Comparison of temporal and Spatial Characteristics of Ozone Pollution at Ground Level in the Eastern China

Monitoring data from ozone（O3） automatic stations in three typical cities with different climatic areas in the southern and northern parts of eastern China are used to analyze temporal and spatial characteristics of ozone pollution at ground level. The results show that ozone pollution level has distinct regional differences and the concentration in the suburbs is higher than that in the urban areas. The seasonal variation of ozone concentration in different climatic areas is greatly affected by the variation of precipitation. Ozone concentration in Shenyang and Beijing , in the temperate zone, has one perennial peak concentration, occurring in early summer, May or June. Ozone concentration in Guangzhou, in sub-tropical zone, has two peak values year round. The highest values occur in October and the secondary high value in June. The ozone season in the south is longer than that in the north. The annual average daily peak value of ozone concentrations in different climates usually occur around 3 pm. The diurnal variation range of ozone concentration declines with the increase of latitude. Ozone concentration does not elevate with the increase of traffic flow. Ozone concentration in Guangzhou has a distinct reverse relation to CO and NOx. This complicated non-linearity indicates that the equilibrium of ozone photochemical reaction has regional differences. Exceeding the rate of Beijing＇s lh ozone concentration is higher than that of Guangzhou, whereas the average 8h ozone level is lower than that of Guangzhou, indicating that areas in low latitude are more easily affected by moderate ozone concentrations and longer exposure. Thus, China should work out standards for 8h ozone concentration.     

上海城区典型臭氧浓度偏低年的成因分析

利用2006~2010年上海徐家汇、崇明、宝山、金山和浦东5个监测站的臭氧资料,分析了上海地区不同功能区臭氧的浓度特征及年际变化特征。结果表明：2006年上海地区臭氧平均浓度是这5 a的最低值,以徐家汇和浦东两个站臭氧浓度年际差异最为明显。2006年各站春末和夏季的臭氧浓度明显低于其他年份,而秋冬季臭氧浓度却差别不大。以徐家汇地区为例的综合分析表明,天气状况、日照时数、温度和风速等气象要素不是造成2006年上海城区臭氧浓度偏低的原因,臭氧前体物（VOCs和NOx）才是造成这种现象的主要原因。2006年4~8月NOx和VOCs浓度明显偏低,典型臭氧日变化情况下2006年VOCs/NOx比值较小,平均值为1.22,比2007、2008年低了近65%,而O3的生产率也分别减少了65%和59%。OZIPR模式的结果也表明较低的VOCs浓度以及VOCs/NOx比值,是导致2006年上海城区臭氧浓度偏低的主要原因     

Use of kriging models to predict 12-hour mean ozone concentrations in Metropolitan Toronto-A pilot study

Ozone concentrations exhibit spatial variability within metropolitan areas, resulting in significantly different personal exposures among individuals. This paper uses the statistical technique, kriging, to explore the 12-h daytime (8am–8pm) ozone spatial variation and to predict mean outdoor ozone levels at home sites within the Toronto metropolitan area. Outdoor ozone measurements taken in the Toronto metropolitan area between June and August 1992 are used in kriging models to predict outdoor ozone concentrations. The performance of the model is evaluated by comparing actual home outdoor measurements with predicted values. Results indicate that kriging predictions are more accurate than using only the closest stationary ambient site measurements for determining home outdoor ozone concentrations within the metropolitan area. The average variogram obtained from pooling data throughout the entire sampling period shows a clear spatial trend in the outdoor ozone variation. Kriging predictions using the parameters from the average variogram perform as well as those using variograms from individual days. An approach for minimizing sample bias can be used to increase the accuracy of the predictions; cross-validation suggests that it is a reasonable procedure.     

Surface ozone trends in Hong Kong in 1985-1995

Ozone trends in Hong Kong were assessed from the ozone data recorded at three urban stations and one station in the new development area. Three parameters were selected as the robust trend indicators in the study: monthly mean, monthly averaged daily 1-h maximum, and number of annual hours > 120 microg m(-3). As the ozone data displayed obvious seasonal variation, using deseasonalized monthly average parameters to estimate the ozone trends could smooth out the influence of seasonal fluctuations. The detection of an increase of more than 10% per year in ozone concentration at one station was particularly alarming. Effects of meteorological factors, control programmes of ozone precursors, and long-range transport on the ambient ozone level were examined in the study.     

