The effects and mechanisms of low-carbon transition promoting air quality improvement: based on empirical evidence of low-carbon city pilot policy

In the context of the "Dual Carbon" strategic goals, promoting a comprehensive green transition of the economy and society has become a national strategic priority. Using the low-carbon city pilot policy as a quasi-natural experiment, this study empirically analyzes its impact on urban air quality and the underlying mechanisms. Based on panel data from 282 prefecture-level cities in China from 2008 to 2022, a multi-period difference-in-differences (DID) model is constructed. The results indicate that the low-carbon city pilot policy significantly improves urban air quality, a finding that remains robust after a series of rigorous tests. The policy primarily achieves this improvement by enhancing green economic efficiency and promoting industrial structure upgrading. Furthermore, the positive effects are more pronounced in non-provincial capital cities, larger cities, cities with greater local government fiscal investment and cities in high-energy-consumption regions. Interestingly, the level of urban infrastructure plays a negative moderating role; the more developed the infrastructure, the weaker the marginal improvement effect of the policy. Based on these findings, this study proposes policy recommendations, including implementing differentiated strategies and encouraging enterprises to actively pursue green transformation to achieve sustained air quality improvement.