scholarly journals Significant increase of surface ozone at a rural site, north of eastern China

2016 ◽  
Vol 16 (6) ◽  
pp. 3969-3977 ◽  
Author(s):  
Zhiqiang Ma ◽  
Jing Xu ◽  
Weijun Quan ◽  
Ziyin Zhang ◽  
Weili Lin ◽  
...  
Keyword(s):  
Control Strategies ◽  
Average Rate ◽  
Surface Ozone ◽  
Eastern China ◽  
Rural Site ◽  
Filter Method ◽  
Ozone Pollution ◽  
The North ◽  
Emission Changes

Abstract. 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.

scholarly journals Significant increase of surface ozone at a regional background station in the eastern China

2015 ◽  
Vol 15 (21) ◽  
pp. 31951-31972 ◽  
Author(s):  
Z. Q. Ma ◽  
J. Xu ◽  
W. J. Quan ◽  
Z. Y. Zhang ◽  
W. L. Lin
Keyword(s):  
Control Strategies ◽  
Surface Ozone ◽  
Eastern China ◽  
Filter Method ◽  
Daily Maximum ◽  
Ozone Pollution ◽  
Short Term ◽  
Ozone Concentrations ◽  
Long Term Trend

Abstract. Ozone pollution has become one of the top environmental concerns in eastern China. Quantifying temporal trend of surface ozone concentrations is very meaningful to assess the impacts of the anthropogenic precursor reductions and the effects of emission control strategies. The level of surface ozone is impacted by both emissions of precursors and meteorological conditions. In order to examine the variation trend of ozone from 2003 to 2015 in Shangdianzi regional atmosphere background station, the modified KZ filter method was performed in this study to remove the influence of meteorological fluctuations on ozone concentrations. Results reveal that the short-term component, seasonal component and long-term component of ozone account for 36.4, 57.6 and 2.2 % of the total variance, respectively. The long-term trend shows that the surface daily maximum 8-h O3 has undergone a significant increase during 2003–2015, with a rate of 1.1 ppb yr−1. We find that the increase was completely resulted from the change of the emissions when the influence of the meteorological factors was eliminated. Furthermore, the variation of NO2 indicated that VOCs seemed to play more important role in the increase trend of the surface ozone.

scholarly journals Impacts of meteorology and emissions on surface ozone increases over Central Eastern China between 2003 and 2015

2018 ◽  
Author(s):  
Lei Sun ◽  
Likun Xue ◽  
Yuhang Wang ◽  
Longlei Li ◽  
Jintai Lin ◽  
...  
Keyword(s):  
Urban Areas ◽  
Control Strategies ◽  
Process Analysis ◽  
Surface Ozone ◽  
Eastern China ◽  
Meteorological Conditions ◽  
Transboundary Transport ◽  
Anthropogenic Nitrogen ◽  
Central Eastern ◽  
Emission Changes

Abstract. Recent studies have shown that surface ozone (O3) concentrations over Central Eastern China (CEC) have increased significantly during the past decade. We quantified the effects of changes in meteorological conditions and O3 precursor emissions on surface O3 levels over CEC between July 2003 and July 2015 using the GEOS-Chem model. The simulated monthly mean maximum daily 8-h average O3 concentration (MDA8 O3) in July increased by approximately 13.6 %, from 65.5 ± 7.9 ppbv (2003) to 74.4 ± 8.7 ppbv (2015), comparable to the observed results. The change in meteorology led to an increase of MDA8 O3 of 5.8 ± 3.9 ppbv over the central part of CEC, in contrast to a decrease of about −0.8 ± 3.5 ppbv over the eastern part of the region. In comparison, the MDA8 O3 over the central and eastern parts of CEC increased by 3.5 ± 1.4 ppbv and 5.6 ± 1.8 ppbv due to the increased emissions. The increase in regional averaged O3 resulting from the emission increase (4.0 ± 1.9 ppbv) was higher than that caused by meteorological changes (3.1 ± 4.9 ppbv) relative to the 2003 standard simulation, while the regions with larger O3 increases showed a higher sensitivity to meteorological conditions than to emission changes. Sensitivity tests indicate that increased levels of anthropogenic non-methane volatile organic compounds (NMVOCs) dominate the O3 increase over the eastern part of CEC, and anthropogenic nitrogen oxides (NOx) mainly increase O3 concentrations over the central and western parts, while decrease O3 in a few urban areas in the eastern part. Process analysis showed that net photochemical production and meteorological conditions (transport in particular) are two important factors that influence O3 levels over the CEC. The results of this study suggest a need to further assess the effectiveness of control strategies for O3 pollution in the context of regional meteorology, transboundary transport, and anthropogenic emission changes.

