Heterogeneous Environmental Regulation on the Impact Mechanism and Spatial Spillover Effects of the Synergistic Effect of Pollution Reduction and Carbon Emission Reduction

In light of China's "Double Carbon" ambitions and the urgent need to promote ecological civilization construction, this study empirically examines the influence of varied environmental regulations on the synergistic effect of pollution reduction and carbon emission reduction. The two-way fixed-effects model and the Spatial Durbin Model (SDM) are used to analyze panel data from 30 provinces (2011–2022).The results show that command-and-control and public-participation regulation have significant negative impacts on synergy, whereas market-incentive regulation has a positive one; the effects vary across East/Central/West China (e.g., market-incentive regulation performs best in Central China); and market-incentive regulation has positive spatial spillover.Suggestions: Prioritize market instruments, put in place region-specific regulation schemes, and improve cross-regional collaboration to increase synergy and sustainably advance ecological civilization.