Heterogeneity and the determinants of PM_2.5 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_2.5. This paper investigates the spatiotemporal characteristics of PM_2.5 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_2.5. The results indicate that the annual concentrations of PM_2.5 in the YREB were 23.49-37.37 μg/m³, with an initial increase and a later decrease. PM_2.5 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_2.5 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_2.5. Our findings contribute to a better understanding of the impact mechanisms of PM_2.5 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.