scholarly journals Spatial distribution and temporal trend of ozone pollution in China observed with the OMI satellite instrument, 2005–2017

2018 ◽  
Author(s):  
Lu Shen ◽  
Daniel J. Jacob ◽  
Xiong Liu ◽  
Guanyu Huang ◽  
Ke Li ◽  
...  
Keyword(s):  
Surface Ozone ◽  
Eastern China ◽  
Ozone Pollution ◽  
The North ◽  
The Pacific ◽  
Extreme Value Model ◽  
The Individual ◽  
Value Model ◽  
Ozone Episodes ◽  
Ozone Episode

Abstract. We use data from the new China Ministry of Ecology and Environment (MEE) network to show that OMI satellite observations of tropospheric ozone can successfully map the distribution of surface ozone pollution in China and the frequency of high-ozone episodes. After subtracting the Pacific background, OMI ozone enhancements over China can quantify mean summer afternoon surface ozone with a precision of 10.7 ppb and a spatial correlation coefficient R=0.73. Day-to-day correlations between OMI and the MEE ozone data are statistically significant but limited by noise in the individual OMI retrievals. OMI shows significantly higher values on surface ozone episode days (>82 ppb). An extreme value model can successfully predict the probability of surface ozone episodes from the daily OMI data. The 2005–2017 OMI record shows a 0.67 ppb a−1 increase in mean summer afternoon ozone in eastern China and an increasing frequency of ozone pollution episodes particularly in the north.

scholarly journals Impacts of meteorology and emissions on summertime surface ozone increases over central eastern China between 2003 and 2015

2019 ◽  
Vol 19 (3) ◽  
pp. 1455-1469 ◽  
Author(s):  
Lei Sun ◽  
Likun Xue ◽  
Yuhang Wang ◽  
Longlei Li ◽  
Jintai Lin ◽  
...  
Keyword(s):  
Urban Areas ◽  
Control Strategies ◽  
Surface Ozone ◽  
Eastern China ◽  
Meteorological Conditions ◽  
Budget Analysis ◽  
Sensitivity Tests ◽  
Anthropogenic Nitrogen ◽  
Central Eastern ◽  
Emission Changes

Abstract. Recent studies have shown that surface ozone (O3) concentrations over central eastern China (CEC) have increased significantly during the past decade. We quantified the effects of changes in meteorological conditions and O3 precursor emissions on surface O3 levels over CEC between July 2003 and July 2015 using the GEOS-Chem model. The simulated monthly mean maximum daily 8 h average O3 concentration (MDA8 O3) in July increased by approximately 13.6 %, from 65.5±7.9 ppbv (2003) to 74.4±8.7 ppbv (2015), comparable to the observed results. The change in meteorology led to an increase in MDA8 O3 of 5.8±3.9 ppbv over the central part of CEC, in contrast to a decrease of about -0.8±3.5 ppbv over the eastern part of the region. In comparison, the MDA8 O3 over the central and eastern parts of CEC increased by 3.5±1.4 and 5.6±1.8 ppbv due to the increased emissions. The increase in averaged O3 in the CEC region resulting from the emission increase (4.0±1.9 ppbv) was higher than that caused by meteorological changes (3.1±4.9 ppbv) relative to the 2003 standard simulation, while the regions with larger O3 increases showed a higher sensitivity to meteorological conditions than to emission changes. Sensitivity tests indicate that increased levels of anthropogenic non-methane volatile organic compounds (NMVOCs) dominate the O3 increase over the eastern part of CEC, and anthropogenic nitrogen oxides (NOx) mainly increase MDA8 O3 over the central and western parts and decrease O3 in a few urban areas in the eastern part. Budget analysis showed that net photochemical production and meteorological conditions (transport in particular) are two important factors that influence O3 levels over the CEC. The results of this study suggest a need to further assess the effectiveness of control strategies for O3 pollution in the context of regional meteorology and anthropogenic emission changes.

