The driving factors of air quality index in China

In recent years, serious air pollution episodes in China have received increasing academic attention due to their adverse impacts. Drawing on Air Quality Index data in 2015 across 338 Chinese cities, this study investigated the spatiotemporal patterns of the air pollution in China and identified the effect intensity and interaction among the driving factors using the geographical detector model. The results indicate that air pollution levels in 2015 in China are still high on the whole, with PM2.5, PM10, and O-3 as the major primary pollutants. Temporally, air pollution in China presents a U-shape pattern over the year, while the primary pollutants vary across seasons. Spatially, air pollution in China is characterized by spatial clustering and witnesses higher levels in Northern China and Xinjiang Province and lower levels in Southern China, but the location of some air pollution hot spots change by seasons. Spatial patterns of the primary pollutants are divided into five types of region according to their occurrence frequency. On average, natural factors are found to exert more effects on air pollution in China than socioeconomic factors. Additionally, interactions among the driving factors have either nonlinear-enhanced or bi-enhanced effects on air pollution. Findings from the study have several important policy implications for mitigating air pollution in China. (C) 2018 Published by Elsevier Ltd.