Response of PM2.5 variations to changing urbanization process in different climatic backgrounds of China

Understanding how urban air pollution responds to urbanization is significant to formulating PM2.5 mitigation strategies. However, the dynamic response of PM2.5 to the process of urbanization has not been well discussed. This study attempted to attribute the variation characteristics of PM2.5 in 264 cities of China to some representative socioeconomic indicators in 3 different Köppen-Geiger climate zones. The main findings can be generated as followed: (1) Remarkable improvement in air quality was found in most case cities (∼95%) across different climate zones from 2015 to 2019, with average concentration declining from 51.10 (2015) to 38.13 μg/m3 (2019). (2) Urban development posed significant contribution to the changes in PM2.5 pollution, but the major responsible urbanization indicators varied in different climate zones. (3) There was potential interaction of different climatic indicators on the environmental effect of the urbanization process in different climate zones. The significance of this study is the preliminary evidence placed on the dynamic response of PM2.5 to urbanization process. In the future, more comprehensive studies on the driving difference of PM2.5 from an imbalanced urbanization process will contribute to better understanding the coupling relationship between urban development and environmental risks.