scholarly journals Increases in surface ozone pollution in China from 2013 to 2019: anthropogenic and meteorological influences

2020 ◽  
Vol 20 (19) ◽  
pp. 11423-11433
Author(s):  
Ke Li ◽  
Daniel J. Jacob ◽  
Lu Shen ◽  
Xiao Lu ◽  
Isabelle De Smedt ◽  
...  
Keyword(s):  
Dominant Role ◽  
Action Plan ◽  
Surface Ozone ◽  
Fine Particulate Matter ◽  
Multiple Linear Regression Model ◽  
Phase 2 ◽  
Ozone Pollution ◽  
The North ◽  
Clean Air ◽  
June July

Abstract. Surface ozone data from the Chinese Ministry of Ecology and Environment (MEE) network show sustained increases across the country over the 2013–2019 period. Despite Phase 2 of the Clean Air Action Plan targeting ozone pollution, ozone was higher in 2018–2019 than in previous years. The mean summer 2013–2019 trend in maximum 8 h average (MDA8) ozone was 1.9 ppb a−1 (p<0.01) across China and 3.3 ppb a−1 (p<0.01) over the North China Plain (NCP). Fitting ozone to meteorological variables with a multiple linear regression model shows that meteorology played a significant but not dominant role in the 2013–2019 ozone trend, contributing 0.70 ppb a−1 (p<0.01) across China and 1.4 ppb a−1 (p=0.02) over the NCP. Rising June–July temperatures over the NCP were the main meteorological driver, particularly in recent years (2017–2019), and were associated with increased foehn winds. NCP data for 2017–2019 show a 15 % decrease in fine particulate matter (PM2.5) that may be driving the continued anthropogenic increase in ozone, as well as unmitigated emissions of volatile organic compounds (VOCs). VOC emission reductions, as targeted by Phase 2 of the Chinese Clean Air Action Plan, are needed to reverse the increase in ozone.

scholarly journals Measurements of ozone and its precursors in Beijing during summertime: impact of urban plumes on ozone pollution in downwind rural areas

2011 ◽  
Vol 11 (6) ◽  
pp. 17337-17373 ◽  
Author(s):  
J. Xu ◽  
J. Z. Ma ◽  
X. L. Zhang ◽  
X. B. Xu ◽  
X. F. Xu ◽  
...  
Keyword(s):  
Rural Areas ◽  
Surface Ozone ◽  
Regional Scale ◽  
Rural Site ◽  
Traffic Density ◽  
Prevailing Wind ◽  
Ozone Pollution ◽  
Rural Sites ◽  
Urban And Rural Areas ◽  
Urban Plumes

