scholarly journals Widespread and Persistent Ozone Pollution in Eastern China

2016 ◽  
Author(s):  
Guohui Li ◽  
Naifang Bei ◽  
Junji Cao ◽  
Jiarui Wu ◽  
Xin Long ◽  
...  
Keyword(s):  
Control Strategies ◽  
Action Plan ◽  
Eastern China ◽  
Pollution Prevention ◽  
Temporal Variations ◽  
Anthropogenic Sources ◽  
Daily Maximum ◽  
Ozone Pollution ◽  
Near Surface ◽  
Model Studies

Abstract. Rapid growth of industrialization, transportation, and urbanization has caused increasing emissions of ozone (O3) precursors recently, enhancing the O3 formation in Eastern China. We show here that Eastern China has experienced widespread and persistent O3 pollution from April to September in 2015 based on the O3 observations in 223 cities. The observed maximum 1-h O3 concentrations exceed 200 μg m−3 in almost all the cities, 400 μg m−3 in more than 25 % of the cities, and even 800 μg m−3 in six cities in Eastern China. The average daily maximum 1-h O3 concentrations are more than 160 μg m−3 in 45 % of the cities, and the 1-h O3 concentrations of 200 μg m−3 have been exceeded on over 10 % of days from April to September in 129 cities. A widespread and severe O3 pollution episode from 22 to 28 May 2015 in Eastern China has been simulated using the WRF-CHEM model to evaluate the O3 contribution of biogenic and various anthropogenic sources. The model generally performs reasonably well in simulating the temporal variations and spatial distributions of near-surface O3 concentrations. Using the factor separate approach, sensitivity studies have indicated that the industry source plays the most important role in the O3 formation, and constitutes the culprit of the severe O3 pollution in Eastern China. The transportation source contributes considerably to the O3 formation, and the O3 contribution of the residential source is not significant generally. The biogenic source provides a background O3 source, and also plays an important role in the south of Eastern China. Further model studies are needed to comprehensively investigate O3 formation for supporting the design and implementation of O3 control strategies, considering rapid changes of emissions inventories and photolysis caused by the "Atmospheric Pollution Prevention and Control Action Plan", released by the Chinese State Council in 2013.

scholarly journals Widespread and persistent ozone pollution in eastern China during the non-winter season of 2015: observations and source attributions

2017 ◽  
Vol 17 (4) ◽  
pp. 2759-2774 ◽  
Author(s):  
Guohui Li ◽  
Naifang Bei ◽  
Junji Cao ◽  
Jiarui Wu ◽  
Xin Long ◽  
...  
Keyword(s):  
Control Strategies ◽  
Action Plan ◽  
Eastern China ◽  
Winter Season ◽  
Pollution Prevention ◽  
Temporal Variations ◽  
Anthropogenic Sources ◽  
Daily Maximum ◽  
Ozone Pollution ◽  
Near Surface

Abstract. Rapid growth of industrialization, transportation, and urbanization has caused increasing emissions of ozone (O3) precursors recently, enhancing the O3 formation in eastern China. We show here that eastern China has experienced widespread and persistent O3 pollution from April to September 2015 based on the O3 observations in 223 cities. The observed maximum 1 h O3 concentrations exceed 200 µg m−3 in almost all the cities, 400 µg m−3 in more than 25 % of the cities, and even 800 µg m−3 in six cities in eastern China. The average daily maximum 1 h O3 concentrations are more than 160 µg m−3 in 45 % of the cities, and the 1 h O3 concentrations of 200 µg m−3 have been exceeded on over 10 % of days from April to September in 129 cities. Analyses of pollutant observations from 2013 to 2015 have shown that the concentrations of CO, SO2, NO2, and PM2.5 from April to September in eastern China have considerably decreased, but the O3 concentrations have increased by 9.9 %. A widespread and severe O3 pollution episode from 22 to 28 May 2015 in eastern China has been simulated using the Weather Research and Forecasting model coupled to chemistry (WRF-CHEM) to evaluate the O3 contribution of biogenic and various anthropogenic sources. The model generally performs reasonably well in simulating the temporal variations and spatial distributions of near-surface O3 concentrations. Using the factor separation approach, sensitivity studies have indicated that the industry source plays the most important role in the O3 formation and constitutes the culprit of the severe O3 pollution in eastern China. The transportation source contributes considerably to the O3 formation, and the O3 contribution of the residential source is not significant generally. The biogenic source provides a background O3 source, and also plays an important role in the south of eastern China. Further model studies are needed to comprehensively investigate O3 formation for supporting the design and implementation of O3 control strategies, considering rapid changes of emission inventories and photolysis caused by the Atmospheric Pollution Prevention and Control Action Plan released by the Chinese State Council in 2013.

