Spillover Effects and Performance Optimization of Air Pollution Control Policies: Evidence from the Yangtze River Delta Region, China

Government policy is crucial to control air pollution, while industrial structure upgrading and green technology progress are needed to optimize air pollution control performance (APCP). Meanwhile, policy spillovers from one region to another affect the APCP. This study applied systems theory to explain the mechanisms that drive both environmental policy spillover and APCP. We evaluated the APCPs of 41 cities in the Yangtze River Delta region from 2006 to 2020 using a super-efficiency SBM-DEA model. We then analyzed the paths by which industry and technology drive APCP using a spatial Durbin model (SDM) and investigated heterogeneity across different regional governance groups. The effects generated by the regulatory spillover of air pollutants were decomposed into four subsystems: chain transmission effect, vibration effect, ripple effect, and halo effect. The results show the following: (1) Throughout the study period, the APCP of most of the regional governance groups in the Yangtze River Delta region showed a fluctuating trend with continuous improvement. The APCP was higher and more stable in the Zhejiang Province in the southeast, and lower and more drastic in the Jiangsu and Anhui Provinces in the north, and shows a significant positive spatial correlation. (2) Industrial structure upgrading and green technology progress had different impact paths on the APCP. Industrial structure upgrading had a significant indirect contribution to the APCP, but the direct effect was not significant. Green technology progress had a significant direct inhibitory effect and an indirect promoting effect on the APCP. (3) In the optimization path of the APCP, industrial structure upgrading played a more important role than green technology progress, but they did not reinforce each other's enhancement of the APCP. (4) There was regional heterogeneity in the impacts of industry and technology on the APCP. The paths and actual effects of industry and technology on the APCP varied greatly among different regional governance groups.