Abstract. Sea-land and mount-valley circulations are the dominant mesoscale synoptic systems affecting the Beijing area during summertime. Under the influence of these two circulations, the prevailing wind is southwesterly from afternoon to midnight, and then changes to northeasterly till forenoon. In this study, surface ozone (O3), carbon monoxide (CO), nitric oxide (NO), nitrogen dioxide (NO2), nitrogen oxide (NOx) and non-methane hydrocarbons (NMHCs) were measured at four sites located along the route of prevailing wind, including two upwind urban sites (Fengtai (FT) and Baolian (BL)), an upwind suburban site (Shunyi (SY)) and a downwind rural site (Shangdianzi (SDZ)) during 20 June–16 September 2007. The purpose is to improve our understanding of ozone photochemistry in urban and rural areas of Beijing and the influence of urban plumes on ozone pollution in downwind rural areas. It is found that ozone pollution was synchronism in the urban and rural areas of Beijing, coinciding with the regional-scale synoptic processes. Due to the high traffic density and local emissions, the average levels of reactive gases NOx and NMHCs at the non-rural sites were much higher than those at SDZ. The level of long-lived gas CO at SDZ was comparable to and slightly lower than it was at other sites. The daily-averaged ozone concentration at SDZ was much higher than at other sites due to weak titration. Ranking by OH loss rate coefficient (LOH), alkenes played a dominant role in total NMHCs reactivity at both urban and rural sites during the experiment, accounting for 48.6 % and 52.1 % of total LOH, respectively. The NMHCs data were also used to estimate the ozone potential formation (OFP) in Beijing. The leading contributors to ozone formation were aromatics at both urban and rural sites during the experiment, which accounts for 55.5 % and 49.4 % of total OFP, respectively. The ozone peak values are found to lag behind one site after another along the route of prevailing wind from SW to NE. Intersection analyses of trace gases reveal that polluted air masses arriving at SDZ were more aged with both higher O3 and Ox concentrations than those at BL. The results indicate that urban plume can transport not only O3 but its precursors, the latter leading more photochemical O3 production when being mixed with background atmosphere in the downwind rural area.

scholarly journals Contributions of pollutants from North China Plain to surface ozone at the Shangdianzi GAW Station

2008 ◽  
Vol 8 (19) ◽  
pp. 5889-5898 ◽  
Author(s):  
W. Lin ◽  
X. Xu ◽  
X. Zhang ◽  
J. Tang
Keyword(s):  
North China Plain ◽  
North China ◽  
Surface Ozone ◽  
Surface Wind ◽  
Ozone Pollution ◽  
Ancillary Data ◽  
Ozone Concentrations ◽  
The North ◽  
The North China Plain ◽  
Autumn And Winter

Abstract. Regional ozone pollution has become one of the top environmental concerns in China, especially in those economically vibrant and densely populated regions, such as North China region including Beijing. To address this issue, surface ozone and ancillary data over the period 2004–2006 from the Shangdianzi Regional Background Station in north China were analyzed. Due to the suitable location and valley topography of the site, transport of pollutants from the North China Plain was easily observed and quantified according to surface wind directions. Regional (polluted) and background (clean) ozone concentrations were obtained by detailed statistic analysis. Contribution of pollutants from North China Plain to surface ozone at SDZ was estimated by comparing ozone concentrations observed under SW wind conditions and that under NE wind conditions. The average daily accumulated ozone contribution was estimated to be 240 ppb·hr. The average regional contributions to surface ozone at SDZ from the North China Plain were 21.8 ppb for the whole year, and 19.2, 28.9, 25.0, and 10.0 ppb for spring, summer, autumn, and winter, respectively. The strong ozone contribution in summer led to disappearance of the spring ozone maximum phenomenon at SDZ under winds other than from the NNW to E sectors. The emissions of nitrogen oxide in the North China plain cause a decrease in ozone concentrations in winter.

scholarly journals Local and synoptic meteorological influences on daily variability in summertime surface ozone in eastern China

2020 ◽  
Vol 20 (1) ◽  
pp. 203-222 ◽  
Author(s):  
Han Han ◽  
Jane Liu ◽  
Lei Shu ◽  
Tijian Wang ◽  
Huiling Yuan
Keyword(s):  
Surface Ozone ◽  
Eastern China ◽  
River Delta ◽  
Daily Maximum ◽  
Ozone Pollution ◽  
Study Region ◽  
Synoptic Weather ◽  
Daily Variability ◽  
Influential Variable ◽  
The Impact

