a Volterra integro-differential equation best describes the variation of particle gas-borne concentration with time in a recirculating gas flow such as a gas cooled reactor. It is seen that the longer term resuspension has a major influence in the final decay of particle concentration. (author)

  8. The variation of particle gas-borne concentration with time in a gas cooled reactor

    International Nuclear Information System (INIS)

    Reed, J.; Hall, D.; Reeks, M.W.

    1985-01-01

    If volatile fission products are released from fuel during a reactor fault, a significant fraction could become attached to small particles also present in the coolant. In such circumstances the retention of those particles by the reactor circuit will limit the level of gas-borne particle concentration and hence be important in reducing the potential release of fission product activity to the atmosphere. Clearly the retention of particles will be influenced by both the deposition and resuspension of particles from surfaces exposed to the coolant flow. In this paper we consider deposition and resuspension but pay particular attention to the role of resuspension, which in the past has been given little consideration. A recently developed model for the resuspension of small particles by a turbulent flow is outlined. Traditionally, resuspension has been interpreted as a force balance between the aerodynamic removal forces and the surface adhesive forces. In contrast, this new approach embodies an energy balance criterion for particle resuspension. Furthermore, the stochastic nature of this new model has shown that resuspension can be sub-divided into two regimes: (i) initial resuspension (resuspension occurring in times less than a second) which reduces the net deposition of particles to a surface; and (ii) longer term resuspension (resuspension after 1 second) which determines the asymptotic decay of particle gas-borne concentration. It is seen that the asymptotic decay varies almost inversely as the decay time. Force balance models are unsuccessful in accounting for the experimentally observed longer term resuspension. We show that a Volterra integro-differential equation best describes the variation of particle gas-borne concentration with time in a recirculating gas flow such as a gas cooled reactor. It is seen that the longer term resuspension has a major influence in the final decay of particle concentration. (author)

  9. Large variation in the Rubisco kinetics of diatoms reveals diversity among their carbon-concentrating mechanisms

    Science.gov (United States)

    Young, Jodi N.; Heureux, Ana M.C.; Sharwood, Robert E.; Rickaby, Rosalind E.M.; Morel, François M.M.; Whitney, Spencer M.

    2016-01-01

    While marine phytoplankton rival plants in their contribution to global primary productivity, our understanding of their photosynthesis remains rudimentary. In particular, the kinetic diversity of the CO2-fixing enzyme, Rubisco, in phytoplankton remains unknown. Here we quantify the maximum rates of carboxylation (k cat c), oxygenation (k cat o), Michaelis constants (K m) for CO2 (K C) and O2 (K O), and specificity for CO2 over O2 (SC/O) for Form I Rubisco from 11 diatom species. Diatom Rubisco shows greater variation in K C (23–68 µM), SC/O (57–116mol mol−1), and K O (413–2032 µM) relative to plant and algal Rubisco. The broad range of K C values mostly exceed those of C4 plant Rubisco, suggesting that the strength of the carbon-concentrating mechanism (CCM) in diatoms is more diverse, and more effective than previously predicted. The measured k cat c for each diatom Rubisco showed less variation (2.1–3.7s−1), thus averting the canonical trade-off typically observed between K C and k cat c for plant Form I Rubisco. Uniquely, a negative relationship between K C and cellular Rubisco content was found, suggesting variation among diatom species in how they allocate their limited cellular resources between Rubisco synthesis and their CCM. The activation status of Rubisco in each diatom was low, indicating a requirement for Rubisco activase. This work highlights the need to better understand the correlative natural diversity between the Rubisco kinetics and CCM of diatoms and the underpinning mechanistic differences in catalytic chemistry among the Form I Rubisco superfamily. PMID:27129950

  10. 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

  11. Detection of atmospheric tritium by scintillation. Variations in its concentration in France; Detection du tritium atmospherique par scintillation. Evolution de sa concentration en France

    Energy Technology Data Exchange (ETDEWEB)

    Bibron, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-06-01

    The tritium released into the atmosphere as a result of the explosion of thermonuclear devices is a useful radioactive tracer for the study of certain geophysical problems. The low concentrations found however call for the use of extremely sensitive detectors. Two detection methods using liquid scintillators are described. In the first method, the sample is introduced into the scintillator in liquid form, after prior concentration of the tritium by electrolysis. In the second method the tritium is incorporated into the scintillator solvent molecule by chemical synthesis. In the last part of the report are examined the variations in the tritium concentration in rain-water and of the free hydrogen in the air in France. A discussion is then made of the seasonal variations in the case of rain-water and these are compared to the variations in the strontium-90 concentrations. (author) [French] Le tritium introduit dans l'atmosphere par les explosions d'armes thermonucleaires est un traceur radioactif Interessant pour l'etude de certains problemes de geophysique. Les faibles concentrations rencontrees obligent toutefois a utiliser des detecteurs extremement sensibles. On decrit deux methodes de detection utilisant des scintillateurs liquides. Dans la premiere methode, l'echantillon est introduit dans le scintillateur, sous forme aqueuse, apres une concentration prealable du tritium par electrolyse. Dans la seconde methode, le tritium est incorpore a la molecule du solvant du scintillateur par synthese chimique. Dans la derniere partie du rapport, on examine l'evolution de la concentration du tritium dans les eaux de precipitation et l'hydrogene libre de l'air en France. On discute ensuite les variations saisonnieres dans le cas des eaux de precipitation et on les compare aux variations du strontium 90. (auteur)

  12. Detection of atmospheric tritium by scintillation. Variations in its concentration in France; Detection du tritium atmospherique par scintillation. Evolution de sa concentration en France

    Energy Technology Data Exchange (ETDEWEB)

    Bibron, R. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-06-01

    The tritium released into the atmosphere as a result of the explosion of thermonuclear devices is a useful radioactive tracer for the study of certain geophysical problems. The low concentrations found however call for the use of extremely sensitive detectors. Two detection methods using liquid scintillators are described. In the first method, the sample is introduced into the scintillator in liquid form, after prior concentration of the tritium by electrolysis. In the second method the tritium is incorporated into the scintillator solvent molecule by chemical synthesis. In the last part of the report are examined the variations in the tritium concentration in rain-water and of the free hydrogen in the air in France. A discussion is then made of the seasonal variations in the case of rain-water and these are compared to the variations in the strontium-90 concentrations. (author) [French] Le tritium introduit dans l'atmosphere par les explosions d'armes thermonucleaires est un traceur radioactif Interessant pour l'etude de certains problemes de geophysique. Les faibles concentrations rencontrees obligent toutefois a utiliser des detecteurs extremement sensibles. On decrit deux methodes de detection utilisant des scintillateurs liquides. Dans la premiere methode, l'echantillon est introduit dans le scintillateur, sous forme aqueuse, apres une concentration prealable du tritium par electrolyse. Dans la seconde methode, le tritium est incorpore a la molecule du solvant du scintillateur par synthese chimique. Dans la derniere partie du rapport, on examine l'evolution de la concentration du tritium dans les eaux de precipitation et l'hydrogene libre de l'air en France. On discute ensuite les variations saisonnieres dans le cas des eaux de precipitation et on les compare aux variations du strontium 90. (auteur)

  13. A vegetation control on seasonal variations in global atmospheric mercury concentrations

    Science.gov (United States)

    Jiskra, Martin; Sonke, Jeroen E.; Obrist, Daniel; Bieser, Johannes; Ebinghaus, Ralf; Myhre, Cathrine Lund; Pfaffhuber, Katrine Aspmo; Wängberg, Ingvar; Kyllönen, Katriina; Worthy, Doug; Martin, Lynwill G.; Labuschagne, Casper; Mkololo, Thumeka; Ramonet, Michel; Magand, Olivier; Dommergue, Aurélien

    2018-04-01

    Anthropogenic mercury emissions are transported through the atmosphere as gaseous elemental mercury (Hg(0)) before they are deposited to Earth's surface. Strong seasonality in atmospheric Hg(0) concentrations in the Northern Hemisphere has been explained by two factors: anthropogenic Hg(0) emissions are thought to peak in winter due to higher energy consumption, and atmospheric oxidation rates of Hg(0) are faster in summer. Oxidation-driven Hg(0) seasonality should be equally pronounced in the Southern Hemisphere, which is inconsistent with observations of constant year-round Hg(0) levels. Here, we assess the role of Hg(0) uptake by vegetation as an alternative mechanism for driving Hg(0) seasonality. We find that at terrestrial sites in the Northern Hemisphere, Hg(0) co-varies with CO2, which is known to exhibit a minimum in summer when CO2 is assimilated by vegetation. The amplitude of seasonal oscillations in the atmospheric Hg(0) concentration increases with latitude and is larger at inland terrestrial sites than coastal sites. Using satellite data, we find that the photosynthetic activity of vegetation correlates with Hg(0) levels at individual sites and across continents. We suggest that terrestrial vegetation acts as a global Hg(0) pump, which can contribute to seasonal variations of atmospheric Hg(0), and that decreasing Hg(0) levels in the Northern Hemisphere over the past 20 years can be partly attributed to increased terrestrial net primary production.

