Heterogeneity and the determinants of PM in the Yangtze River Economic Belt.

Haze has reached epidemic levels in many Chinese cities in recent years. Few studies have explored the determinants and heterogeneity of PM. This paper investigates the spatiotemporal characteristics of PM through spatial analytical methods based on aerosol optical depth data from the Yangtze River Economic Belt (YREB) between 2000 and 2017. Geographically weighted regression and geodetector models were applied to assess the heterogeneity of key factors influencing PM. The results indicate that the annual concentrations of PM in the YREB were 23.49-37.37 μg/m, with an initial increase and a later decrease. PM pollution showed a diagonal high spatial distribution pattern in the northeast and a low spatial distribution in the southwest, as well as a noticeable spatial convergence. The spatial variability of PM was enlarged, and its main fractal dimension was in the northeast-southwest direction. There were clear spatiotemporal variations in the impacts of natural and anthropogenic factors on PM. Our findings contribute to a better understanding of the impact mechanisms of PM and the geographic factors that form persistent and highly polluted areas and imply that more specific coping strategies need to be implemented in various areas toward successful particulate pollution prevention and control.