The effect of anthropogenic emission, meteorological factors, and carbon dioxide on the surface ozone increase in China from 2008 to 2018 during the East Asia summer monsoon season.

Despite the implementation of the Clean Air Action Plan by the Chinese government in 2013, the issue of increasing surface ozone (O 3) concentrations remains a significant environmental concern in China. In this study, we used an improved regional climate–chemistry–ecology model (RegCM-Chem-YIBs) to investigate the impact of anthropogenic emissions, meteorological factors, and CO 2 changes on summer surface O 3 levels in China from 2008 to 2018. Compared to its predecessor, the model has been enhanced concerning the photolysis of O 3 and the radiative impacts of CO 2 and O 3. The investigations showed anthropogenic emissions were the primary contributor to the O 3 increase in China, responsible for 4.08–18.51 ppb in the North China Plain. However, changed meteorological conditions played a crucial role in decreasing O 3 in China and may have a more significant impact than anthropogenic emissions in some regions. Changed CO 2 played a critical role in the variability of O 3 through radiative forcing and isoprene emissions, particularly in southern China, inducing an increase in O 3 on the southeast coast of China (0.28–0.46 ppb) and a decrease in southwest and central China (- 0.51 to - 0.11 ppb). Our study comprehensively analyzed O 3 variation across China from various perspectives and highlighted the importance of considering CO 2 variations when designing long-term O 3 control policies, especially in high-vegetation-coverage areas. [ABSTRACT FROM AUTHOR]