  14. Variation of ascorbic acid concentration in fruits of cultivated and wild apples.

    Science.gov (United States)

    Fang, Ting; Zhen, Qiaoling; Liao, Liao; Owiti, Albert; Zhao, Li; Korban, Schuyler S; Han, Yuepeng

    2017-06-15

    Ascorbic acid (AsA) content in mature fruits of 457 apple accessions were measured, and a great variation in AsA concentration was detected. Wild fruits showed significantly higher level of AsA than cultivated fruits. Fruit AsA content was positively correlated with malic acid content, but negatively correlated with fruit weight and soluble solid content. Thus, the difference in AsA content between the wild and cultivated fruits could be attributed to an indirect consequence of human selection for larger fruit size, less acidity, and increased sweetness during apple domestication. Additionally, AsA concentration was extremely high in fruit at the juvenile stage, but dramatically decreased at the expanding and mature stages. The expression levels of three genes controlling AsA accumulation, MdGGP1, MdDHAR3-3, and MdNAT7-2, were significantly negatively correlated with AsA contents in fruits, suggesting a feedback regulation mechanism in AsA-related gene expression. Our results could be helpful for future apple breeding. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. 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.

  16. 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

  17. 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.

  18. Impacts of ozone air pollution and temperature extremes on crop yields: Spatial variability, adaptation and implications for future food security

    Science.gov (United States)

    Tai, Amos P. K.; Val Martin, Maria

    2017-11-01

    Ozone air pollution and climate change pose major threats to global crop production, with ramifications for future food security. Previous studies of ozone and warming impacts on crops typically do not account for the strong ozone-temperature correlation when interpreting crop-ozone or crop-temperature relationships, or the spatial variability of crop-to-ozone sensitivity arising from varietal and environmental differences, leading to potential biases in their estimated crop losses. Here we develop an empirical model, called the partial derivative-linear regression (PDLR) model, to estimate the spatial variations in the sensitivities of wheat, maize and soybean yields to ozone exposures and temperature extremes in the US and Europe using a composite of multidecadal datasets, fully correcting for ozone-temperature covariation. We find generally larger and more spatially varying sensitivities of all three crops to ozone exposures than are implied by experimentally derived concentration-response functions used in most previous studies. Stronger ozone tolerance is found in regions with high ozone levels and high consumptive crop water use, reflecting the existence of spatial adaptation and effect of water constraints. The spatially varying sensitivities to temperature extremes also indicate stronger heat tolerance in crops grown in warmer regions. The spatial adaptation of crops to ozone and temperature we find can serve as a surrogate for future adaptation. Using the PDLR-derived sensitivities and 2000-2050 ozone and temperature projections by the Community Earth System Model, we estimate that future warming and unmitigated ozone pollution can combine to cause an average decline in US wheat, maize and soybean production by 13%, 43% and 28%, respectively, and a smaller decline for European crops. Aggressive ozone regulation is shown to offset such decline to various extents, especially for wheat. Our findings demonstrate the importance of considering ozone regulation

  19. Ozone Pollution

    Science.gov (United States)

    Known as tropospheric or ground-level ozone, this gas is harmful to human heath and the environment. Since it forms from emissions of volatile organic compounds (VOCs) and nitrogen oxides (NOx), these pollutants are regulated under air quality standards.

  20. 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

  1. Variations of leaf N and P concentrations in shrubland biomes across northern China: phylogeny, climate, and soil

    Science.gov (United States)

    Yang, Xian; Chi, Xiulian; Ji, Chengjun; Liu, Hongyan; Ma, Wenhong; Mohhammat, Anwar; Shi, Zhaoyong; Wang, Xiangping; Yu, Shunli; Yue, Ming; Tang, Zhiyao

    2016-08-01

    Concentrations of leaf nitrogen (N) and phosphorus (P) are two key traits of plants for ecosystem functioning and dynamics. Foliar stoichiometry varies remarkably among life forms. However, previous studies have focused on the stoichiometric patterns of trees and grasses, leaving a significant knowledge gap for shrubs. In this study, we explored the intraspecific and interspecific variations of leaf N and P concentrations in response to the changes in climate, soil property, and evolutionary history. We analysed 1486 samples composed of 163 shrub species from 361 shrubland sites in northern China encompassing 46.1° (86.7-132.8° E) in longitude and 19.8° (32.6-52.4° N) in latitude. Leaf N concentrations decreased with precipitation, while leaf P concentrations decreased with temperature and increased with precipitation and soil total P concentrations. Both leaf N and P concentrations were phylogenetically conserved, but leaf P concentrations were less conserved than leaf N concentrations. At the community level, climate explained more interspecific variation of leaf nutrient concentrations, while soil nutrients explained most of the intraspecific variation. These results suggested that leaf N and P concentrations responded to climate, soil, and phylogeny in different ways. Climate influenced the community chemical traits through the shift in species composition, whereas soil directly influenced the community chemical traits. New patterns were discovered using our observations on specific regions and vegetation types, which improved our knowledge of broad biogeographic patterns of leaf chemical traits.

  2. Spring leaf flush in aspen (Populus tremuloides) clones is altered by long-term growth at elevated carbon dioxide and elevated ozone concentration

    International Nuclear Information System (INIS)

    McGrath, Justin M.; Karnosky, David F.; Ainsworth, Elizabeth A.

    2010-01-01

    Early spring leaf out is important to the success of deciduous trees competing for light and space in dense forest plantation canopies. In this study, we investigated spring leaf flush and how long-term growth at elevated carbon dioxide concentration ([CO 2 ]) and elevated ozone concentration ([O 3 ]) altered leaf area index development in a closed Populus tremuloides (aspen) canopy. This work was done at the Aspen FACE experiment where aspen clones have been grown since 1997 in conditions simulating the [CO 2 ] and [O 3 ] predicted for ∼2050. The responses of two clones were compared during the first month of spring leaf out when CO 2 fumigation had begun, but O 3 fumigation had not. Trees in elevated [CO 2 ] plots showed a stimulation of leaf area index (36%), while trees in elevated [O 3 ] plots had lower leaf area index (-20%). While individual leaf area was not significantly affected by elevated [CO 2 ], the photosynthetic operating efficiency of aspen leaves was significantly improved (51%). There were no significant differences in the way that the two aspen clones responded to elevated [CO 2 ]; however, the two clones responded differently to long-term growth at elevated [O 3 ]. The O 3 -sensitive clone, 42E, had reduced individual leaf area when grown at elevated [O 3 ] (-32%), while the tolerant clone, 216, had larger mature leaf area at elevated [O 3 ] (46%). These results indicate a clear difference between the two clones in their long-term response to elevated [O 3 ], which could affect competition between the clones, and result in altered genotypic composition in future atmospheric conditions. - Spring leaf flush is stimulated by elevated [CO 2 ] and suppressed by elevated [O 3 ] in aspen (Populus tremuloides).

  3. [Effects of elevated ozone on Pinus armandii growth: a simulation study with open-top chamber].

    Science.gov (United States)

    Liu, Chang-Fu; Liu, Chen; He, Xing-Yuan; Ruan, Ya-Nan; Xu, Sheng; Chen, Zhen-Ju; Peng, Jun-Jie; Li, Teng

    2013-10-01

    By using open-top chamber (OTC) and the techniques of dendrochronology, this paper studied the growth of Pinus armandii under elevated ozone, and explored the evolution dynamics and adaptation mechanisms of typical forest ecosystems to ozone enrichment. Elevated ozone inhibited the stem growth of P. armandii significantly, with the annual growth of the stem length and diameter reduced by 35.0% and 12.9%, respectively. The annual growth of tree-ring width and the annual ring cells number decreased by 11.5% and 54.1%, respectively, but no significant change was observed in the diameter of tracheid. At regional scale, the fluctuation of ozone concentration showed significant correlation with the variation of local vegetation growth (NDVI).

  4. Large-scale spatial variation in mercury concentrations in cattle in NW Spain

    International Nuclear Information System (INIS)

    Lopez Alonso, M.; Benedito, J.L.; Miranda, M.; Fernandez, J.A.; Castillo, C.; Hernandez, J.; Shore, R.F.

    2003-01-01

    This study quantifies the spatial scale over which major point and diffuse sources of anthropogenic mercury emission affect mercury accumulation by cattle in northwest Spain. - Mercury (Hg) is a highly toxic environmental contaminant and man-made emissions account for between a quarter and a third of total atmospheric levels. Point discharges, particularly coal-burning power stations, are major sources of atmospheric Hg and can result in marked spatial variation in mercury deposition and subsequent uptake by biota. The aims of this study were to quantify the extent to which major point and diffuse sources of atmospheric Hg emissions affected accumulation of Hg by biota throughout Galicia and Asturias, two of the major regions in northwest Spain. We did this by relating renal Hg concentrations in locally reared cattle (n=284) to the proximity of animals to point and diffuse sources of Hg emissions. Mercury residues in calf kidneys ranged between non-detected and 89.4 μg/kg wet weight. Point discharges from coal-fired power plants in Galicia had the most dominant impact on Hg accumulation by calves in Galicia, affecting animals throughout the region and explaining some two-thirds of the variation in renal residues between animals located directly downwind from the plants. The effects of more diffuse emission sources on Hg accumulation in calves were not distinguishable in Galicia but were detected in cattle from neighbouring Asturias. The impact of both point and diffuse sources in elevating environmental levels of bioavailable Hg and subsequent accumulation by cattle extended to approximately 140-200 km downwind from source

  5. Measuring variation of indoor radon concentration using bare nuclear tracks detectors, scintillation counters and surface barrier detectors

    International Nuclear Information System (INIS)

    Ishak, I.; Mahat, R.H.; Amin, Y.M.

