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Abstract

Tropospheric ozone (O-3) concentration is increasing in China along with dramatic changes in precursor emissions and meteorological conditions, adversely affecting human health and ecosystems. O-3 is formed from the complex nonlinear photochemical reactions from nitrogen oxides (NOx = NO + NO2) and volatile organic compounds (VOCs). Although the mechanism of O-3 formation is rather clear, describing and analyzing its changes and formation potential at fine spatial and temporal resolution is still a challenge today. In this study, we briefly summarized and evaluated different approaches that indicate O-3 formation regimes. We identify that atmospheric oxidation capacity (AOC) is a better indicator of photochemical reactions leading to the formation of O-3 and other secondary pollutants. Results show that AOC has a prominent positive relationship to O-3 in the major city clusters in China, with a goodness of fit (R-2) up to 0.6. This outcome provides a novel perspective in characterizing O-3 formation and has significant implications for formulating control strategies of secondary pollutants. (C) Higher Education Press 2022