Anthropogenic drivers of 2013–2017 trends in summer surface ozone in China
By Ke Li, D. J. Jacob, H. Liao, Lu Shen, Qiang Zhang, K. Bates. Proceedings of the National Academy of Sciences of the United States of America, 2018
1,390 citations recorded by the source corpus.
Significance Drastic air pollution control in China since 2013 has achieved sharp decreases in fine particulate matter (PM2.5), but ozone pollution has not improved. After removing the effect of meteorological variability, we find that surface ozone has increased in megacity clusters of China, notably Beijing and Shanghai. The increasing trend cannot be simply explained by changes in anthropogenic precursor [NOx and volatile organic compound (VOC)] emissions, particularly in North China Plain (NCP). The most important cause of the increasing ozone in NCP appears to be the decrease in PM2.5, slowing down the sink of hydroperoxy radicals and thus speeding up ozone production. Decreasing ozone in the future will require a combination of NOx and VOC emission controls to overcome the effect of decreasing PM2.5. Observations of surface ozone available from ∼1,000 sites across China for the past 5 years (2013–2017) show severe summertime pollution and regionally variable trends. We resolve the effect of meteorological variability on the ozone trends by using a multiple linear regression model. The residual of this regression shows increasing ozone trends of 1–3 ppbv a−1 in megacity clusters of eastern China that we attribute to changes in anthropogenic emissions. By contrast, ozone decreased in some areas of southern China. Anthropogenic NOx emissions in China are estimated to have decreased by 21% during 2013–2017, whereas volatile organic compounds (VOCs) emissions changed little. Decreasing NOx would increase ozone under the VOC-limited conditions thought to prevail in urban China while decreasing ozone under rural NOx-limited conditions. However, simulations with the Goddard Earth Observing System Chemical Transport Model (GEOS-Chem) indicate that a more important factor for ozone trends in the North China Plain is the ∼40% decrease of fine particulate matter (PM2.5) over the 2013–2017 period, slowing down the aerosol sink of hydroperoxy (HO2) radicals and thus stimulating ozone production.
Subfields: Atmospheric Science, Environmental Engineering
View Paper: https://www.semanticscholar.org/paper/03b587cd21477064ab72935e2e69f98e565f9933
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Citations in the corpus
- Ground-level ozone pollution in China: a synthesis of recent findings on influencing factors and impacts (2022, methodology): “19 8339–61 [119] Li K, Jacob D J, Liao H, Shen L, Zhang Q and Bates K H 2019 Anthropogenic drivers of 2013-2017 trends in summer surface ozone in China Proc.”
- Enhanced secondary pollution offset reduction of primary emissions during COVID-19 lockdown in China (2020, background): “In the BTH region, the enhancement is extremely significant because of the much higher NO x concentrations and weak incident solar radiation in northern China, which makes the NO-titration and O 3 -VOCs-NO x photochemistry more sensitive to the NO x reduction [37].”
- The Response in Air Quality to the Reduction of Chinese Economic Activities During the COVID‐19 Outbreak (2020, background): “Li et al. (2019), in their study to explain the ozoneincrease observed in China during the last years, highlight that aerosols scavenge HO2 and NOx radicals that otherwise would produce ozone, particularly during summertime.”
- Ozone Pollution: A Major Health Hazard Worldwide (2019, background): “5 in China, anthropogenic emissions of NOx have decreased substantially in most urban areas of China (a 21% nationwide reduction) from 2013 to 2017 (6).”
- Drivers of improved PM2.5 air quality in China from 2013 to 2017 (2019, background): “5 reduction has been proposed as a major mechanism of O3 increase (44).”