The central environmental protection inspection (CEPI) system is an innovative institutional arrangement in China's environmental supervision mechanism. It is of great practical significance to explore its air pollution control effect. Using the daily panel data of 337 cities in China from October 1, 2015 to December 31, 2019, this paper empirically tests the improvement of urban air quality by the first round of CEPI and the “look-back” policy using a two-way fixed effect model. The results show that both the first round of CEPI and the “look-back” policy can significantly improve the air quality in the supervised areas on the whole, but their improvement effects on different pollutants show heterogeneity. The first round of CEPI has strong sustainability and can improve air quality for a long time, but the “look-back” policy does not have the effect of long-term pollution control, and objectively there is a certain phenomenon of “retaliatory pollution”. These two policies have different treatment effects on different pollutants, and have significant regional heterogeneity. The control effect of CEPI on air pollution is regulated by human capital, technological innovation and industrial structure, showing strong heterogeneity. This study has certain theoretical value and guiding significance for further improving the system design of the CEPI and improving the effect of air pollution governance.

中央环保督察制度是中国环境监管机制中一项创新性制度安排,探究其空气污染治理效果具有重要的现实意义。本文利用中国337个城市2015年10月1日至2019年12月31日的日度面板数据,采用双向固定效应模型实证检验了首轮中央环保督察和 “回头看”政策对城市空气质量改善的治理效应。结果表明:无论是首轮中央环保督察还是 “回头看”政策,总体上都能够显著地改善被督察地区的空气质量,但其对不同污染物改善效果均呈现出异质性特征。首轮中央环保督察具有较强的可持续性,能够长期改善空气质量,但 “回头看”政策却不具备长期治污功效,并且客观上存在一定的 “报复式污染”现象。首轮中央环保督察和 “回头看”两种政策针对不同污染物的治理效果表现不同,并具有显著的区域异质性。中央环保督察对空气污染的治理效果受到人力资本、技术创新和产业结构的调节作用而呈现出较强的异质性特征。本研究对于进一步完善中央环保督察的制度设计,改善空气污染治理效果具有一定的理论价值和指导意义。