国家自主创新示范区建设对城市空气污染的影响研究——基于准自然实验的证据

Impacts of National Independent Innovation Demonstration Zone Construction on Urban Air Pollution:Evidence from a Quasi-Natural Experiment

在中国经济增长放缓和空气污染加剧的双重压力下,依靠创新驱动实现降污减排是改善空气质量的关键。使用2003—2019年中国285个城市的面板数据,基于国家自主创新示范区建设试点构建一个准自然实验,通过渐进双重差分法探索创新驱动发展对城市空气污染的影响与机制。结果表明:(1)相比于非试点城市,试点城市工业二氧化硫排放水平显著降低,国家自主创新示范区建设可以有效降低城市空气污染;(2)机制分析发现,国家自主创新示范区建设试点可以促进技术创新、优化产业结构,进而实现降污减排;(3)异质性分析表明,国家自主创新示范区建设的减排效应在大中城市、高人力资本城市、第二产业占比较低的城市中更强。据此建议推广国家自主创新示范区建设,发挥其溢出效应和带动作用,重视人力资本效能,促进城市节能减排和绿色发展。

Under the dual pressure of slowing economic growth and increasing air pollution in China,innovation-driven strategies and technologies become the key to achieving pollution reduction and low carbon development.Using panel data from 285 cities in China from 2003 to 2019,a quasi-natural experiment is constructed.Based on the pilot National Independent Innovation Demonstration Zone(NIIDZ)construction,we explore the impact and mechanism of innovation-driven development on urban air pollution through the time-varying difference-in-differences(DID)method.The results show that:(1)the creation of NIIDZ can effectively reduce urban air pollution;(2)mechanism analysis finds that this pilot policy can promote technological innovation and optimize industrial structure,thus achieving pollution reduction;(3)heterogeneity analysis suggests that the emission reduction effect is stronger in cites which are in large and medium-sized,with high quality human capital,and with a lower share of secondary industries.Therefore,the construction of NIIDZ could be adopted to give full play to its spillover effect and driving effect,attach importance to human capital effectiveness,promote energy saving,emission reduction and urban green development.