Spatial Variation of the Effect of Multidimensional Urbanization on PM_2.5 Concentration in the Beijing-Tianjin-Hebei...

Atmospheric PM_2.5 pollution has become a prominent environmental problem in China, posing considerable threat to sustainable development. The primary driver of PM_2.5 pollution in China is urbanization, and its relationship with PM_2.5 concentration has attracted considerable recent academic interest. However, the spatial heterogeneity of the effect of urbanization on PM_2.5 concentration has not been fully explored. This study sought to fill this knowledge gap by focusing on the Beijing-Tianjin-Hebei (BTH) urban agglomeration. Urbanization was decomposed into economic urbanization, population urbanization, and land urbanization, and four corresponding indicators were selected. A geographically weighted regression model revealed that the impact of multidimensional urbanization on PM_2.5 concentration varies significantly. Economically, urbanization is correlated positively and negatively with PM_2.5 concentration in northern and southern areas, respectively. Population size showed a positive correlation with PM_2.5 concentration in northwestern and northeastern areas. A negative correlation was found between urban land size and PM_2.5 concentration from central to southern regions. Urban compactness is the dominant influencing factor that is correlated positively with PM_2.5 concentration in a major part of the BTH urban agglomeration. On the basis of these findings, BTH counties were categorized with regard to local policy recommendations intended to reduce PM_2.5 concentrations.