A series of emission reduction measures were conducted in Wuhan, Central China, to ensure good air quality during the 7th Military World Games (MWG) in October 2019. To better understand the implications for ozone (O3) pollution control strategies, we applied integrated analysis approaches based on the de-weathered statistical model, parameterization methods, chemical box model, and positive matrix factorization model. During the MWG, concentrations of O3, NOx, and volatile organic compound (VOCs), OFP (O3 formation potential), LOH (OH radical loss rate) were 83 µg/m3, 43 µg/m3, 26 ppbv, 188 µg/m3, and 3.9 s-1, respectively, which were 26%, 18%, 3%, 15%, and 13% lower than pre-MWG values and 6%, 39%, 30%, 33%, and 50% lower than post-MWG values, respectively. After removing meteorological influence, O3 and its precursors during the MWG decreased largely compared with post-MWG values, and only O3, NO2, and oxygenated VOCs (OVOCs) declined compared with pre-MWG values, which revealed the emission reduction measures during the MWG played an important role for O3 decline. For six VOCs sources, the mass contributions of biomass burning and solvents usage during the MWG decreased largely compared with pre-MWG values. O3 production was sensitive to VOCs and the key species were aromatics, OVOCs, and alkenes, which originated mainly from solvents usage, biomass burning, industrial-related combustion, and vehicle exhaust. Decreasing O3 concentration during the strict control was mainly caused by OVOCs reduction due to biomass burning control. Generally, the O3 abatement strategies of Wuhan should be focused on the mitigation of high-reactivity VOCs.
Keywords: Ozone; Random forest; Relative incremental reactivity; Source apportionment; VOCs; Wuhan Military World Games.
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