Does county urban shrinkage in China affect the concentration of lung-accessible particulate matter? An analysis from...

The environmental effects of urban shrinkage have gradually attracted academic attention. Based on spatial effects and EKC perspectives, this study constructs an environmental impact assessment framework and examines the impact of urban shrinkage on the concentration of lung-accessible particulate matter at the county level in China from 2013 to 2020. The results show that, from a two-dimensional perspective in space and time, lung-accessible particulate matter concentrations show a decreasing trend in the time series and an obvious autocorrelation feature in space. Urban shrinkage can affect lung-accessible particulate matter concentrations through spatial effects. Through direct effects, urban shrinkage promotes the increase of lung-accessible particulate matter concentrations. Through spillover effects, urban shrinkage suppresses the growth of lung-accessible particulate matter concentrations. The effect of urban shrinkage on lung-accessible particulate matter concentration is nonlinear (EKC). This may be the result of the "siphon effect." Furthermore, in the extended STIRPAT model, it was found that population and economic and technological factors differentially affect lung-accessible particulate matter concentrations in shrinking cities. This study gives a new idea and insight into the changes in environmental pollution in shrinking cities.