| Title: | Anthropogenic drivers of 2013-2017 trends in summer surface ozone in China |
| Author(s): | Li K; Jacob DJ; Liao H; Shen L; Zhang Q; Bates KH; |
| Address: | "Harvard-NUIST Joint Laboratory for Air Quality and Climate, Nanjing University of Information Science and Technology, 210044 Nanjing, China. John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138. John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138; djacob@fas.harvard.edu hongliao@nuist.edu.cn. Harvard-NUIST Joint Laboratory for Air Quality and Climate, Nanjing University of Information Science and Technology, 210044 Nanjing, China; djacob@fas.harvard.edu hongliao@nuist.edu.cn. Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, 210044 Nanjing, China. Department of Earth System Science, Tsinghua University, 100084 Beijing, China" |
| ISSN/ISBN: | 1091-6490 (Electronic) 0027-8424 (Print) 0027-8424 (Linking) |
| Abstract: | "Observations of surface ozone available from approximately 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 NO(x) emissions in China are estimated to have decreased by 21% during 2013-2017, whereas volatile organic compounds (VOCs) emissions changed little. Decreasing NO(x) would increase ozone under the VOC-limited conditions thought to prevail in urban China while decreasing ozone under rural NO(x)-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 approximately 40% decrease of fine particulate matter (PM(2.5)) over the 2013-2017 period, slowing down the aerosol sink of hydroperoxy (HO(2)) radicals and thus stimulating ozone production" |
| Keywords: | Air/*analysis Air Pollutants/*analysis Air Pollution China Humans Ozone/*analysis *Urban Renewal Volatile Organic Compounds/*analysis aerosol chemistry air quality emission reductions surface ozone; |
| Notes: | "MedlineLi, Ke Jacob, Daniel J Liao, Hong Shen, Lu Zhang, Qiang Bates, Kelvin H eng Research Support, Non-U.S. Gov't 2019/01/02 Proc Natl Acad Sci U S A. 2019 Jan 8; 116(2):422-427. doi: 10.1073/pnas.1812168116. Epub 2018 Dec 31" |