    1996-01-01

    Bare LRI 15 nuclear track detectors , scintillators counter and surface barrier detectors were used to measured the indoor radon concentration in various location within two rooms. Spatial variation of the radon concentration is caused by positioning of the door, windows, furniture, cracks in the building and also distances from floor, wall and ceiling. It is found that the change in temperature are causing radon concentration to increase at certain time of the day

  6. Ozone and radon at Cape Grim: A study of their interdependence

    International Nuclear Information System (INIS)

    Zahorowski, W.; Galbally, I.E.; Meyer, C.P.

    1996-01-01

    A discussion of the ozone and radon variations at Cape Grim, Tasmania, and their interdependence is presented. The use of radon concentration as a criterion for baseline conditions ( - 3) results in a baseline data set that has a smaller range of concentrations within each month than that obtained using wind speed and direction as baseline criteria. The passage of cold fronts at Cape Grim is associated with a change in air flow from the continent to the Southern Ocean. Comparison of radon, wind direction and ozone during these events indicates that continental air continues arriving at Cape Grim for several hours after passage of the front and the establishment of the air flow from the baseline sector. This confirms that use of the speed and direction is not necessarily a good method of defining baseline conditions for ozone. When air comes to Cape Grim form over the Tasmanian land surface during those times of the year when (due to solar radiation and temperature) the probability of ozone production is low, the ozone and radon concentrations observed are negatively correlated. A simple model of ozone destruction at the Earth's surface and radon emission from the surface quantitatively describes these observations. (author). 1 tab., 5 figs., 6 refs

  7. Possible causes of variation in acrylamide concentration in French fries prepared in food service establishments: an observational study.

    Science.gov (United States)

    Sanny, M; Jinap, S; Bakker, E J; van Boekel, M A J S; Luning, P A

    2012-05-01

    Acrylamide is a probable human carcinogen, and its presence in a range of fried and oven-cooked foods has raised considerable health concern world-wide. Dietary intake studies observed significant variations in acrylamide concentrations, which complicate risk assessment and the establishment of effective control measures. The objective of this study was to obtain an insight into the actual variation in acrylamide concentrations in French fries prepared under typical conditions in a food service establishment (FSE). Besides acrylamide, frying time, frying temperature, and reducing sugars were measured and the actual practices at receiving, thawing and frying during French fries preparation were observed and recorded. The variation in the actual frying temperature contributed most to the variation in acrylamide concentrations, followed by the variation in actual frying time; no obvious effect of reducing sugars was found. The lack of standardised control of frying temperature and frying time (due to inadequate frying equipment) and the variable practices of food handlers seem to contribute most to the large variation and high acrylamide concentrations in French fries prepared in a restaurant type of FSE as compared to chain fast-food services, and institutional caterers. The obtained insights in this study can be used to develop dedicated control measures in FSE, which may contribute to a sustainable reduction in the acrylamide intake. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. 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...

  9. Temporal variation of tritium concentration in tree-ring cellulose over the past 50 years

    International Nuclear Information System (INIS)

    Yamada, Y.; Yasuike, K.; Komura, K.

    2004-01-01

    Concentration of organically-bound tritium in the tree-ring cellulose of a pine tree grown in Shika-machi, Ishikawa prefecture, Japan (37.1degN, 136.5degE), was measured during the ring-years from 1949 to 1999. The results were compared with those of a pine tree grown in Tatsunokuchi-machi, Ishikawa prefecture, Japan (36.4degN, 136.5degE). The annual variation of tritium in tree rings demonstrated two differences between the Shika-machi tree and the Tatsunokuchi-machi tree. No secondary peak appeared in the period after the maximum peak of 1963 for the Shika-machi tree, while two peaks appeared in 1966 and 1970 for the Tatsunokuchi-machi tree. In addition, the height of the 1963 peak was 30% higher for the Shika-machi tree than for the Tatsunokuchi-machi tree. These differences are considered to be caused by the influence that the underground water in the root zone of the Tatsunokuchi-machi tree was strongly affected by water which was transported to the tree site from mountain regions as compared to the Shika-machi tree. (author)

  10. Tropospheric Enhancement of Ozone over the UAE

    Science.gov (United States)

    Abbasi, Naveed Ali; Majeed, Tariq; Iqbal, Mazhar; Kaminski, Jacek; Struzewska, Joanna; Durka, Pawel; Tarasick, David; Davies, Jonathan

    2015-04-01

    We use the Global Environmental Multiscale - Air Quality (GEM-AQ) model to interpret the vertical profiles of ozone acquired with ozone sounding experiments at the meteorological site located at the Abu Dhabi airport. The purpose of this study is to gain insight into the chemical and dynamical structures in the atmosphere of this unique subtropical location (latitude 24.45N; longitude 54.22E). Ozone observations for years 2012 - 2013 reveal elevated ozone abundances in the range from 70 ppbv to 120 ppbv near 500-400 hPa during summer. The ozone abundances in other seasons are much lower than these values. The preliminary results indicate that summertime enhancement in ozone is associated with the Arabian anticyclones centered over the Zagros Mountains in Iran and the Asir and Hijaz Mountain ranges in Saudi Arabia, and is consistent with TES observations of deuterated water. The model also shows considerable seasonal variation in the tropospheric ozone which is transported from the stratosphere by dynamical processes. The domestic production of ozone in the middle troposphere is estimated and compared GEM-AQ model. It is estimated that about 40-50% of ozone in the UAE is transported from the neighbouring petrochemical industries in the Gulf region. We will present ozone sounding data and GEM-AQ results including a discussion on the high levels of the tropospheric ozone responsible for contaminating the air quality in the UAE. This work is supported by National Research Foundation, UAE.

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

    Directory of Open Access Journals (Sweden)

    R.M. Cox

    2001-01-01

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

  12. Balance of the tropospheric ozone and its relation to stratospheric intrusions indicated by cosmogenic radionuclides. Technical progress report, November 1, 1980-June 30, 1981

    International Nuclear Information System (INIS)

    Reiter, R.; Kanter, H.J.; Sladkovic, R.; Jaeger, H.; Munzert, K.H.

    1981-06-01

    The balance of the tropospheric ozone is studied with regard to sources and sinks. The influx of stratospheric ozone through stratospheric intrusions and photochemical production under pure air conditions is discussed. The 4-year measuring series (1977-1980) of the ozone concentration measured at 3 different levels are evaluated, the influence of meteorological parameters is examined. The time variation of the ozone layer between 1000 and 3000 m ASL is investigated as a function of different ozone sources. First results show that stratospheric ozone arriving at the troposphere penetrates only in a few rare cases to the ground layer below 1500 m ASL. Most of the time, the variation of ozone concentration in this layer is determined by photochemical processes which are, in turn, controlled by meteorological parameters. The upper boundary of the photochemically active layer is found at about 500 m above ground. Variability of the concentration of stratospheric aerosol and its optical properties after the volcanic eruptions in the year 1980 are discussed on the basis on lidar backscattering measurements

  13. Analysis of Ozone in Cloudy Versus Clear Sky Conditions

    Science.gov (United States)

    Strode, Sarah; Douglass, Anne; Ziemke, Jerald

    2016-01-01

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

  14. 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.

  15. Source attribution of tropospheric ozone

    Science.gov (United States)

    Butler, T. M.

    2015-12-01

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

  16. 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.

  17. 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.

  18. 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.

  19. Stratospheric ozone climatology and variability over a southern subtropical site: Reunion Island (21° S; 55° E

    Directory of Open Access Journals (Sweden)

    V. Sivakumar

    2007-11-01

    Full Text Available The study presents the climatological characteristics of stratospheric ozone observed over Reunion Island using in-situ (ozonesonde and SAOZ and satellite (UARS-HALOE, SAGE-II and TOMS measurements. It uses co-localised ozonesondes (from September 1992 to February 2005 and SAOZ measurements (from January 1993 to December 2004, SAGE-II data from October 1984 to February 1999 (~15 years, HALOE data from January 1991 to February 2005 (~15 years, and NIMBUS/TOMS data from January 1978 to December 2004 (27 years. The satellite measurements correspond to overpasses located nearby Reunion Island (21° S; 55° E. The height profiles of ozone concentration obtained from ozonesonde (0.5–29.5 km show less bias in comparison with the HALOE and SAGE-II measurements. Though, the satellite (HALOE and SAGE-II measurements underestimate the tropospheric ozone, they are in good agreement for the heights above 15 km. The bias between the measurements and the normalized ozone profile constructed from the ozonesonde and SAGE-II satellite measurement shows that the SAGE-II measurements are more accurate than the HALOE measurements in the lower stratosphere. The monthly variation of ozone concentration derived from ozonesonde and HALOE shows a nearly annual cycle with a maximum concentration during winter/spring and minimum concentration during summer/autumn months. The time evolution of total column ozone obtained from TOMS, SAOZ and the one computed from ozonesonde and SAGE-II, exhibits similar behaviour with analogous trends as above. The TOMS variation displays a higher value of total column ozone of about 3–5 DU (10% in comparison with the SAOZ and the integrated ozone from ozonesonde and SAGE-II.