scholarly journals Summertime ozone formation in Xi'an and surrounding areas, China

2015 ◽  
Vol 15 (21) ◽  
pp. 30563-30608 ◽  
Author(s):  
T. Feng ◽  
N. Bei ◽  
R. Huang ◽  
J. Cao ◽  
Q. Zhang ◽  
...  
Keyword(s):  
Control Strategies ◽  
Surface Wind ◽  
Temporal Variations ◽  
Anthropogenic Sources ◽  
Anthropogenic Emissions ◽  
Near Surface ◽  
Production Regime ◽  
High Concentrations ◽  
Surrounding Areas ◽  
Surface O3

Abstract. In the study, the ozone (O3) formation is investigated in Xi'an and surrounding areas, China using the WRF-CHEM model during the period from 22 to 24 August 2013 corresponding to a heavy air pollution episode with high concentrations of O3 and PM2.5 (particulate matter with aerodynamic diameter less than 2.5 μm). The WRF-CHEM model generally performs well in simulating the surface temperature and relative humidity compared to the observations and also reasonably reproduces the observed temporal variations of the surface wind speed and direction. The convergence formed in Xi'an and surrounding areas is favorable for the accumulation of pollutants, causing high concentrations of O3 and PM2.5. In general, the calculated spatial patterns and temporal variations of near-surface O3 and PM2.5 are consistent well with the measurement at the ambient monitoring stations. The simulated daily mass concentrations of aerosol constituents, including sulfate, nitrate, ammonium, elemental and organic carbon, are also in good agreement with the filter measurements. High aerosol concentrations in Xi'an and surrounding areas significantly decrease the photolysis frequencies and can reduce near-surface O3 concentrations by more than 50 μg m−3 (around 25 ppb) on average. Sensitivity studies show that the O3 production regime in Xi'an and surrounding areas is complicated, varying from NOx to VOC-sensitive chemistry. The industry emissions contribute the most to the O3 concentrations compared to the natural and other anthropogenic sources, but still do not play a determined role in the O3 formation. The complicated O3 production regime and high aerosol levels constitute a dilemma for O3 control strategies in Xi'an and surrounding areas. In the condition with high O3 and PM2.5 concentrations, decreasing various anthropogenic emissions cannot efficiently mitigate the O3 pollution, and a 50 % reduction of all the anthropogenic emissions only decreases near-surface O3 concentrations by less than 14 % during daytime. Further studies need to be performed for O3 control strategies considering manifest changes of the emission inventory and uncertainties of meteorological field simulations.

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 Long-term trends and drivers of aerosol pH in eastern China

2021 ◽  
Author(s):  
Min Zhou ◽  
Guangjie Zheng ◽  
Hongli Wang ◽  
Liping Qiao ◽  
Shuhui Zhu ◽  
...  
Keyword(s):  
Air Pollution ◽  
Prevention And Control ◽  
Action Plan ◽  
Health Effect ◽  
Eastern China ◽  
Pollution Prevention ◽  
Control Action ◽  
Haze Pollution ◽  
Pollution Prevention And Control ◽  
And Control

Abstract. Aerosol acidity plays a key role in regulating the chemistry and toxicity of atmospheric aerosol particles. The trend of aerosol pH and its drivers are crucial in understanding the multiphase formation pathways of aerosols. Here, we reported the first trend analysis of aerosol pH from 2011 to 2019 in eastern China. The implementation of the Air Pollution Prevention and Control Action Plan leads to −35.8 %, −37.6 %, −9.6 %, −81.0 % and 1.2 % changes of PM2.5, SO42−, NHx, NVCs and NO3− in YRD during this period. Different from the fast changes of aerosol compositions due to the implementation of the Air Pollution Prevention and Control Action Plan, aerosol pH shows a moderate change of −0.24 unit over the 9 years. Besides the multiphase buffer effect, the opposite effects of SO42− and non-volatile cations changes play key roles in determining the moderate pH trend, contributing to a change of +0.38 and −0.35 unit, respectively. Seasonal variations in aerosol pH were mainly driven by the temperature, while the diurnal variations were driven by both temperature and relative humidity. In the future, SO2, NOx and NH3 emissions are expected to be further reduced by 86.9 %, 74.9 % and 41.7 % in 2050 according to the best health effect pollution control scenario (SSP1-26-BHE). The corresponding aerosol pH in eastern China is estimated to increase by ~0.9, resulting in 8 % more NO3− and 35 % less NH4+ partitioning/formation in the aerosol phase, which suggests a largely reduced benefit of NH3 and NOx emission control in mitigating haze pollution in eastern China.

