A025-01
Enhanced secondary pollution offset reduction of primary emissions during COVID-19 lockdown in China

Monday, 7 December 2020: 19:00
Virtual
Aijun Ding, Nanjing University, Joint International Research Laboratory of Atmospheric and Earth System Sciences, School of Atmospheric Sciences, Nanjing, China, Xin Huang, Nanjing University, School of Atmospheric Sciences, Nanjing, China, Jian Gao, Chinese Research Academy of Environmental Sciences, Beijing, China, Bo Zheng, State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China, Steven J Davis, University of California Irvine, Department of Earth System Science, Irvine, CA, United States, Qiang Zhang, Tsinghua University, Beijing, China and Kebin He, Tsinghua University, School of Environment, Beijing, China
Recorded Presentation
Abstract:
To control the spread of the 2019 novel coronavirus (COVID-19), China imposed nationwide restrictions on the movement of its population (lockdown) after the Chinese New Year of 2020, leading to large reductions in economic activities and associated emissions. Despite such large decreases in primary pollution, there were nonetheless several periods of heavy haze pollution in East China, raising questions about the well-established relationship between human activities and air quality. Here, using comprehensive measurements and modeling, we show the haze during the COVID lockdown were driven by enhancements of secondary pollution. In particular, large decreases in NOx emissions from transportation increased ozone and nighttime NO3 radical formation, and these increases in atmospheric oxidizing capacity in turn facilitated the formation of secondary particulate matter. Our results, afforded by the tragic natural experiment of the COVID-19 pandemic, indicate that haze mitigation depends upon a coordinated and balanced strategy for controlling multiple pollutants.

Reference:

Huang, X., A. Ding, J. Gao, B. Zheng, D. Zhou, X. Qi, R. Tang, J. Wang, C. Ren, W. Nie, X. Chi, Z. Xu, L. Chen, Y. Li, F. Che, N. Pang, H. Wang, D. Tong, W. Qin, W. Cheng, W. Liu, Q. Fu, B. Liu, F. Chai, S.J. Davis, Q. Zhang, and K. He, Enhanced secondary pollution offset reduction of primary emissions ruing COVID-19 lockdown in China, National Science Review, nwaa137, https://doi.org/10.1093/nsr/nwaa137, 2020.

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