  20. Sensitivity of the Reaction Mechanism of the Ozone Depletion Events during the Arctic Spring on the Initial Atmospheric Composition of the Troposphere

    Directory of Open Access Journals (Sweden)

    Le Cao

    2016-09-01

    Full Text Available Ozone depletion events (ODEs during the Arctic spring have been investigated since the 1980s. It was found that the depletion of ozone is highly associated with the release of halogens, especially bromine containing compounds. These compounds originate from various substrates such as the ice/snow-covered surfaces in Arctic. In the present study, the dependence of the mixing ratios of ozone and principal bromine species during ODEs on the initial composition of the Arctic atmospheric boundary layer was investigated by using a concentration sensitivity analysis. This analysis was performed by implementing a reaction mechanism representing the ozone depletion and halogen release in the box model KINAL (KInetic aNALysis of reaction mechanics. The ratios between the relative change of the mixing ratios of particular species such as ozone and the variation in the initial concentration of each atmospheric component were calculated, which indicate the relative importance of each initial species in the chemical kinetic system. The results of the computations show that the impact of various chemical species is different for ozone and bromine containing compounds during the depletion of ozone. It was found that CH3CHO critically controls the time scale of the complete removal of ozone. However, the rate of the ozone loss and the maximum values of bromine species are only slightly influenced by the initial value of CH3CHO. In addition, according to the concentration sensitivity analysis, the reduction of initial Br2 was found to cause a significant retardant of the ODE while the initial mixing ratio of HBr exerts minor influence on both ozone and bromine species. In addition, it is also interesting to note that the increase of C2H2 would significantly raise the amount of HOBr and Br in the atmosphere while the ozone depletion is hardly changed.

  1. Ozone as an ecotoxicological problem

    Energy Technology Data Exchange (ETDEWEB)

    Mortensen, L. [National Environmental Research Inst., Dept. of Atmospheric Environment, Roskilde (Denmark)

    1996-11-01

    Ozone is quantitatively the dominating oxidant in photochemical air pollution. Other compounds like hydrogen peroxide, aldehydes, formate, peroxyacetyl nitrate (PAN) and nitrogen dioxide are present too, and several of these are known to be phytotoxic, but under Danish conditions the concentration of these gases are without significance for direct effects on vegetation. Therefore, it is the effects of ozone on plant growth that will be described below. (EG) 65 refs.

  2. An algorithm for variational data assimilation of contact concentration measurements for atmospheric chemistry models

    Science.gov (United States)

    Penenko, Alexey; Penenko, Vladimir

    2014-05-01

    Contact concentration measurement data assimilation problem is considered for convection-diffusion-reaction models originating from the atmospheric chemistry study. High dimensionality of models imposes strict requirements on the computational efficiency of the algorithms. Data assimilation is carried out within the variation approach on a single time step of the approximated model. A control function is introduced into the source term of the model to provide flexibility for data assimilation. This function is evaluated as the minimum of the target functional that connects its norm to a misfit between measured and model-simulated data. In the case mathematical model acts as a natural Tikhonov regularizer for the ill-posed measurement data inversion problem. This provides flow-dependent and physically-plausible structure of the resulting analysis and reduces a need to calculate model error covariance matrices that are sought within conventional approach to data assimilation. The advantage comes at the cost of the adjoint problem solution. This issue is solved within the frameworks of splitting-based realization of the basic convection-diffusion-reaction model. The model is split with respect to physical processes and spatial variables. A contact measurement data is assimilated on each one-dimensional convection-diffusion splitting stage. In this case a computationally-efficient direct scheme for both direct and adjoint problem solution can be constructed based on the matrix sweep method. Data assimilation (or regularization) parameter that regulates ratio between model and data in the resulting analysis is obtained with Morozov discrepancy principle. For the proper performance the algorithm takes measurement noise estimation. In the case of Gaussian errors the probability that the used Chi-squared-based estimate is the upper one acts as the assimilation parameter. A solution obtained can be used as the initial guess for data assimilation algorithms that assimilate

  3. Effect of temperature variation on hormonal concentration at various gestation stages in black Bengal goat

    Directory of Open Access Journals (Sweden)

    Binod Kumar

    2015-09-01

    Full Text Available Aim: The present study was conducted to evaluate the effect of risingtemperature on the metabolic as well as the reproductive performance of the black Bengal goat. Materials and Methods: A total 27 numbers of non-pregnant black Bengal goats of the same parity comprised the experimental animals. The selected goats were randomly assigned to 3 groups of 9 each, maintaining uniformity in body weight (average 14-18 kg. Goats in Group-I were kept between the temperature ranges of 35-40°C, in Group-II between 20°Cand 27°C, and Group-III were kept under loose housing system and serve as a control. Goats in all the groups were bred naturally. Blood was collected prior to feeding in the morning on the day 1 (estrus, 20, 45, 90, and 135, expected day of parturition and also 2 days after parturition from goats of all the three groups. Results: It was observed that the level of plasma estrogen decreased (p˂0.05 up to day 45 of gestation, then after increased up to 135 days of gestation and was maximum on expected day of parturition which was significantly (p˂0.05 higher than all the values. Plasma progesterone level increased from day 20 and was the highest on day 90 and then decreased significantly (p˂0.05 on expected date of parturition. The luteinizing hormone value decreased significantly (p˂0.05 on expected day of parturition and day 2 after parturition in all the groups. Follicle stimulating hormone concentration showed a significant (p˂0.05 decrease from day 1 to 2 days after parturition in all the groups. The plasma triiodothyronine (T3 level did not vary between and within the treatment groups at any stage of the experiment. The plasma thyroxine (T4 level varied significantly (p˂0.01 within and (p˂0.05 between groups at all stages of reproduction. A significant (p<0.05 variation in plasma cortisol concentration in all the groups increased significantly until the day of parturition and dropped significantly (p<0.01 in 2 days after

  4. The behaviour of ozone and peroxyacetyl nitrate concentrations for different wind regimes during the MEDCAPHOT-TRACE campaign in the greater area of Athens, Greece

    DEFF Research Database (Denmark)

    Suppan, P.; Fabian, P.; Vyras, L.

    1998-01-01

    As a part of an international experimental field campaign, the association of air pollution with sea breeze circulation in the Greater Athens Area (GAA) is discussed on the basis of the behaviour of ozone and peroxyacetyl nitrate (PAN). During typical sea breeze days inside the Athens basin the o...... a straight line across the Athens basin ranging From the island of Aegina in the Gulf of Saronikos to the northern border of the GAA show distinct peaks due to the pollution cloud NEPHOS. (C) 1998 Published by Elsevier Science Ltd. All rights reserved....... the ozone levels reach values up to 66% greater than values outside the basin. There is also an increase in ozone and PAN mixing ratios from the south to the north and from lower to higher locations, within the GAA. On-line PAN-measurements with a time resolution of 5 min at three sites located almost along...

  5. Variation in predicted internal concentrations in relation to PBPK model complexity for rainbow trout

    Energy Technology Data Exchange (ETDEWEB)

    Salmina, E.S.; Wondrousch, D. [UFZ Department of Ecological Chemistry, Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig (Germany); Institute for Organic Chemistry, Technical University Bergakademie Freiberg, Leipziger Str. 29, 09596 Freiberg (Germany); Kühne, R. [UFZ Department of Ecological Chemistry, Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig (Germany); Potemkin, V.A. [Department of Chemistry, South Ural State Medical University, Vorovskogo 64, 454048, Chelyabinsk (Russian Federation); Schüürmann, G. [UFZ Department of Ecological Chemistry, Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig (Germany); Institute for Organic Chemistry, Technical University Bergakademie Freiberg, Leipziger Str. 29, 09596 Freiberg (Germany)

    2016-04-15

    The present study is motivated by the increasing demand to consider internal partitioning into tissues instead of exposure concentrations for the environmental toxicity assessment. To this end, physiologically based pharmacokinetic (PBPK) models can be applied. We evaluated the variation in accuracy of PBPK model outcomes depending on tissue constituents modeled as sorptive phases and chemical distribution tendencies addressed by molecular descriptors. The model performance was examined using data from 150 experiments for 28 chemicals collected from US EPA databases. The simplest PBPK model is based on the “K{sub ow}-lipid content” approach as being traditional for environmental toxicology. The most elaborated one considers five biological sorptive phases (polar and non-polar lipids, water, albumin and the remaining proteins) and makes use of LSER (linear solvation energy relationship) parameters to describe the compound partitioning behavior. The “K{sub ow}-lipid content”-based PBPK model shows more than one order of magnitude difference in predicted and measured values for 37% of the studied exposure experiments while for the most elaborated model this happens only for 7%. It is shown that further improvements could be achieved by introducing corrections for metabolic biotransformation and compound transmission hindrance through a cellular membrane. The analysis of the interface distribution tendencies shows that polar tissue constituents, namely water, polar lipids and proteins, play an important role in the accumulation behavior of polar compounds with H-bond donating functional groups. For compounds without H-bond donating fragments preferable accumulation phases are storage lipids and water depending on compound polarity. - Highlights: • For reliable predictions, models of a certain complexity should be compared. • For reliable predictions non-lipid fish tissue constituents should be considered. • H-donor compounds preferably accumulate in water

  6. Variation in predicted internal concentrations in relation to PBPK model complexity for rainbow trout

    International Nuclear Information System (INIS)

    Salmina, E.S.; Wondrousch, D.; Kühne, R.; Potemkin, V.A.; Schüürmann, G.

