Can transportation infrastructure reduce haze pollution in China?

Traffic emission is one of the main sources of haze pollution, but few studies have evaluated the dynamic impact and mechanism of transportation infrastructure on haze pollution based on a spatial perspective. This study selects the annual data of 30 provinces in China from 2000 to 2017 and uses a dynamic spatial Durbin model to study the dynamic impact of transportation infrastructure on haze pollution. The results show that transportation infrastructure has a significant spatial spillover effect on haze pollution, and the spatial spillover effect has regional heterogeneity. Specifically, whether long term or short term, highway traffic has a boosting effect on haze pollution, while railway traffic has an inhibitory effect on haze pollution. In addition, transportation infrastructure can affect haze pollution through three paths: expanding economic scale, promoting transformation of industrial structure, and promoting technological progress. At the regional level, the improvement of highway traffic density in eastern, central, and western regions will significantly increase haze pollution. The enhancement of railway traffic density has a significant inhibitory and boosting effect on haze pollution in central and western regions, respectively. For the eastern region, railway traffic construction can only restrain local haze pollution, but cannot exert the spatial spillover effect of railway traffic to reduce haze. The conclusions of this paper provide policy inspirations for giving full play to the haze reduction effect of transportation infrastructure and the development of green transportation.