对外开放、城市蔓延与大气污染

Opening up,Urban Sprawl,and Air Pollution

文章基于开放经济与城市视角,利用中国270个地级及以上城市2006—2018年数据,构建动态面板两步SYS-GMM与DIF-GMM模型,实证分析对外开放、城市蔓延及两者交互项对大气污染的影响。并进一步以对外开放为门槛,搭建面板门槛模型探讨城市蔓延的环境效应。结果显示:现阶段贸易开放、投资开放均加剧了大气污染,城市蔓延对大气污染影响为正,但未通过检验,对空气污染影响具有不确定性;贸易开放与城市蔓延的关联效应则缓解了污染程度,投资开放与城市蔓延的关联效应加剧了污染排放;城市蔓延对空气污染的贸易开放门槛效应显示,在未达到门槛之前,城市蔓延的环境效应是不确定的,跨过门槛值之后,城市蔓延则产生了负的环境外部性;城市蔓延的投资开放门槛效应显示,未达到门槛时,城市蔓延抑制了空气污染,但未形成显著性效应,跨过门槛后,城市蔓延则加剧了大气污染;以城市规模进行异质性分析发现,大中小城市之间存在显著差异性。

Based on the perspective of open economy and cities,this paper uses the data of 270 cities in China from 2006 to2018 to build dynamic panel two-step SYS-GMM and DIF-GMM models,empirically analyzes the impact of opening up,urban sprawl,and their interaction on air pollution,and further builds a panel threshold model to explore the environmental effects of urban sprawl.The results show that both trade opening and investment opening aggravate air pollution at present.Urban sprawl has a positive impact on air pollution,but it does not pass the test,and its impact on air pollution is uncertain;the correlation effect between trade openness and urban sprawl alleviates the pollution level,while the correlation effect between investment openness and urban sprawl intensifies the pollution emission;the trade opening threshold effect of urban sprawl on air pollution shows that the environmental effect of urban sprawl is uncertain before the threshold is reached,and after the threshold is crossed,urban sprawl produces negative environmental externalities;the threshold effect of investment openness of urban sprawl shows that when the threshold is not reached,urban sprawl suppresses air pollution,but does not form a significant effect.After crossing the threshold,urban sprawl aggravates air pollution;by analyzing the heterogeneity of city size,it is found that there are significant differences between large,medium and small cities.