香格里拉区域大气本底站地面臭氧浓度的变化特征

对2009年香格里拉区域大气本底站地面臭氧观测结果进行分析,研究其浓度水平、变化特征、影响因素及其区域代表性。结果表明:香格里拉站地面O₃月均值浓度在21.8~57.7 ppb,年平均值为38.0±12.1 ppb,在春季最高,平均值为54.1 ppb,在夏季最低,平均值为28.0 ppb。O₃小时均值浓度超过60 ppb的小时数占总有效小时数的6.6%,超过40 ppb的小时数占43.0%。与相近纬度中国东部地区区域大气本底站地面臭氧观测结果相比,香格里拉站体现出不同的O₃日变化和季节变化特征,具有特殊的地域特征。影响香格里拉站的气流主要来自于其西南方向,3 d的后向轨迹可追溯到孟加拉湾东北部地区。偏南的气流主要出现在夏秋季节,O₃浓度相对低,偏北的气流以冬春为主,O₃浓度相对高。     

An estimate of regional and global O3 damage from precursor NOx and VOC emissions

The results of the ozone models of EMEP and Harwell are combined with the C-R (concentration- response) functions and economic valuation recommended by the ExternE Project of the European Commission. The paper is exploratory, to assemble the available information, establish likely priority impact categories, and make recommendations for future research. Impacts on health and agriculture are evaluated. Based on the EMEP results, aggregate regional (Europe-wide) estimates of ozone damage, allocated per ton of precursor emission, are derived. Calculations on the global scale, using results from the Harwell Global Ozone Model (and the same valuation per nL/L O₃) indicate that damages outside Europe are likely to also be significant although somewhat smaller. For the EMEP Model, the numbers per ton of precursor emission are approximately the same for NO_x and for VOC. For NO_x, a value around $1875 (uncertainty range 375 to 10 000) per Mg _{NO2 equi} was found; for VOC, approximately $1100 per Mg_VOC was found. There is much uncertainty, especially in the C-R functions, and current assessments of ozone damages are, at best, order of magnitude estimates. Even though the overlap between local, regional, and global models is not clear, the results suggest that ozone damage is dominated by regional impacts.     

WATCH

Abstract

The characteristics of fine particulate pollution (PM₁₀ and PM_2.5) were measured at urban and suburban sites in Jinan during the 2008–2009 heating and non-heating seasons. The results showed that PM₁₀ and PM_2.5 pollution was quite serious, and PM mass concentration was higher during the heating season than the non-heating season. PM was the highest in the chemical factory and lowest in the development zone. The mass concentrations of PM₁₀ and PM_2.5 were linearly related, and the mass concentration ratio of PM_2.5/PM₁₀ was up to 0.59 in urban areas. PM pollution in Jinan was related to local meteorological factors: PM_2.5 mass concentration and humidity were positively correlated, and PM_2.5 mass concentration was negatively correlated with both click on the temperature and wind speed, although wind speed varied more.     

Cost-Effective Control of Ground-Level Ozone Pollution in and around Beijing

Abstract

Ground level ozone pollution has become a significant air pollution problem in Beijing. Because of the complex way in which ozone is formed, it is difficult for policy makers to identify optimal control options on a cost-effective basis. This paper identifies and assesses a range of options for addressing this problem. We apply the Ambient Least Cost Model and compare the economic costs of control options, then recommend the most effective sequence to realize pollution control at the lowest cost. The study finds that installing of Stage II gasoline vapor recovery system at Beijing’s 1446 gasoline stations would be the most cost-effective option. Overall, options to reduce ozone pollution by cutting vehicular emissions are much more cost-effective than options to “clean up” coal-fired power plants.     

