环境执法监督与空气质量—来自中央环保督察的准自然实验证据

2016年确定的中央环保督察旨在对环境执法监督形式进行创新性改革,是中国推进生态文明建设的重大制度安排,空气质量被生态环境部纳入督察工作的重点内容.采集全国256个地级及以上城市的面板数据,利用中央环保督察这一准自然实验,使用多期双重差分法评估其对空气质量的改善效果.结果表明:中央环保督察对空气质量指数的降低发挥了显著作用,被督察省份的空气质量指数(AQI)平均下降3.184个单位;单项污染物治理效果表明,中央环保督察对PM10、SO2、O3浓度的降低有显著贡献,但对PM2.5、NO2和CO浓度的影响不显著;进一步地,运用平行趋势检验、反事实检验与倾向得分匹配检验证明回归结果的可靠性;动态效应分析发现,中央环保督察的政策效果具有滞后性,并且随着反馈意见的颁布减弱;机制检验与异质性分析结果表明,中央环保督察政策效果呈现东部、西部、中部地区逐渐减弱的现象,且中央环保督察对空气质量的影响机制中存在技术创新效应.

Environmental Law Enforcement Supervision and Air Quality:Quasi-natural Experimental Evidence from Central Environmental Protection Inspectorate

The central environmental protection inspection determined in 2016 aims to carry out innovative reforms in the form of environmental law enforcement and supervision. It is a major institutional arrangement for China to promote the construction of ecological civilization. Air quality is included in the inspection work by the Ministry of Ecology and Environment.Panel data from 256 prefecture-level and above cities across the country were used,and the quasi-natural experiment of the Central Environmental Protection Inspectorate were used, and the multi-period double difference method to evaluate the effect of improving air quality wre utilized. The results show that the central environmental protection inspector plays a significant role in reducing the air quality index, and the AQI of the inspected provinces has dropped by about 3.184 units on average; heterogeneity analysis shows that the central environmental inspector makes a significant contribution to the reduction of PM10, SO2, and O3 concentrations. But the improvement effect on PM2.5, NO2 and CO concentration is not obvious; further, parallel trend test, counterfactual test and propensity score matching test are used to prove the reliability of regression results. The dynamic effect analysis show that the policy effect of the central environmental protection inspector is lagging and weakened with the issuance of feedback.