Comprehensive Insights Into O Changes During the COVID-19 From O Formation Regime and Atmospheric Oxidation Capacity.

Economic activities and the associated emissions have significantly declined during the 2019 novel coronavirus (COVID-19) pandemic, which has created a natural experiment to assess the impact of the emitted precursor control policy on ozone (O) pollution. In this study, we utilized comprehensive satellite, ground-level observations, and source-oriented chemical transport modeling to investigate the O variations during the COVID-19 pandemic in China. Here, we found that the significant elevated O in the North China Plain (40%) and Yangtze River Delta (35%) were mainly attributed to the enhanced atmospheric oxidation capacity (AOC) in these regions, associated with the meteorology and emission reduction during lockdown. Besides, O formation regimes shifted from VOC-limited regimes to NO-limited and transition regimes with the decline of NO during lockdown. We suggest that future O control policies should comprehensively consider the effects of AOC on the O elevation and coordinated regulations of the O precursor emissions.