区域经济重心及 COD、SO_2、TSP排放重心演变路径分析——以江苏省为例

运用重心模型，采用1996~2006年江苏省经济和环境数据，计算出各年份GDP、工业产值、COD、SO ₂和TSP排放重心坐标，揭示江苏省经济重心和环境污染排放重心变化轨迹及演变规律，以期为江苏省环境宏观战略决策及生态省建设提供理论参考。研究表明，经济重心总体上向东南方向偏移，GDP重心偏移距离为14.81 km，工业产值重心偏移距离为12.84 km；经济重心在南北方向上的偏移程度大于东西方向的偏移程度。环境污染排放重心也向东南方向偏移，COD和TSP排放重心轨迹呈现较大变化，SO2排放重心轨迹变动较小；COD排放重心偏移距离为79.26 km，SO₂排放重心偏移距离为15.73 km，TSP排放重心偏移距离为42.24 km；各污染排放重心轨迹在不同时段表现出不同特点。COD、SO₂和TSP排放重心相对于经济重心偏向于西北方向，且COD排放重心近年来明显趋向于工业产值重心；COD排放重心和TSP排放重心与经济重心存在着强正相关.     

A preliminary study of ozone trend and its impact on environment in Hong Kong

As far as the impact of air pollutants on human health being is concerned, ozone (O3) is one of the most pollutant sources, and, in particular, the ground level ozone is responsible for a variety of adverse effects on both human being and plant life. To protect the population from such adverse health effects, early information and precautions about the high ozone level need to be ascertained. In this study, statistical characteristics of ground level ozone is analyzed according to field monitoring data in mixed residential, commercial and industrial areas, e.g., Tsuen Wan area in Hong Kong. The study deals with the characteristics of hourly and daily mean ozone levels under different climatic conditions such as temperature, solar radiation (SR), wind speed (WS), and other pollutant concentration levels. The study aims to investigate the importance of meteorological factors and their impact on relevant pollutant concentration levels from a chemical aspect. Further, reasons for the spatial and temporal variation of ozone levels are discussed. All these results will provide a physical basis for accurately predicting ozone concentration in similar research.     

Annual and diurnal variations of gaseous and particulate pollutants in 31 provincial capital cities based on in situ air quality monitoring data from China National Environmental Monitoring Center

Long-term air quality data with high temporal and spatial resolutions are needed to understand some important processes affecting the air quality and corresponding environmental and health effects. The annual and diurnal variations of each criteria pollutant including PM_2.5 and PM₁₀ (particulate matter with aerodynamic diameter less than 2.5 μm and 10 μm, respectively), CO (carbon monoxide), NO₂ (nitrogen dioxide), SO₂ (sulfur dioxide) and O₃ (ozone) in 31 provincial capital cities between April 2014 and March 2015 were investigated by cluster analysis to evaluate current air pollution situations in China, and the cities were classified as severely, moderately, and slightly polluted cities according to the variations. The concentrations of air pollutants in winter months were significantly higher than those in other months with the exception of O₃, and the cities with the highest CO and SO₂ concentrations were located in northern China. The annual variation of PM_2.5 concentrations in northern cities was bimodal with comparable peaks in October 2014 and January 2015, while that in southern China was unobvious with slightly high PM_2.5 concentrations in winter months. The concentrations of particulate matter and trace gases from primary emissions (SO₂ and CO) and NO₂ were low in the afternoon (~ 16:00), while diurnal variation of O₃ concentrations was opposite to that of other pollutants with the highest values in the afternoon. The most polluted cities were mainly located in North China Plain, while slightly polluted cities mostly focus on southern China and the cities with high altitude such as Lasa. This study provides a basis for the formulation of future urban air pollution control measures in China.     

Impact of increasing atmospheric CO2 concentrations on global climate: Potential consequences and corrective measures

The increase in the concentration of CO₂ in the atmosphere is closely related to man's activities. There is much concern that this increase might be a major factor contributing to global climatic change. This review analyses the potential climatic impact of these increasing CO₂ concentrations, discusses the potential consequences of the resulting climatic changes, and presents possible solutions to the CO₂ problem.     

