The Impact of Smart City Construction on PM2.5 Concentrations: Empirical Analysis from Chinese Counties

Fine particulate matter (PM2.5) pollution poses a major threat to human physical and mental health. Smart cities (SCs) provide innovative paths for PM2.5 pollution prevention and control through Internet of Things (IoT) monitoring, intelligent transportation optimization, and other technological means. Based on the panel data of 2,141 counties in China between 2006 and 2021, this paper constructs a difference-in-differences with multiple time periods (MDID) to systematically assess the impact of SC on PM2.5 concentration and analyze its mechanism of action by combining the satellite remote sensing PM2.5 concentration (PM2.5C) and the list of smart city pilots. This study finds the following: (1) SC significantly reduced the PM2.5 concentration in the test area by about 3.58%. This conclusion was verified through rigorous robustness testing; (2) SC can effectively reduce PM2.5C through the innovation effect; (3) High-quality economic development can strengthen the emission reduction effect of SC on PM2.5C; (4) The environmental benefits of SC show significant spatial heterogeneity, with the largest PM2.5 reductions occurring in the western regions (4.3% reduction), followed by regions with mature digital infrastructure and cities in high administrative level cities. The results of this study provide a reference for the regional differentiated implementation of the “14th Five-Year Plan for the Development of Innovative Smarter Cities”, and make targeted recommendations for the synergistic management of air quality under the “dual-carbon” goal.