    2016-01-01

    The present study is motivated by the increasing demand to consider internal partitioning into tissues instead of exposure concentrations for the environmental toxicity assessment. To this end, physiologically based pharmacokinetic (PBPK) models can be applied. We evaluated the variation in accuracy of PBPK model outcomes depending on tissue constituents modeled as sorptive phases and chemical distribution tendencies addressed by molecular descriptors. The model performance was examined using data from 150 experiments for 28 chemicals collected from US EPA databases. The simplest PBPK model is based on the “K_o_w-lipid content” approach as being traditional for environmental toxicology. The most elaborated one considers five biological sorptive phases (polar and non-polar lipids, water, albumin and the remaining proteins) and makes use of LSER (linear solvation energy relationship) parameters to describe the compound partitioning behavior. The “K_o_w-lipid content”-based PBPK model shows more than one order of magnitude difference in predicted and measured values for 37% of the studied exposure experiments while for the most elaborated model this happens only for 7%. It is shown that further improvements could be achieved by introducing corrections for metabolic biotransformation and compound transmission hindrance through a cellular membrane. The analysis of the interface distribution tendencies shows that polar tissue constituents, namely water, polar lipids and proteins, play an important role in the accumulation behavior of polar compounds with H-bond donating functional groups. For compounds without H-bond donating fragments preferable accumulation phases are storage lipids and water depending on compound polarity. - Highlights: • For reliable predictions, models of a certain complexity should be compared. • For reliable predictions non-lipid fish tissue constituents should be considered. • H-donor compounds preferably accumulate in water, polar

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2003-07-01

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

  8. Variation of elemental concentration in hair of the Japanese in terms of age, sex and hair treatment

    International Nuclear Information System (INIS)

    Takeuchi, T.; Hayashi, T.; Takada, J.; Hayashi, Y.; Koyama, M.; Shinogi, M.; Aoki, A.; Tomiyama, T.; Katayama, K.

    1982-01-01

    Instrumental neutron activation analysis has been performed on human hair of the normal Japanese individuals to define the baseline levels of trace elements. A statistical analysis which is not influenced by detection limits, has been carried out to elucidate the variations of elemental concentrations in terms of age, sex and hair treatment. Correlation coefficients have been calculated between the logarithmic concentrations of the elements determined in the groups classified according to sex, age and hair treatment. Their significant levels have been evaluated. (author)

  9. Spatial and Seasonal Variation of dissolved organic carbon (DOC) concentrations in Irish streams: importance of soil and topography characteristics.

    Science.gov (United States)

    Liu, Wen; Xu, Xianli; McGoff, Nicola M; Eaton, James M; Leahy, Paul; Foley, Nelius; Kiely, Gerard

    2014-05-01

    Dissolved organic carbon (DOC) concentrations have increased in many sites in Europe and North America in recent decades. High DOC concentrations can damage the structure and functions of aquatic ecosystems by influencing water chemistry. This study investigated the spatial and seasonal variation of DOC concentrations in Irish streams across 55 sites at seven time occasions over 1 year (2006/2007). The DOC concentrations ranged from 0.9 to 25.9 mg/L with a mean value of 6.8 and a median value of 5.7 mg/L and varied significantly over the course of the year. The DOC concentrations from late winter (February: 5.2 ± 3.0 mg/L across 55 sites) and early spring (April: 4.5 ± 3.5 mg/L) had significantly lower DOC concentrations than autumn (October: mean 8.3 ± 5.6 mg/L) and early winter (December: 8.3 ± 5.1 mg/L). The DOC production sources (e.g., litterfall) or the accumulation of DOC over dry periods might be the driving factor of seasonal change in Irish stream DOC concentrations. Analysis of data using stepwise multiple linear regression techniques identified the topographic index (TI, an indication of saturation-excess runoff potential) and soil conditions (organic carbon content and soil drainage characteristics) as key factors in controlling DOC spatial variation in different seasons. The TI and soil carbon content (e.g., soil organic carbon; peat occurrence) are positively related to DOC concentrations, while well-drained soils are negatively related to DOC concentrations. The knowledge of spatial and seasonal variation of DOC concentrations in streams and their drivers are essential for optimum riverine water resources management.

  10. Temporal variations of methane concentration and isotopic composition in groundwater of the St. Lawrence Lowlands, eastern Canada

    Science.gov (United States)

    Rivard, Christine; Bordeleau, Geneviève; Lavoie, Denis; Lefebvre, René; Malet, Xavier

    2018-03-01

    Dissolved methane concentrations in shallow groundwater are known to vary both spatially and temporally. The extent of these variations is poorly documented although this knowledge is critical for distinguishing natural fluctuations from anthropogenic impacts stemming from oil and gas activities. This issue was addressed as part of a groundwater research project aiming to assess the risk of shale gas development for groundwater quality over a 500-km2 area in the St. Lawrence Lowlands (Quebec, Canada). A specific study was carried out to define the natural variability of methane concentrations and carbon and hydrogen isotope ratios in groundwater, as dissolved methane is naturally ubiquitous in aquifers of this area. Monitoring was carried out over a period of up to 2.5 years in seven monitoring wells. Results showed that for a given well, using the same sampling depth and technique, methane concentrations can vary over time from 2.5 to 6 times relative to the lowest recorded value. Methane isotopic composition, which is a useful tool to distinguish gas origin, was found to be stable for most wells, but varied significantly over time in the two wells where methane concentrations are the lowest. The use of concentration ratios, as well as isotopic composition of methane and dissolved inorganic carbon (DIC), helped unravel the processes responsible for these variations. This study indicates that both methane concentrations and isotopic composition, as well as DIC isotopes, should be regularly monitored over at least 1 year to establish their potential natural variations prior to hydrocarbon development.

  11. Circadian variation in serum cortisol during hydrocortisone replacement is not attributable to changes in cortisol-binding globulin concentrations.

    Science.gov (United States)

    Chung, T T; Gunganah, K; Monson, J P; Drake, W M

    2016-04-01

    Patients taking hydrocortisone (HC) replacement for primary or secondary adrenal failure require individual adjustment of their dose. In addition to modifying the administered doses of HC for each patient, physicians are increasingly interested in variations in the bioavailability of glucocorticoid replacement. One potential determinant of the bioavailability of replaced HC is a variation in serum cortisol-binding globulin (CBG) concentration, which may, in turn, affect interpretation of cortisol profiles and individual dose selection for patients on hydrocortisone replacement therapy. To investigate the hypothesis that there is a circadian variation in CBG levels. A total of 34 male patients divided into 3 groups (10 patients with non-somatotroph structural pituitary disease on HC replacement, 11 patients with treated acromegaly on HC replacement and 13 patients with treated acromegaly not on HC replacement) and 10 healthy volunteers were included. Cortisol and CBG levels were measured at 6 time points (0800, 1100, 1300, 1500, 1700 and 1900). No significant circadian variation in CBG concentration was found in any of the 4 groups. Circadian variation in serum cortisol during hydrocortisone replacement is not attributable to changes in cortisol-binding globulin concentration. Changes in serum cortisol levels may thus be explained by other factors including 11 β-hydroxysteroid dehydrogenase type 1 activity or circadian changes in the binding properties of CBG. © 2015 John Wiley & Sons Ltd.

  12. Geographic and temporal patterns of variation in total mercury concentrations in blood of harlequin ducks and blue mussels from Alaska.

    Science.gov (United States)

    Savoy, Lucas; Flint, Paul; Zwiefelhofer, Denny; Brant, Heather; Perkins, Christopher; Taylor, Robert; Lane, Oksana; Hall, Jeff; Evers, David; Schamber, Jason

    2017-04-15

    We compared total mercury (Hg) concentrations in whole blood of harlequin ducks (Histrionicus histrionicus) sampled within and among two geographically distinct locations and across three years in southwest Alaska. Blue mussels were collected to assess correlation between Hg concentrations in locally available forage and birds. Mercury concentrations in harlequin duck blood were significantly higher at Unalaska Island (0.31±0.19 mean±SD, μg/g blood) than Kodiak Island (0.04±0.02 mean±SD, μg/g blood). We found no evidence for annual variation in blood Hg concentration between years at Unalaska Island. However, blood Hg concentration did vary among specific sampling locations (i.e., bays) at Unalaska Island. Findings from this study demonstrate harlequin ducks are exposed to environmental sources of Hg, and whole blood Hg concentrations are associated with their local food source. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Seasonal variation of air pollution in Warsaw conurbation

    Directory of Open Access Journals (Sweden)

    Katarzyna Rozbicka

    2014-09-01

    Full Text Available Long term research shows many substances in the atmosphere are in concentration dangerous for human health and welfare and even for human life. The work presents time and spatial variation of tropospheric ozone and nitrogen dioxide concentrations. Analysis was carried out on the base of hourly values of mentioned pollutants (O3 and NO2 concentrations. Data used in the analysis comes from atmospheric monitoring stations situated in various parts of Warsaw and concerns the period 2008–2011. The influence of meteorological elements on concentration of analyzed pollutants was stated by the use of correlation and multiple regression analysis for months and seasonal periods. On this base results of statistical analysis strong correlation between tropospheric ozone, nitrogen dioxide concentration and meteorological elements is stated. In case of ozone and nitrogen dioxide the relationships with air temperature, relative humidity and solar radiation are most significant.