Tritium concentrations in the atmospheric environment at Rokkasho, Japan before the final testing of the spent nuclear fuel reprocessing plant

This study aimed at obtaining background tritium concentrations in precipitation and air at Rokkasho where the first commercial spent nuclear fuel reprocessing plant in Japan has been under construction. Tritium concentration in monthly precipitation during fiscal years 2001-2005 had a seasonal variation pattern which was high in spring and low in summer. The tritium concentration was higher than that observed at Chiba City as a whole. The seasonal peak concentration at Rokkasho was generally higher than that at Chiba City, while the baseline concentrations of both were similar. The reason for the difference may be the effect of air mass from the Asian continent which is considered to have high tritium concentration. Atmospheric tritium was operationally separated into HTO, HT and hydrocarbon (CH₃T) fractions, and the samples collected every 3 d-14 d during fiscal year 2005 were analyzed for these fractions. The HTO concentration as radioactivity in water correlated well with that in the precipitation samples. The HT concentration was the highest among the chemical forms analyzed, followed by the HTO and CH₃T concentrations. The HT and CH₃T concentrations did not have clear seasonal variation patterns. The HT concentration followed the decline previously reported by Mason and Östlund with an apparent half-life of 4.8 y. The apparent and environmental half-lives of CH₃T were estimated as 9.2 y and 36.5 y, respectively, by combining the present data with literature data. The Intergovernmental Panel on Climate Change used the atmospheric lifetime of 12 y for CH₄ to estimate global warming in its 2007 report. The longer environmental half-life of CH₃T suggested its supply from other sources than past nuclear weapon testing in the atmosphere.     

Chemical characteristics of precipitation and wet deposition of major ions in Liaozhong County of Liaoning Province,Northeast China

The chemical characteristics of precipitation were analyzed based on the chemical composition of principal ionic within acid rain（from February 2007 to January 2008）of Liaozhong Meteorological Station located in Malong Village in Liaozhong County of Northeast China,meteorological conditions on the corresponding period ground,and variation of several air pollutants concentration.The results indicated that:（1）The precipitation average pH value of all samples was4.76;the frequency of acid rain during the observation period was 70.7%;the frequency was 82.8%in summer and autumn.（2）In the chemical composition of precipitation,the primary anions were SO₄^2-and NO₃^-;the primary cations were NH₄⁺and Ca²⁺.（3）All concentration of anions was higher in summer and winter,but relatively low in spring and autumn.This showed that the relationship between regional rainfall acidification and pollution was not significant.（4）Rainwater acidity and nearly floor gaseous pollution concentration were different from each other,and pH and NO_x,CO,NO₂ and O₃concentrations showed significant negative correlation,but was not obvious with SO₂ concentration.However,the pH and alkaline pollutants,such as particulate,was positively correlative.     

Prediction of maximum daily ozone level using combined neural network and statistical characteristics

Analysis and forecasting of air quality parameters are important topics of atmospheric and environmental research today due to the health impact caused by air pollution. As one of major pollutants, ozone, especially ground level ozone, is responsible for various adverse effects on both human being and foliage. Therefore, prediction of ambient ozone levels in certain environment, especially the ground ozone level in densely urban areas, is of great importance to urban air quality and city image. To date, though several ozone prediction models have been established, there is still a need for more accurate models to develop effective warning strategies. The development of such models is difficult because the meteorological variables and the photochemical reactions involved in ozone formation are very complex. The present work aims to develop an improved neural network model, which combines the adaptive radial basis function (ARBF) network with statistical characteristics of ozone in selected specific areas, and is used to predict the daily maximum ozone concentration level. The improved method is trained and testified by hourly time series data collected at three air pollutant-monitoring stations in Hong Kong during 1999 and 2000. The simulation results demonstrate the effectiveness and the reliability of the proposed method.     

Associations among plasma metabolite levels and short-term exposure to PM2.5 and ozone in a cardiac catheterization cohort

RationaleExposure to ambient particulate matter (PM) and ozone has been associated with cardiovascular disease (CVD). However, the mechanisms linking PM and ozone exposure to CVD remain poorly understood.ObjectiveThis study explored associations between short-term exposures to PM with a diameter < 2.5 μm (PM_2.5) and ozone with plasma metabolite concentrations.Methods and resultsWe used cross-sectional data from a cardiac catheterization cohort at Duke University, North Carolina (NC), USA, accumulated between 2001 and 2007. Amino acids, acylcarnitines, ketones and total non-esterified fatty acid plasma concentrations were determined in fasting samples. Daily concentrations of PM_2.5 and ozone were obtained from a Bayesian space-time hierarchical model, matched to each patient's residential address. Ten metabolites were selected for the analysis based on quality criteria and cluster analysis. Associations between metabolites and PM_2.5 or ozone were analyzed using linear regression models adjusting for long-term trend and seasonality, calendar effects, meteorological parameters, and participant characteristics.We found delayed associations between PM_2.5 or ozone and changes in metabolite levels of the glycine-ornithine-arginine metabolic axis and incomplete fatty acid oxidation associated with mitochondrial dysfunction. The strongest association was seen for an increase of 8.1 μg/m³ in PM_2.5 with a lag of one day and decreased mean glycine concentrations (− 2.5% [95% confidence interval: − 3.8%; − 1.2%]).ConclusionsShort-term exposures to ambient PM_2.5 and ozone is associated with changes in plasma concentrations of metabolites in a cohort of cardiac catheterization patients. Our findings might help to understand the link between air pollution and cardiovascular disease.     

