Characterization of ambient volatile organic compounds, source apportionment, and the ozone–NO<sub>x</sub>–VOC sensitivities in a heavily polluted megacity of central China: effect of sporting events and emission reductions

Abstract. The implementation of strict emission control during the 11th National Minority Games (NMG) in September 2019 provided a valuable opportunity to assess impact such controls on characteristics VOCs and other air pollutants. Here, we investigated O3–NOx–VOC sensitivity comprehensively Zhengzhou before, during, after NMG by delivering field measurements combined with WRF-CMAQ (Weather Research Forecasting Community Multiscale Air Quality) model simulations. average mixing ratios periods were 121 ± 55 µg m?3 decreased about 19 % 11 before reduction. ozone precursors (NOx) also significantly period; however, pollution was severe entire observation period. Positive matrix factorization analysis indicated seven major sources ambient VOCs, including coal combustion, biomass burning, vehicle exhausts, industrial processes, biogenic emissions, solvent utilization, liquefied petroleum gas (LPG). results show that source as combustion reduced As for formation potential (OFP), value period 183 115 m?3, which 0.23 0.17 times lower than period, respectively. Solvent utilization most important measures taken reduce OFP Control policies can effectively carcinogenic risk. However, non-cancer risks VOC exposures all exceeding safe level (hazard quotient = 1) sampling periods, emphasis reduction acrolein emissions needed. In addition, simulation O3 controlled Zhengzhou. Empirical Kinetic Modeling Approach showed NOx might lead higher pollution. It is suggested (VOCs : NOx) should be more 2, alleviate