Spatial effects of air pollutants reduction on CO₂ emissions

The sources of air pollutants and CO₂ are basically the same, hence the reduction of air pollutants will affect CO₂ emissions. Considering the regional integration of economic development as well as air pollution control, it is necessary to analyze the impact of air pollutants reduction in a region on CO₂ emissions in its surrounding regions. Furthermore, as different stages of air pollutants reduction have different effects on CO₂ emissions, it is also important to study the heterogeneity of this impact. In this article, we took China as the research case and built a spatial panel model based on the data of 240 cities above the prefecture level from 2005 to 2016 to study the impact of two different stages of air pollutants reduction-front reduction of air pollutants (FRAP) and end-of-pipe treatment of air pollutants (EPAP) on CO₂ emissions-and their spatial spillover effects. On this basis, we further modified traditional spatial weight matrix and constructed the matrices of cities in the same and different provinces to discuss the influence of provincial administrative boundaries on the spillover effect between cities. The results show that FRAP affects CO₂ emissions mainly through the local synergistic effect, and its spatial spillover effect is not significant. The local effect of EPAP on CO₂ emissions is antergic, and the spatial spillover effect is significant. The increase of a city's EPAP will increase the CO₂ emissions in surrounding regions. Besides, provincial boundaries weaken the spatial spillover effects of FRAP and EPAP on CO₂ emissions in prefecture-level cities. There is a significant spatial spillover effect between cities in the same province, but the spillover effect does not exist for cities in different provinces nearby.