Carbon dioxide and climate: Comparison of one- and three-dimensional models

Calculations indicate that there may be a potential climatic problem due to the release of CO₂ from burning fossil fuels. However there is insufficient scientific evidence to predict the impact because the available models are not well enough understood and do not take into account many feedback mechanisms. Therefore, we have calculated atmospheric temperature changes versus latitude with the simpler Manabe-Wetherald radiative-convective model and compared it to the results of their general circulation model. In addition, we have determined the changes in several physical quantities, such as cloud abundance and surface albedo, required to compensate the temperature rise related to increased CO₂ concentrations.     

A model of ozone production in urban plumes

A model of rural smogs and urban plumes introduced into rural smog is developed. The single day variation of level of reactive species including ozone in rural smog in the eastern United States is simulated by mathematical modelling. Rural air masses are modelled as though they were outdoor smog chamber systems of low inital contaminant concentration to which small additional injections of contaminants, representing rural emissions, are made throughout the day. Rural smogs containing urban plumes are modelled as though they were outdoor inflatable smog chambers to which relatively large amounts of pollution material are added in the early minutes after sunrise and which are continuously diluted with material from chambers simulating rural smog. The urban plume model is specifically intended to simulate the photochemistry of parcels of air which sweep over relatively isolated cities in the eastern United States.The model runs suggest that the observed lack of urban plumes downwind of small cities is due to dilution. Additionally, the model suggests that the concentrations of both ozone and ozone precursors in rural smog have a significant effect on ozone production in urban plumes.     

Cost-Effective Control of Ground-Level Ozone Pollution in and around Beijing

Ground level ozone pollution has become a significant air pollution problem in Beijing. Because of the complex way in which ozone is formed, it is difficult for policy makers to identify optimal control options on a cost-effective basis. This paper identi-fies and assesses a range of options for addressing this problem. We apply the Ambient Least Cost Model and compare the eco-nomic costs of control options, then recommend the most effective sequence to realize pollution control at the lowest cost. The study finds that installing of Stage II gasoline vapor recovery system at Beijing’s 1446 gasoline stations would be the most cost-effective option. Overall, options to reduce ozone pollution by cutting ve-hicular emissions are much more cost-effective than options to "clean up" coal-fired power plants.     

Paradoxical ozone associations could be due to methyl nitrite from combustion of methyl ethers or esters in engine fuels

We review studies of the effects of low ambient ozone concentrations on morbidity that found a negative coefficient for ozone concentration. We call this a Paradoxical Ozone Association (POA). All studies were in regions with methyl ether in gasoline. All but one study carefully controlled for the effects of other criterion pollutants, so the phenomenon cannot be attributed to them. One was in southern California in mid-summer when ozone levels are highest. Because ozone is created by sunlight, the most plausible explanation for a POA would be an ambient pollutant that is rapidly destroyed by sunlight, such as methyl nitrite (MN). A previously published model of engine exhaust chemistry suggested methyl ether in the fuel will create MN in the exhaust. MN is known to be highly toxic, and closely related alkyl nitrites are known to induce respiratory sensitivity in humans. Support for the interpretation comes from many studies, including three linking asthma symptoms to methyl tertiary butyl ether (MTBE) and the observation that a POA has not been seen in regions without ether in gasoline. We also note that studies in southern California show a historical trend from more significant to less significant ozone-health associations. The timing of those changes is consistent with the known timing of the introduction of gasoline oxygenated with MTBE in that region.