Abstract Using the synthetic difference-in-differences method, this study evaluates the comprehensive effects of the ‘coal-to-gas’ policy in China following its complete implementation in 2017. We propose four channels through which the policy could affect the air quality in untreated cities. The findings reveal a significant decrease in air pollution levels, as measured by PM10, in both the treated and untreated areas. However, the net spillover effect in the treated and untreated areas exhibits heterogeneous spatial distribution patterns due to different mechanisms. These differences could be related to the political economy and natural geography of China.
Yixuan Wang (Tue,) studied this question.