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.

scholarly journals Secondary organic aerosol enhanced by increasing atmospheric oxidizing capacity in Beijing-Tianjin-Hebei (BTH), China

2019 ◽  
Author(s):  
Tian Feng ◽  
Shuyu Zhao ◽  
Naifang Bei ◽  
Jiarui Wu ◽  
Suixin Liu ◽  
...  
Keyword(s):  
Air Pollution ◽  
Secondary Organic Aerosol ◽  
Action Plan ◽  
Spatial Relationship ◽  
Pollution Prevention ◽  
Organic Aerosol ◽  
Temporal Variations ◽  
Sensitivity Studies ◽  
Distribution Studies ◽  
And Control

Abstract. The implementation of the Air Pollution Prevention and Control Action Plan in China since 2013 has profoundly altered the ambient pollutants in the Beijing-Tianjin-Hebei region (BTH). Here we show observations of substantially increased O3 concentration (about 30 %) and a remarkable increase in the ratio of organic carbon (OC) to elemental carbon (EC) in BTH during the autumn from 2013 to 2015, revealing an enhancement in atmospheric oxidizing capacity (AOC) and secondary organic aerosol (SOA) formation. To explore the impacts of increasing AOC on the SOA formation, a severe air pollution episode from 3 to 8 October 2015 with high O3 and PM2.5 concentrations is simulated using the WRF-Chem model. The model performs reasonably well in simulating the spatial distributions of PM2.5 and O3 concentrations over BTH and the temporal variations of PM2.5, O3, NO2, OC, and EC concentrations in Beijing compared to measurements. Sensitivity studies show that the change in AOC substantially influences the SOA formation in BTH. A sensitivity case characterized by a 31 % O3 decrease (or 36 % OH decrease) reduces the SOA level by about 30 % and the SOA fraction in total organic aerosol by 17 % (from 0.52 to 0.43). Spatially, the SOA decrease caused by reduced AOC is ubiquitous in BTH, but the spatial relationship between SOA concentrations and the AOC is dependent on the SOA precursor distribution. Studies on SOA formation pathways further show that, when the AOC is reduced, the SOA from oxidation, partitioning of semi-volatile POA and co-emitted intermediate volatile organic compounds (VOCs) decreases remarkably, followed by those from anthropogenic and biogenic VOCs. Meanwhile, the SOA decrease in the irreversible uptake of glyoxal and methylglyoxal on aerosol surfaces is negligible.

scholarly journals Secondary organic aerosol enhanced by increasing atmospheric oxidizing capacity in Beijing–Tianjin–Hebei (BTH), China

2019 ◽  
Vol 19 (11) ◽  
pp. 7429-7443 ◽  
Author(s):  
Tian Feng ◽  
Shuyu Zhao ◽  
Naifang Bei ◽  
Jiarui Wu ◽  
Suixin Liu ◽  
...  
Keyword(s):  
Air Pollution ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Secondary Organic Aerosol ◽  
Action Plan ◽  
Spatial Relationship ◽  
Pollution Prevention ◽  
Organic Aerosol ◽  
Temporal Variations ◽  
Volatile Organic

Abstract. The implementation of the Air Pollution Prevention and Control Action Plan in China since 2013 has profoundly altered the ambient pollutants in the Beijing–Tianjin–Hebei (BTH) region. Here we show observations of substantially increased O3 concentrations (about 30 %) and a remarkable increase in the ratio of organic carbon (OC) to elemental carbon (EC) in BTH during the autumn from 2013 to 2015, revealing an enhancement in atmospheric oxidizing capacity (AOC) and secondary organic aerosol (SOA) formation. To explore the impacts of increasing AOC on the SOA formation, a severe air pollution episode from 3 to 8 October 2015 with high O3 and PM2.5 concentrations is simulated using the WRF-Chem model. The model performs reasonably well in simulating the spatial distributions of PM2.5 and O3 concentrations over BTH and the temporal variations in PM2.5, O3, NO2, OC, and EC concentrations in Beijing compared to measurements. Sensitivity studies show that the change in AOC substantially influences the SOA formation in BTH. A sensitivity case characterized by a 31 % O3 decrease (or 36 % OH decrease) reduces the SOA level by about 30 % and the SOA fraction in total organic aerosol by 17 % (from 0.52 to 0.43, dimensionless). Spatially, the SOA decrease caused by reduced AOC is ubiquitous in BTH, but the spatial relationship between SOA concentrations and the AOC is dependent on the SOA precursor distribution. Studies on SOA formation pathways further show that when the AOC is reduced, the SOA from oxidation and partitioning of semivolatile primary organic aerosol (POA) and co-emitted intermediate volatile organic compounds (IVOCs) decreases remarkably, followed by those from anthropogenic and biogenic volatile organic compounds (VOCs). Meanwhile, the SOA decrease in the irreversible uptake of glyoxal and methylglyoxal on the aerosol surfaces is negligible.

