Elucidating contributions of meteorology and emissions to O3 variations in coastal city of China during 2019–2022: Insights from VOCs sources

Elucidating the meteorology and emissions contribution of O3 variation is a crucial issue for implementing effective measures for O3 pollution control. We quantified the impacts of meteorology and emissions on O3 variability during spring and autumn from 2019 to 2022, using multi-year continuous observations. A machine learning (ML)-based de-weathering model revealed that meteorology accounted for a greater proportion of O3 variability (71.9% in spring and 57.4% in autumn) compared to emissions (28.1% and 42.6%, respectively). In spring, relative humidity (RH, 22.8%) and wind speed (WS, 13.7%) were key drivers, contributing to O3 decreases and increases, respectively. During autumn, temperature (T, 10.8%) and surface solar radiation (SSR, 9.45%) were the dominant factors, both contributing to O3 production. We assessed the O3 formation sensitivity based on VOCs emissions sources and evaluated the importance of emission by O3 production rate (P(O3)) calculated from box model and the positive matrix factorization (PMF) model. Vehicle emissions and solvent use were identified as the major contributors to O3 formation from 2019 to 2022 and reducing them would be beneficial for O3 pollution control. This study elucidates the relative roles of meteorological conditions and anthropogenic emissions in O3 variability and key insights for formulating future O3 control policies. [Display omitted] •Meteorology contributed 57–69% of multi-year O3 variability in a coastal city.•The key meteorological factors were RH and WS in spring, and T and SSR in autumn.•O3 production was dominated by HO2 + NO (averaged 64%), followed by RO2 + NO.•Vehicle emissions and solvent use were significant contributors to O3 production.