A comprehensive investigation of surface ozone pollution in China, 2015–2019: Separating the contributions from meteorology and precursor emissions

Despite the considerable reductions in primary and secondary air pollutants China, surface ozone levels have increased recent years. We report a trend of 3.3 ± 4.7 ?g.m ?3 year ?1 annual mean maximum daily average over an 8-h period (MDA8 ozone) across China between 2015 2019. Leveraging Kolmogorov–Zurbenko filter method, we find that meteorology enhanced Beijing–Tianjin–Hebei (BTH), Yangtze River Delta (YRD), Pearl (PRD) while reduction solar radiation planetary boundary layer height accelerated decreases Sichuan Basin (SCB) after 2017. Solar temperature increases, together with sea level pressure, were main contributors to enhance YRD. They also contributed 32% increases BTH. Weaker meridional wind, lower relative humidity, higher escalated enhancement PRD 2016 2018. Regarding precursor emissions, NO 2 long-term components showed noticeable decline all regions 2017, partially due introduction most current action plan reduce In contrast, satellite-retrieved data suggest VOC concentrations did not change substantially target during study period. After however, VOCs slightly BTH, YRD, PRD, which might be driven by enhancements. Overall, impact on variations was dominant SCB from Precursor played leading role found BTH YRD transitional formation regime tended more x -sensitive. • Variations polluted investigated. Meteorology exacerbated pollution PRD. emissions changed, decreased 2017 regions. mixed regime, experienced -limited ones.