Abstract. Ozone pollution in China is influenced by meteorological processes on multiple scales. Using regression analysis and weather classification, we statistically assess the impacts of local and synoptic meteorology on daily variability in surface ozone in eastern China in summer during 2013–2018. In this period, summertime surface ozone in eastern China (20–42∘ N, 110–130∘ E) is among the highest in the world, with regional means of 73.1 and 114.7 µg m−3, respectively, in daily mean and daily maximum 8 h average. Through developing a multiple linear regression (MLR) model driven by local and synoptic weather factors, we establish a quantitative linkage between the daily mean ozone concentrations and meteorology in the study region. The meteorology described by the MLR can explain ∼43 % of the daily variability in summertime surface ozone across eastern China. Among local meteorological factors, relative humidity is the most influential variable in the center and south of eastern China, including the Yangtze River Delta and the Pearl River Delta regions, while temperature is the most influential variable in the north, covering the Beijing–Tianjin–Hebei region. To further examine the synoptic influence of weather conditions explicitly, six predominant synoptic weather patterns (SWPs) over eastern China in summer are objectively identified using the self-organizing map clustering technique. The six SWPs are formed under the integral influence of the East Asian summer monsoon, the western Pacific subtropical high, the Meiyu front, and the typhoon activities. On average, regionally, two SWPs bring about positive ozone anomalies (1.1 µg m−3 or 1.7 % and 2.7 µg m−3 or 4.6 %), when eastern China is under a weak cyclone system or under the prevailing southerly wind. The impact of SWPs on the daily variability in surface ozone varies largely within eastern China. The maximum impact can reach ±8 µg m−3 or ±16 % of the daily mean in some areas. A combination of the regression and the clustering approaches suggests a strong performance of the MLR in predicting the sensitivity of surface ozone in eastern China to the variation of synoptic weather. Our assessment highlights the importance of meteorology in modulating ozone pollution over China.

Patterns in data of extreme droughts/floods and harvest grades derived from historical documents in eastern China during 801–1910

2020 ◽  
Author(s):  
Zhixin Hao
Keyword(s):  
Crop Production ◽  
Eastern China ◽  
Regional Scale ◽  
Extreme Drought ◽  
Historical Documents ◽  
The North ◽  
Historical Factors ◽  
Extreme Flood ◽  
The Impact

&lt;p&gt;In China, historical documents record a large quantity of information related to climate change and grain harvest. This information can help to explore the impacts of extreme drought or flood on crop production, which can provide implications for the adaptation of agriculture to higher-probability extreme climate in the context of global warming. In this paper, reported extreme drought/flood chronologies and reconstructed grain harvest series derived from historical documents were adopted in order to investigate the association between the reported frequency of extreme drought/flood in eastern China and reconstructed poor harvests during 801&amp;#8211;1910. The results show that extreme droughts were reported more often in 801&amp;#8211;870, 1031&amp;#8211;1230, 1481&amp;#8211;1530, and 1581&amp;#8211;1650 over the whole of eastern China. On a regional scale, extreme droughts were reported more often in 1031&amp;#8211;1100, 1441&amp;#8211;1490, 1601&amp;#8211;1650, and 1831&amp;#8211;1880 in the North China Plain, 801&amp;#8211;870, 1031&amp;#8211;1120, 1161&amp;#8211;1220, and 1471&amp;#8211;1530 in Jianghuai, and 991&amp;#8211;1040, 1091&amp;#8211;1150, 1171&amp;#8211;1230, 1411&amp;#8211;1470, and 1481&amp;#8211;1530 in Jiangnan. The grain harvest was reconstructed to be generally poor in 801&amp;#8211;940, 1251&amp;#8211;1650, and 1841&amp;#8211;1910, but the reconstructed harvests were bumper in 951&amp;#8211;1250 and 1651&amp;#8211;1840, approximately. During the entire period from 801 to 1910, the frequency of reporting of extreme droughts in any subregion of eastern China was significantly associated over the long term with lower reconstructed harvests. The association between reported frequency of extreme floods and reconstructed low harvests appeared to be much weaker, while reconstructed harvest was much worse when extreme drought and extreme flood in different subregions were reported in the same year. The association between reconstructed poor harvests and reported frequency of regional extreme droughts was weak during the warm epoch of 920&amp;#8211;1300 but strong during the cold epoch of 1310&amp;#8211;1880, which could imply that a warm climate could weaken the impact of extreme drought on poor harvests; yet other historical factors may also contribute to these different patterns extracted from the two datasets.&lt;/p&gt;