scholarly journals Impacts of biogenic and anthropogenic emissions on summertime ozone formation in the Guanzhong Basin, China

2018 ◽  
Vol 18 (10) ◽  
pp. 7489-7507 ◽  
Author(s):  
Nan Li ◽  
Qingyang He ◽  
Jim Greenberg ◽  
Alex Guenther ◽  
Jingyi Li ◽  
...  
Keyword(s):  
Urban Areas ◽  
Control Strategies ◽  
Anthropogenic Sources ◽  
Air Pollution Control ◽  
Near Surface ◽  
Source Contributions ◽  
Surface Measurements ◽  
Individual Source ◽  
Guanzhong Basin ◽  
The Impact

Abstract. This study is the first attempt to understand the synergistic impact of anthropogenic and biogenic emissions on summertime ozone (O3) formation in the Guanzhong (GZ) Basin where Xi'an, the oldest and the most populous city (with a population of 9 million) in northwestern China, is located. Month-long (August 2011) WRF-Chem simulations with different sensitivity experiments were conducted and compared with near-surface measurements. Biogenic volatile organic compounds (VOCs) concentrations was characterized from six surface sites among the Qinling Mountains, and urban air composition was measured in Xi'an city at a tower 100 ma.s. The WRF-Chem control experiment reasonably reproduced the magnitudes and variations of observed O3, VOCs, NOx, PM2.5, and meteorological parameters, with normalized mean biases for each parameter within ±21 %. Subsequent analysis employed the factor separation approach (FSA) to quantitatively disentangle the pure and synergistic impacts of anthropogenic and/or biogenic sources on summertime O3 formation. The impact of anthropogenic sources alone was found to be dominant for O3 formation. Although anthropogenic particles reduced NO2 photolysis by up to 60 %, the anthropogenic sources contributed 19.1 ppb O3 formation on average for urban Xi'an. The abundant biogenic VOCs from the nearby forests promoted O3 formation in urban areas by interacting with the anthropogenic NOx. The calculated synergistic contribution (from both biogenic and anthropogenic sources) was up to 14.4 ppb in urban Xi'an, peaking in the afternoon. Our study reveals that the synergistic impact of individual source contributions to O3 formation should be considered in the formation of air pollution control strategies, especially for big cities in the vicinity of forests.

Impacts of Stratospheric Intrusion on Surface Ozone over Eastern China

2020 ◽  
Author(s):  
Wuke Wang
Keyword(s):  
Yangtze River ◽  
Surface Ozone ◽  
Eastern China ◽  
Yangtze River Delta ◽  
River Delta ◽  
Anthropogenic Sources ◽  
The Yangtze River ◽  
Ozone Pollution ◽  
Stratospheric Intrusion ◽  
The Yangtze River Delta

<p><span>Ozone pollution is currently a serious environmental issue in China. Most of studies have attributed the surface ozone pollution over China to the strong photochemical production from anthropogenic sources. As another important source of tropospheric ozone, the stratospheric intrusion (SI), however, has been less concerned. This study investigates the SI events over the Yangtze River Delta in eastern China using the newest ERA5 (the fifth generation of ECMWF atmospheric reanalysis) meteorological and ozone data, the In-service Aircraft for a Global Observing System (IAGOS) ozone profiles and the station-based ground-level ozone measurements. Results indicate that SI plays important roles in spring and summer ozone pollution episodes over the Yangtze River Delta, eastern China. Based on CAM-Chem (the Community Atmosphere Model with Chemistry) and LPDM (Lagrangian Particle Dispersion Modeling) model simulations, we found that deep SIs contribute ~15 ppbv in spring and ~10 ppbv in summer to surface ozone variations in eastern China. A deep SI event occurred in 2018 spring associated with a strong horizontal-trough, which brought ozone-rich air from the stratosphere to the troposphere and resulted in severe surface ozone pollution over the Yangtze River Delta. From 7-year statistics, we found that strong SI events during summer are associated with a cyclonic valley between the South Asian High and the Subtropical High, accompanied by downward fast transport of ozone from the stratosphere to the troposphere. Our results provide important information for surface ozone prediction and control in eastern China.</span></p>

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