Evaluating the effect of low-carbon city pilot policy on urban PM2.5: evidence from a quasi-natural experiment in China

Evaluating the effect of low-carbon city pilot (LCCP) policy is of vital importance for urban ecological construction. This study aims to deeply explore the effect of LCCP policy on urban air pollutant PM2.5. Using China's prefecture-level panel data during 2004-2020, this research adopts the difference-in-difference model to evaluate the effect of LCCP policy on urban PM2.5 and considers the heterogeneity of policy effect from the perspective of urban resource endowment and industrial characteristics. Also, this study analyzes mechanism affecting urban PM2.5 by mediation effect model. In addition, this paper explores the spatial spillover effect of the LCCP policy. The results indicate that the LCCP policy has significantly reduced urban PM2.5. The heterogeneity analysis shows that the effect of LCCP policy in declining resource-based cities is the largest, followed by regenerated resource-based cities and non-resource-based cities. The effect of LCCP policy on PM2.5 in non-old industrial-based cities is greater than that in old industrial-based cities. The impact mechanism analysis indicates that the effect of LCCP policy could be achieved through promoting technological innovation, public transportation, and industrial agglomeration. The LCCP policy has reduced the PM2.5 of neighboring pilot cities, but it has insignificant effect on neighboring non-pilot cities.