scholarly journals Long-term trends of surface ozone and its influencing factors at the Mt. Waliguan GAW station, China, Part 2: Variation mechanism and links to some climate indices

2017 ◽  
Author(s):  
Wanyun Xu ◽  
Xiaobin Xu ◽  
Meiyun Lin ◽  
Weili Lin ◽  
Jie Tang ◽  
...  
Keyword(s):  
Southeast Asia ◽  
Trajectory Analysis ◽  
Surface Ozone ◽  
Eastern China ◽  
Sunspot Cycle ◽  
Anthropogenic Emissions ◽  
Climate Indices ◽  
Air Masses ◽  
Long Term Trends

Abstract. Interannual variability and long-term trends of tropospheric ozone are both of environmental and climate concerns. Ozone measured at Mt. Waliguan Observatory (WLG, 3816 m asl) on the Tibetan Plateau over the period 19947ndash;2013 has increased significantly by 0.2–0.3 ppbv year-1 during spring and autumn, but shows a much smaller trend in winter and no significant trend in summer. Here we explore the factors driving the observed ozone changes at WLG using backward trajectory analysis, chemistry-climate model hindcast simulations (GFDL-AM3), a trajectory-mapped ozonesonde dataset and various climate indices. A stratospheric ozone tracer implemented in GFDL-AM3 indicates that stratosphere-to-troposphere transport (STT) can explain ~ 70 % of the observed springtime ozone increase at WLG, consistent with an increase in the NW air mass frequency inferred from the trajectory analysis. Enhanced STT associated with the strengthening of the mid-latitude jet stream contributes to the observed high-ozone anomalies at WLG during the springs of 1999 and 2012. During autumn, observations at WLG are more heavily influenced by polluted air masses originated from Southeast Asia than in the other seasons. Rising Asian anthropogenic emissions of ozone precursors is the key driver of increasing autumnal ozone observed at WLG, as supported by the GFDL-AM3 model with time-varying emissions, which captures the observed ozone increase (0.26 ± 0.11 ppbv year-1). AM3 simulates a greater ozone increase of 0.38 ± 0.11 ppbv year-1 at WLG in autumn under conditions with strong transport from Southeast Asia and shows no significant ozone trend in autumn when anthropogenic emissions are held constant in time. During summer, WLG is mostly influenced by easterly air masses but these trajectories do not extend to the polluted regions of eastern China and have decreased significantly over the last two decades, which likely explains why summertime ozone measured at WLG shows no significant trend despite ozone increases in Eastern China. Analysis of the Trajectory-mapped Ozonesonde dataset for the Stratosphere and Troposphere (TOST) and trajectory residence time reveals increases in direct ozone transport from the eastern sector during autumn, which adds to the autumnal ozone increase. We further examine the links of ozone variability at WLG to the QBO, the North Atlantic Oscillation (NAO), the East Asian summer monsoon (EASM) and the sunspot cycle. Our results suggest that the 2–3 year, 3–7 year and 11 year periodicities are linked to QBO, EASMI and NAO and the sunspot cycle, respectively. A multivariate regression analysis is performed to quantify the relative contributions of various factors to surface ozone concentrations at WLG. Through an observational and modelling analysis, this study demonstrates the complex relationships between surface ozone at remote locations and its dynamical and chemical influencing factors.

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