Contrasting trends of PM2.5 and surface-ozone concentrations in China from 2013 to 2017

Yonghong Wang; Wenkang Gao; Shuai Wang; Tao Song; Zhengyu Gong; Dongsheng Ji; Lili Wang; Zirui Liu; Guiqian Tang; Yanfeng Huo; Shili Tian; Jiayun Li; Mingge Li; Yuan Yang; Biwu Chu; Tuukka Petäjä; Veli-Matti Kerminen; Hong He; Jiming Hao; Markku Kulmala; Yuesi Wang; Yuanhang Zhang

doi:10.1093/nsr/nwaa032

Contrasting trends of PM_2.5 and surface-ozone concentrations in China from 2013 to 2017

Natl Sci Rev. 2020 Aug;7(8):1331-1339. doi: 10.1093/nsr/nwaa032. Epub 2020 Feb 28.

Authors

Yonghong Wang¹, Wenkang Gao¹, Shuai Wang², Tao Song¹, Zhengyu Gong², Dongsheng Ji¹, Lili Wang¹, Zirui Liu¹, Guiqian Tang¹, Yanfeng Huo³, Shili Tian¹, Jiayun Li¹, Mingge Li¹, Yuan Yang¹, Biwu Chu⁴, Tuukka Petäjä⁴, Veli-Matti Kerminen⁴, Hong He⁵, Jiming Hao⁶, Markku Kulmala⁴, Yuesi Wang¹, Yuanhang Zhang⁷

Affiliations

¹ State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (LAPC), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China.
² China National Environmental Monitoring Center (CNEMC), Beijing 100012, China.
³ Anhui Institute of Meteorological Sciences, Hefei 230031, China.
⁴ Institute for Atmospheric and Earth System Research, University of Helsinki, Helsinki 00014, Finland.
⁵ State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
⁶ State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
⁷ State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.

Abstract

Although much attention has been paid to investigating and controlling air pollution in China, the trends of air-pollutant concentrations on a national scale have remained unclear. Here, we quantitatively investigated the variation of air pollutants in China using long-term comprehensive data sets from 2013 to 2017, during which Chinese government made major efforts to reduce anthropogenic emission in polluted regions. Our results show a significant decreasing trend in the PM_2.5 concentration in heavily polluted regions of eastern China, with an annual decrease of ∼7% compared with measurements in 2013. The measured decreased concentrations of SO₂, NO₂ and CO (a proxy for anthropogenic volatile organic compounds) could explain a large fraction of the decreased PM_2.5 concentrations in different regions. As a consequence, the heavily polluted days decreased significantly in corresponding regions. Concentrations of organic aerosol, nitrate, sulfate, ammonium and chloride measured in urban Beijing revealed a remarkable reduction from 2013 to 2017, connecting the decreases in aerosol precursors with corresponding chemical components closely. However, surface-ozone concentrations showed increasing trends in most urban stations from 2013 to 2017, which indicates stronger photochemical pollution. The boundary-layer height in capital cities of eastern China showed no significant trends over the Beijing-Tianjin-Hebei, Yangtze River Delta and Pearl River Delta regions from 2013 to 2017, which confirmed the reduction in anthropogenic emissions. Our results demonstrated that the Chinese government was successful in the reduction of particulate matter in urban areas from 2013 to 2017, although the ozone concentration has increased significantly, suggesting a more complex mechanism of improving Chinese air quality in the future.

Keywords: China; air pollution; chemical composition; clean-air action; particulate matter; surface ozone.