Diverse response of surface ozone to COVID-19 lockdown in China

Yiming Liu; Tao Wang; Trissevgeni Stavrakou; Nellie Elguindi; Thierno Doumbia; Claire Granier; Idir Bouarar; Benjamin Gaubert; Guy P. Brasseur

doi:10.1016/j.scitotenv.2021.147739

paper

Diverse response of surface ozone to COVID-19 lockdown in China

arXiv:2008.10851 · doi:10.1016/j.scitotenv.2021.147739

Abstract

Ozone (O $_{3}$ ) is a key oxidant and pollutant in the lower atmosphere. Significant increases in surface O $_{3}$ have been reported in many cities during the COVID-19 lockdown. Here we conduct comprehensive observation and modeling analyses of surface O $_{3}$ across China for periods before and during the lockdown. We find that daytime O $_{3}$ decreased in the subtropical south, in contrast to increases in most other regions. Meteorological changes and emission reductions both contributed to the O $_{3}$ changes, with a larger impact from the former especially in central China. The plunge in nitrogen oxide (NO $_{x}$ ) emission contributed to O $_{3}$ increases in populated regions, whereas the reduction in volatile organic compounds (VOC) contributed to O $_{3}$ decreases across the country. Due to a decreasing level of NO $_{x}$ saturation from north to south, the emission reduction in NO $_{x}$ (46%) and VOC (32%) contributed to net O $_{3}$ increases in north China; the opposite effects of NO $_{x}$ decrease (49%) and VOC decrease (24%) balanced out in central China, whereas the comparable decreases (45-55%) in these two precursors contributed to net O $_{3}$ declines in south China. Our study highlights the complex dependence of O $_{3}$ on its precursors and the importance of meteorology in the short-term O $_{3}$ variability.

36 pages, 16 figures. Published in Science of the Total Environment

References in corpus (1)

The seesaw impacts between reduced emissions and enhanced AOC on O $_{3}$ during the COVID-19