This paper examines the effects of imports and exports on China's PM2.5 pollution using data from 31 provinces during the period 2001-2016.At the aggregate level,our analysis shows that exports have a pollution-generating effect while imports have a pollution-shifting effect on provincial PM2.5 pollution.Cross-sectional analysis reveals that imports and exports exhibit opposite effects on manufacturing and high-tech industries,but demonstrate the same pollution-generating effect for the heavy industry sector.At the regional level,the effects are similar to those at the aggregate level.We also examine the impacts of other factors on PM2.5 pollution.Our empirical evidence shows that PM2.5 pollution is positively correlated with domestic sales,population density,economic growth,urbanization rate,and transportation,but negatively correlated with energy efficiency and industry structure.This paper suggests that reducing exports and increasing imports will help to reduce PM2.5 pollution.