  14. The seasonal variation of radon concentration in the atmosphere of Chichi-jima island in the pacific ocean

    International Nuclear Information System (INIS)

    Yoshioka, Katsuhiro

    2008-01-01

    We continuously measured the radon concentration from April 2001 to December 2004 in Chichi-jima Is. We expect that the radon concentration at Chichi-jima Is. would be influenced only by the air mass transported through the long distance. The hourly values had very large variations, ranging from 0.2 to 6.0 Bqm -3 . No diurnal periodicity was found in the variation of the radon concentration. We found that the monthly averages of the radon concentration had a clear long term pattern, showing the highest in the winter and the lowest in the summer. To analyze the radon long time variation, an arriving air mass is grouped into five sectors according to the backward trajectory. Sector I is the sea areas surrounding Chichi-jima Is. Sector II including Philippines, Indonesia and the southeast Asia is spread the southwestern Pacific Ocean from Chichi-jima Is. and sector V is spread the northeastern way to the southeast. Sector III includes China, Mongolia, Korea and the western Japan region and sector IV two regions of the eastern Siberia and the eastern Japan. The radon long time variation showed a high positive correlation between the number of arrivals of the continental air mass, while strong negative correlation between the maritime air mass. (author)

  15. Possible causes of variation in acrylamide concentration in French fries prepared in food service establishments: an observational study

    NARCIS (Netherlands)

    Sanny, M.A.I.; Jinap, S.; Bakker, E.J.; Boekel, van M.A.J.S.; Luning, P.A.

    2012-01-01

    Acrylamide is a probable human carcinogen, and its presence in a range of fried and oven-cooked foods has raised considerable health concern world-wide. Dietary intake studies observed significant variations in acrylamide concentrations, which complicate risk assessment and the establishment of

  16. Serum uric acid concentrations and SLC2A9 genetic variation in Hispanic children: The Viva La Familia Study

    Science.gov (United States)

    Elevated concentrations of serum uric acid are associated with increased risk of gout and renal and cardiovascular diseases. Genetic studies in adults have consistently identified associations of solute carrier family 2, member 9 (SLC2A9), polymorphisms with variation in serum uric acid. However, it...

  17. Biological control of short-term variations in the concentration of DMSP and DMS during a Phaeocystis spring bloom

    NARCIS (Netherlands)

    van Duyl, FC; Gieskes, WWC; Kop, AJ; Lewis, WE

    1998-01-01

    In the spring of 1995. short-term variations in the concentration of particulate and dissolved dimethylsulfoniopropionate (DMSP) and dimethylsulfide (DMS) were monitored in the western Wadden Sea, a shallow coastal region in open connection with the North Sea. Significant correlations were found

  18. Variation of NO2 and NOx concentrations between and within 36 European study areas: Results from the ESCAPE study

    NARCIS (Netherlands)

    Cyrys, J.; Eeftens, M.R.|info:eu-repo/dai/nl/315028300; Heinrich, J.; Ampe, C.; Armengaud, A.; Beelen, R.; Bellander, T.; Beregszaszi, T.; Birk, M.; Cesaroni, G.; Cirach, M.; de Hoogh, K.; de Nazelle, A.; de Vocht, F.; Declercq, C.; Dėdelė, A.; Dimakopoulou, K.; Eriksen, K.; Galassi, C.; Grąulevičienė, R.; Grivas, G.; Gruzieva, O.; Gustafsson, A.H.; Hoffmann, B.; Iakovides, M.; Ineichen, A.; Krämer, U.; Lanki, T.; Lozano, P.; Madsen, C.; Meliefste, K.; Modig, L.; Mölter, A.; Mosler, G.; Nieuwenhuijsen, M.; Nonnemacher, M.; Oldenwening, M.; Peters, A.; Pontet, S.; Probst-Hensch, N.; Quass, U.; Raaschou-Nielsen, O.; Ranzi, A.; Sugiri, D.; Stephanou, E.G.; Taimisto, P.; Tsai, M-Y.; Vaskövi, É.; Villani, S.; Wang, M.|info:eu-repo/dai/nl/345480279; Brunekreef, B.|info:eu-repo/dai/nl/067548180; Hoek, G.|info:eu-repo/dai/nl/069553475

    2012-01-01

    The ESCAPE study (European Study of Cohorts for Air Pollution Effects) investigates long-term effects of exposure to air pollution on human health in Europe. This paper documents the spatial variation of measured NO2 and NOx concentrations between and within 36 ESCAPE study areas across Europe. In

  19. 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.

  20. Do the earth tides have an influence on short-term variations in radon concentration?

    International Nuclear Information System (INIS)

    Barnet, I.; Prochazka, J.; Skalsky, L.

    1997-01-01

    The short term (diurnal) indoor radon variations are often explained as a result of temperature and air pressure changes inside a dwelling (the so-called stack effect). The observations of indoor and soil gas radon variations related to the temperature and pressure variations in a test dwelling at Lipova, Northern Bohemia, have not proved the expected correlation between the radon and climatic parameters. The stack effect was clearly observed at the beginning of the four week cycles, when the indoor temperature growth was obvious. However, the indoor radon variations were of the same range or higher than at the beginning of the cycles during the whole week cycles, even when the temperature changes were of the 1-3 o C range. A theory is therefore presented, supported by the known fluctuations of the groundwater level caused by the Earth tides, and the widely observed free air radon variations. According to this theory, the Earth tides lead to the compression of the aquifers and synchronous rise of the groundwater level, which displaces the soil gas with radon into the atmosphere or dwellings. The Earth tide components were calculated for the studied locality and time intervals. The very good phase fit of the amplitudes of gravity variations, vertical and volume strain and vertical displacement with the indoor radon variations was found. This agreement leads to the conclusion that the Earth tides can be considered as one of the causes of the indoor radon variations. This conclusion is also supported by the observations of the radon variations in the underground unventilated spaces under constant temperature and air pressure conditions. (Author)

  1. 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.

  2. Concentration, ozone formation potential and source analysis of volatile organic compounds (VOCs) in a thermal power station centralized area: A study in Shuozhou, China.

    Science.gov (United States)

    Yan, Yulong; Peng, Lin; Li, Rumei; Li, Yinghui; Li, Lijuan; Bai, Huiling

    2017-04-01

    Volatile organic compounds (VOCs) from two sampling sites (HB and XB) in a power station centralized area, in Shuozhou city, China, were sampled by stainless steel canisters and measured by gas chromatography-mass selective detection/flame ionization detection (GC-MSD/FID) in the spring and autumn of 2014. The concentration of VOCs was higher in the autumn (HB, 96.87 μg/m 3 ; XB, 58.94 μg/m 3 ) than in the spring (HB, 41.49 μg/m 3 ; XB, 43.46 μg/m 3 ), as lower wind speed in the autumn could lead to pollutant accumulation, especially at HB, which is a new urban area surrounded by residential areas and a transportation hub. Alkanes were the dominant group at both HB and XB in both sampling periods, but the contribution of aromatic pollutants at HB in the autumn was much higher than that of the other alkanes (11.16-19.55%). Compared to other cities, BTEX pollution in Shuozhou was among the lowest levels in the world. Because of the high levels of aromatic pollutants, the ozone formation potential increased significantly at HB in the autumn. Using the ratio analyses to identify the age of the air masses and analyze the sources, the results showed that the atmospheric VOCs at XB were strongly influenced by the remote sources of coal combustion, while at HB in the spring and autumn were affected by the remote sources of coal combustion and local sources of vehicle emission, respectively. Source analysis conducted using the Positive Matrix Factorization (PMF) model at Shuozhou showed that coal combustion and vehicle emissions made the two largest contributions (29.98% and 21.25%, respectively) to atmospheric VOCs. With further economic restructuring, the influence of vehicle emissions on the air quality should become more significant, indicating that controlling vehicle emissions is key to reducing the air pollution. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Ozone Layer Protection

    Science.gov (United States)

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

  4. The 2002 Antarctic Ozone Hole

    Science.gov (United States)

    Newman, P. A.; Nash, E. R.; Douglass, A. R.; Kawa, S. R.

    2003-01-01

    Since 1979, the ozone hole has grown from near zero size to over 24 Million km2. This area is most strongly controlled by levels of inorganic chlorine and bromine oncentrations. In addition, dynamical variations modulate the size of the ozone hole by either cooling or warming the polar vortex collar region. We will review the size observations, the size trends, and the interannual variability of the size. Using a simple trajectory model, we will demonstrate the sensitivity of the ozone hole to dynamical forcing, and we will use these observations to discuss the size of the ozone hole during the 2002 Austral spring. We will further show how the Cly decreases in the stratosphere will cause the ozone hole to decrease by 1-1.5% per year. We will also show results from a 3-D chemical transport model (CTM) that has been continuously run since 1999. These CTM results directly show how strong dynamics acts to reduce the size of the ozone hole.

