Can the opening of high-speed rail boost the reduction of air pollution and carbon emissions? Quasi-experimental evidence from China

This study utilizes panel data from 282 cities in China and employs the difference-in-differences method, mediating effect model, social network analysis method, and spatial econometric model to thoroughly investigate the impact of high-speed rail development on urban air pollution and carbon emissions reduction. The results of the study revealed that the introduction of high-speed railways correlated negatively with metropolitan PM2.5 and carbon emissions, suggesting a reduction in urban air pollutants and carbon emissions. The impact of high-speed rail installation on urban air pollution and carbon emissions reduction depends on various factors, such as the metropolitan area's location, size, and access to resources. Moreover, by optimizing the industrial structure and promoting technological innovation within the metropolitan region, high-speed rail installation can contribute to efforts to reduce air pollutants and carbon emissions. Over time, the influence of high-speed rail on industrial structure and technological development becomes increasingly significant. In urban centers connected to high-speed rail networks, the introduction of high-speed rail plays a significant role in fostering the reduction of urban air pollution and carbon emissions. Given the spatial correlation, the advent of high-speed rail will impact not only local air pollution and carbon reduction processes but also those of neighboring cities.