  5. Temporal variations of radon concentration in the saturated soil of Alpine grassland: The role of groundwater flow

    International Nuclear Information System (INIS)

    Perrier, Frederic; Richon, Patrick; Sabroux, Jean-Christophe

    2009-01-01

    Radon concentration has been monitored from 1995 to 1999 in the soil of the Sur-Fretes ridge (French Alps), covered with snow from November to April. Measurements were performed at 70 cm depth, with a sampling time of 1 h, at two points: the summit of the ridge, at an altitude of 1792 m, and the bottom of the ridge, at an altitude of 1590 m. On the summit, radon concentration shows a moderate seasonal variation, with a high value from October to April (winter), and a low value from May to September (summer). At the bottom of the ridge, a large and opposite seasonal variation is observed, with a low value in winter and a high value in summer. Fluctuations of the radon concentration seem to be associated with temperature variations, an effect which is largely delusory. Indeed, these variations are actually due to water infiltration. A simplified mixing model is used to show that, at the summit of the ridge, two effects compete in the radon response: a slow infiltration response, rich in radon, with a typical time scale of days, and a fast infiltration of radon-poor rainwater. At the bottom of the ridge, similarly, two groundwater contributions compete: one slow infiltration response, similar to the response seen at the summit, and an additional slower response, with a typical time scale of about a month. This second slower response can be interpreted as the aquifer discharge in response to snow melt. This study shows that, while caution is necessary to properly interpret the various effects, the temporal variations of the radon concentration in soil can be understood reasonably well, and appear to be a sensitive tool to study the subtle interplay of near surface transfer processes of groundwater with different transit times

  6. Temporal variations of radon concentration in the saturated soil of Alpine grassland: the role of groundwater flow.

    Science.gov (United States)

    Perrier, Frédéric; Richon, Patrick; Sabroux, Jean-Christophe

    2009-03-15

    Radon concentration has been monitored from 1995 to 1999 in the soil of the Sur-Frêtes ridge (French Alps), covered with snow from November to April. Measurements were performed at 70 cm depth, with a sampling time of 1 h, at two points: the summit of the ridge, at an altitude of 1792 m, and the bottom of the ridge, at an altitude of 1590 m. On the summit, radon concentration shows a moderate seasonal variation, with a high value from October to April (winter), and a low value from May to September (summer). At the bottom of the ridge, a large and opposite seasonal variation is observed, with a low value in winter and a high value in summer. Fluctuations of the radon concentration seem to be associated with temperature variations, an effect which is largely delusory. Indeed, these variations are actually due to water infiltration. A simplified mixing model is used to show that, at the summit of the ridge, two effects compete in the radon response: a slow infiltration response, rich in radon, with a typical time scale of days, and a fast infiltration of radon-poor rainwater. At the bottom of the ridge, similarly, two groundwater contributions compete: one slow infiltration response, similar to the response seen at the summit, and an additional slower response, with a typical time scale of about a month. This second slower response can be interpreted as the aquifer discharge in response to snow melt. This study shows that, while caution is necessary to properly interpret the various effects, the temporal variations of the radon concentration in soil can be understood reasonably well, and appear to be a sensitive tool to study the subtle interplay of near surface transfer processes of groundwater with different transit times.

  7. Reduction of intensity variations on a photovoltaic array with compound parabolic concentrators

    Science.gov (United States)

    Greenman, P.; Ogallagher, J.; Winston, R.; Costogue, E.

    1979-01-01

    The reduction of nonuniformities in the intensity distribution of light focused on a photovoltaic array by a compound parabolic concentrator is investigated. The introduction of small distortions into the surfaces of the reflector in order to diffuse the incident collimated light to fill the angular acceptance of the concentrator is calculated by means of ray tracing to decrease the irradiance nonuniformity at the cost of a lowered effective concentration of the concentrator. Measurements of the intensity distribution on a scale test model in terrestrial sunlight with corrugated aluminized mylar reflectors are shown to be in good agreement with the ray tracing results. A two-stage concentrator consisting of a focusing primary and a nonimaging secondary is also shown to result in a fairly uniform intensity distribution except in the case of a 4-deg incidence angle, which may be corrected by the introduction of distortions into one or both concentration stages.

  8. Variability of the stratospheric ozone in Colombia

    International Nuclear Information System (INIS)

    Aristizabal, Gloria Leon

    2002-01-01

    In this study has been examined the causes of ozone variations and the sign that represent in the short-term, seasonal, interannual, decadal and long-term variability. The analysis of NASA satellite data sets, obtained with the total ozone mapping spectrometer toms, for the period 1979-1999, they permit to deduce to the total column ozone that in Colombia, varies among 255 and 267 U.D., and presents synchronous variations with the quasi biennial oscillation (QBO) and in the series not any tendency with the time is recognized

  9. 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...

  10. The Copper concentration variation to physical properties of high copper amalgam alloy

    Directory of Open Access Journals (Sweden)

    Aminatun Aminatun

    2006-09-01

    Full Text Available The function of copper (Cu inside amalgam is to increase hardness and impact force and to decrease thermal expansion coefficient. In general, amalgam which is used in dentistry and available in the market is contain Cu 22%, while the maximum Cu concentration is 30%. It is necessary to determine the concentration Cu does generate the best physical properties to be used as dental restorative agent. Amalgam is made by mixing blended-metal Ag-Sn-Cu (with Cu concentration of 13%, 21%, 22%, and 29% and Hg, stirred manually in a bowl for 15 minutes,leave it in temperature 27°C for 24 hours to become hardened. The result of X-Ray Diffractometer (XRD, analyzed by Rietveld method and Rietica program, shows amalgam with Cu 29% concentration for Cu3Sn compound density is 31.790 sma/Å3, for Ag2Hg3 compound is 41.733 sma/ Å3, a Cu3Sn relative weight percentage of 43.23%, Ag2Hg3 of 54.54%, Cu 7Hg6 of 2.23% and hardness of Cu 29% is 90.700 ± 0.005 kgf/mm2. These numbers are the highest values on Cu 29% concentrations compared to other copper concentration variants. Whereas amalgam thermal expansion coefficient on Cu 29% is (2.17 ± 0.9110-3 mm/°C is the lowest value compared to other Cu concentration. The conclution is that adding Cu concentration into amalgam will increase density value, Cu3Sn relative weight percentage, hardness level and will decrease amalgam thermal expansion coefficient. Amalgam 29% Cu concentration has better physical properties compared to amalgam Cu 22% concentration.

  11. 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.

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

    NARCIS (Netherlands)

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

    2015-01-01

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

  13. Variation of radiocesium concentrations in cedar pollen in the Okutama area since the Fukushima Daiichi Nuclear Power Plant accident

    International Nuclear Information System (INIS)

    Tsuruoka, H.; Inoue, K.; Sakano, Y.; Hamada, M.; Shimizu, H.; Fukushi, M.

    2015-01-01

    Due to releases of radionuclides in the Fukushima Daiichi Nuclear Power Plant accident, radiocesium ( 134 Cs and 137 Cs) has been incorporated into large varieties of plant species and soil types. There is a possibility that radiocesium taken into plants is being diffused by pollen. Radiocesium concentrations in cedar pollen have been measured in Ome City, located in the Okutama area of metropolitan Tokyo, for the past 3 y. In this research, the variation of radiocesium concentrations was analysed by comparing data from 2011 to 2014. Air dose rates at 1 m above the ground surface in Ome City from 2011 to 2014 showed no significant difference. Concentration of 137 Cs contained in the cedar pollen in 2012 was about half that in 2011. Between 2012 and 2014, the concentration decreased by approximately one-fifth, which was similar to the result of a press release distributed by the Japanese Ministry of Agriculture, Forestry and Fisheries. (authors)

  14. 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.

  15. Variation in the iodine concentrations of foods: considerations for dietary assessment1234

    Science.gov (United States)

    Carriquiry, Alicia L; Spungen, Judith H; Murphy, Suzanne P; Pehrsson, Pamela R; Dwyer, Johanna T; Juan, WenYen; Wirtz, Mark S

    2016-01-01

    Background: Food-composition tables typically give measured nutrient concentrations in foods as a single summary value, often the mean, without providing information as to the shape of the distribution. Objective: Our objective was to explore how the statistical approach chosen to describe the iodine concentrations of foods affects the proportion of the population identified as having either insufficient or excessive iodine intakes. Design: We used food intake data reported by the 2009−2010 NHANES and measured iodine concentrations of Total Diet Study (TDS) foods from 4 US regions sampled in 2004–2011. We created 4 data sets, each by using a different summary statistic (median, mean, and 10th and 90th percentiles), to represent the iodine concentration distribution of each TDS food. We estimated the iodine concentration distribution of each food consumed by NHANES participants as the 4 iodine concentration summary statistics of a similar TDS food and used these, along with NHANES food intake data, to develop 4 estimates of each participant’s iodine intake on each survey day. Using the 4 estimates in turn, we calculated 4 usual iodine intakes for each sex- and age-specific subgroup. We then compared these to guideline values and developed 4 estimates of the proportions of each subgroup with deficient and excessive usual iodine intakes. Results: In general, the distribution of iodine intakes was poorly characterized when food iodine concentrations were expressed as mean values. In addition, mean values predicted lower prevalences of iodine deficiency than did median values. For example, in women aged 19–50 y, the estimated prevalence of iodine deficiency was 25% when based on median food iodine concentrations but only 5.8% when based on mean values. Conclusion: For nutrients such as iodine with highly variable concentrations in important food sources, we recommend that food-composition tables provide useful variability information, including the mean, SD, and

  16. Study on the concentration and seasonal variation of inorganic elements in 35 species of marine algae

    DEFF Research Database (Denmark)

    Hou, Xiaolin; Yan, X.J.

    1998-01-01

    The concentrations of five major and 28 trace elements in 35 marine algae collected along the coast of China were determined by instrumental neutron activation analysis. The concentrations of halogens, rare earth elements and many transition metal elements in marine algae are remarkably higher than...... those in terrestrial plants. The concentration factors for 31 elements in all collected algae were calculated, those for tri- and tetra-valent elements were higher than those of the mono- and di-valent elements in marine algae. The biogeochemical characteristics of inorganic elements in marine algae...

  17. Seasonal variations in the concentration and solubility of elements in atmospheric particulate matter: a case study in Northern Italy

    Directory of Open Access Journals (Sweden)

    Canepari S.

    2013-04-01

    Full Text Available Atmospheric particulate matter is characterized by a variety of chemical components, generally produced by different sources. Chemical fractionation of elements, namely the determination of their extractable and residual fractions, may reliably increase the selectivity of some elements as tracers of specific PM sources. Seasonal variations of atmospheric particulate matter concentration in PM10 and PM2.5, of elemental concentration in PM10 and PM2.5, of the extractable and residual fraction of elements in different size fractions in the range 0.18 – 18 μm are reported in this paper. The effect of the ageing of the air masses is discussed.

  18. Racial and ethnic variations in phthalate metabolite concentration changes across full-term pregnancies.

    Science.gov (United States)

    James-Todd, Tamarra M; Meeker, John D; Huang, Tianyi; Hauser, Russ; Seely, Ellen W; Ferguson, Kelly K; Rich-Edwards, Janet W; McElrath, Thomas F

    2017-03-01

    Higher concentrations of certain phthalate metabolites are associated with adverse reproductive and pregnancy outcomes, as well as poor infant/child health outcomes. In non-pregnant populations, phthalate metabolite concentrations vary by race/ethnicity. Few studies have documented racial/ethnic differences between phthalate metabolite concentrations at multiple time points across the full-course of pregnancy. The objective of the study was to characterize the change in phthalate metabolite concentrations by race/ethnicity across multiple pregnancy time points. Women were participants in a prospectively collected pregnancy cohort who delivered at term (≥37 weeks) and had available urinary phthalate metabolite concentrations for ≥3 time points across full-term pregnancies (n=350 women). We assessed urinary concentrations of eight phthalate metabolites that were log-transformed and specific gravity-adjusted. We evaluated the potential racial/ethnic differences in phthalate metabolite concentrations at baseline (median 10 weeks gestation) using ANOVA and across pregnancy using linear mixed models to calculate the percent change and 95% confidence intervals adjusted for sociodemographic and lifestyle factors. Almost 30% of the population were non-Hispanic black or Hispanic. With the exception of mono-(3-carboxypropyl) (MCPP) and di-ethylhexyl phthalate (DEHP) metabolites, baseline levels of phthalate metabolites were significantly higher in non-whites (Pethnicity, mono-ethyl phthalate (MEP) and MCPP had significant percent changes across pregnancy. MEP was higher in Hispanics at baseline and decreased in mid-pregnancy but increased in late pregnancy for non-Hispanic blacks. MCPP was substantially higher in non-Hispanic blacks at baseline but decreased later in pregnancy. Across pregnancy, non-Hispanic black and Hispanic women had higher concentrations of certain phthalate metabolites. These differences may have implications for racial/ethnic differences in adverse

  19. Performance and microbial community variations of anaerobic digesters under increasing tetracycline concentrations

    KAUST Repository

    Xiong, Yanghui; Harb, Moustapha; Hong, Pei-Ying

    2017-01-01

    The impact of different concentrations of tetracycline on the performance of anaerobic treatment was evaluated. Results revealed that for all of the tested tetracycline concentrations, no major sustained impact on methane production was observed. Instead, a significant increase in propionic acid was observed in the reactor subjected to the highest concentration of tetracycline (20 mg/L). Microbial community analyses suggest that an alternative methanogenic pathway, specifically that of methanol-utilizing methanogens, may be important for ensuring the stability of methane production in the presence of high tetracycline concentrations. In addition, the accumulation of propionate was due to an increase in volatile fatty acids (VFA)-producing bacteria coupled with a reduction in propionate utilizers. An increase in the abundance of tetracycline resistance genes associated with ribosomal protection proteins was observed after 30 days of exposure to high concentrations of tetracycline, while other targeted resistance genes showed no significant changes. These findings suggest that anaerobic treatment processes can robustly treat wastewater with varying concentrations of antibiotics while also deriving value-added products and minimizing the dissemination of associated antibiotic resistance genes.

  20. Performance and microbial community variations of anaerobic digesters under increasing tetracycline concentrations

    KAUST Repository

    Xiong, Yanghui

    2017-04-01

    The impact of different concentrations of tetracycline on the performance of anaerobic treatment was evaluated. Results revealed that for all of the tested tetracycline concentrations, no major sustained impact on methane production was observed. Instead, a significant increase in propionic acid was observed in the reactor subjected to the highest concentration of tetracycline (20 mg/L). Microbial community analyses suggest that an alternative methanogenic pathway, specifically that of methanol-utilizing methanogens, may be important for ensuring the stability of methane production in the presence of high tetracycline concentrations. In addition, the accumulation of propionate was due to an increase in volatile fatty acids (VFA)-producing bacteria coupled with a reduction in propionate utilizers. An increase in the abundance of tetracycline resistance genes associated with ribosomal protection proteins was observed after 30 days of exposure to high concentrations of tetracycline, while other targeted resistance genes showed no significant changes. These findings suggest that anaerobic treatment processes can robustly treat wastewater with varying concentrations of antibiotics while also deriving value-added products and minimizing the dissemination of associated antibiotic resistance genes.

  1. Performance and microbial community variations of anaerobic digesters under increasing tetracycline concentrations.

    Science.gov (United States)

    Xiong, Yanghui; Harb, Moustapha; Hong, Pei-Ying

    2017-07-01

    The impact of different concentrations of tetracycline on the performance of anaerobic treatment was evaluated. Results revealed that for all of the tested tetracycline concentrations, no major sustained impact on methane production was observed. Instead, a significant increase in propionic acid was observed in the reactor subjected to the highest concentration of tetracycline (20 mg/L). Microbial community analyses suggest that an alternative methanogenic pathway, specifically that of methanol-utilizing methanogens, may be important for ensuring the stability of methane production in the presence of high tetracycline concentrations. In addition, the accumulation of propionate was due to an increase in volatile fatty acids (VFA)-producing bacteria coupled with a reduction in propionate utilizers. An increase in the abundance of tetracycline resistance genes associated with ribosomal protection proteins was observed after 30 days of exposure to high concentrations of tetracycline, while other targeted resistance genes showed no significant changes. These findings suggest that anaerobic treatment processes can robustly treat wastewater with varying concentrations of antibiotics while also deriving value-added products and minimizing the dissemination of associated antibiotic resistance genes.

  2. Concentration variations of the tropospheric carbon dioxide over the Antarctic region

    Directory of Open Access Journals (Sweden)

    Shohei Murayama

    1997-03-01

    Full Text Available Aircraft measurements of the atmospheric CO_2 concentration have been made over Syowa Station, Antarctica since 1983. The minimum concentration of the average seasonal CO_2 cycle appears in March throughout the troposphere, while the maximum concentration occurs in mid-August in the upper troposphere and in late September in the middle and lower troposphere. The peak-to-peak amplitude of the seasonal cycle decreases with height. The CO_2 concentration increases with height during most of the year; however, this height dependency is larger from summer to early winter than in the remaining seasons. The average concentration difference between the upper troposphere and the ground surface is about 0.3ppmv. From comparisons with the results of the ground-based and aircraft measurements at southern middle and high latitudes and trajectory analysis, it is hypothesized that the seasonal cycle of height-dependent atmospheric transport processes could influence the seasonal cycle and the vertical distribution of the CO_2 concentration over Syowa Station.

  3. Variation in markup of general surgical procedures by hospital market concentration.

    Science.gov (United States)

    Cerullo, Marcelo; Chen, Sophia Y; Dillhoff, Mary; Schmidt, Carl R; Canner, Joseph K; Pawlik, Timothy M

    2018-04-01

    Increasing hospital market concentration (with concomitantly decreasing hospital market competition) may be associated with rising hospital prices. Hospital markup - the relative increase in price over costs - has been associated with greater hospital market concentration. Patients undergoing a cardiothoracic or gastrointestinal procedure in the 2008-2011 Nationwide Inpatient Sample (NIS) were identified and linked to Hospital Market Structure Files. The association between market concentration, hospital markup and hospital for-profit status was assessed using mixed-effects log-linear models. A weighted total of 1,181,936 patients were identified. In highly concentrated markets, private for-profit status was associated with an 80.8% higher markup compared to public/private not-for-profit status (95%CI: +69.5% - +96.9%; p markup compared to public/private not-for-profit status in unconcentrated markets (95%CI: +45.4% - +81.1%; p markup. Government and private not-for-profit hospitals employed lower markups in more concentrated markets, whereas private for-profit hospitals employed higher markups in more concentrated markets. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Seasonal Variations of Isotope Ratios and CO2 Concentrations in Firn Air

    OpenAIRE

    Weiler, Karin; Schwander, Jakob; Leuenberger, Markus; Blunier, Thomas; Mulvaney, Robert; Anderson, Philip S.; Salmon, Rhian; Sturges, William T.

    2009-01-01

    A first year-round firn air sampling carried out at the British Antarctic station Halley in 2003 shows isotope and CO2 changes owing to diffusive mixing driven by seasonal variations of surface temperature, and gas composition of the atmosphere. Seasonal firn temperatures are well reproduced from the atmospheric temperature history. Based on these profiles thermal diffusion is forced with thermal diffusion factors αT with respect to air. Application of the available literature data for αT (15...

  5. Short-term temporal variations of soil gas radon concentration and comparison of measurement techniques

    Czech Academy of Sciences Publication Activity Database

    Neznal, M.; Matolín, M.; Just, G.; Turek, Karel

    2004-01-01

    Roč. 108, č. 1 (2004), s. 55-63 ISSN 0144-8420 R&D Projects: GA AV ČR KSK2067107; GA AV ČR KSK4055109 Grant - others:Projekt SÚJB(CZ) R/2/2000 Institutional research plan: CEZ:AV0Z1048901 Keywords : radon * soil gas * temporal variations Subject RIV: DL - Nuclear Waste, Radioactive Pollution ; Quality Impact factor: 0.617, year: 2003

  6. 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 thi