制造业集聚与企业减污:大气污染和水体污染的差异

Manufacturing Agglomeration and Enterprise Pollution Reduction:The Difference between Air Pollution and Water Pollution

推动制造业高质量发展,需要深化和创新制造业集聚,促进企业绿色低碳转型。本文基于1998-2014年中国工业企业数据库与中国工业企业污染排放数据库的合并数据,采用Bartik方法构建城市层面的外部需求作为工具变量,精细甄别了制造业集聚对企业水体污染和大气污染排放的差异化影响。基准回归结果表明,样本期制造业集聚加剧了企业工业化学需氧量排放、抑制了企业二氧化硫排放。机制分析表明,制造业集聚所带来的规模效应、技术效应大体相仿,结构效应却迥异,即制造业集聚显著降低了煤炭消费占比和能源强度,这是其抑制企业二氧化硫排放的重要原因,不过,制造业集聚降低了企业循环用水率,还提高了新鲜水资源消耗占比,这是其加剧企业工业化学需氧量排放的重要原因。异质性分析表明,制造业集聚对国有企业、非高技术行业和城市集聚水平较高地区企业工业化学需氧量排放的促进作用更大,对非国有企业、高技术行业和高集聚水平地区企业二氧化硫排放的抑制作用更强。本文研究为推进企业减污降碳协同增效提供了有益启示。

Since the introduction of the reform and opening up policy,the geographical agglomeration characterized by industrial parks and industrial clusters has increased the economic efficiency of enterprises in the agglomeration area,and is an important symbol of China's economic growth miracle.At the same time,the phenomenon of pollution spread highly overlaps with the economic agglomeration area,and many pollution phenomena such as heavy metals in rivers and haze weather have become common,which attracts considerable attention to the relationship between agglomeration and pollution.Based on the China's micro enterprise data from 1998 to 2014,this paper uses the Bartik method to construct the external demand at the urban level as a tool variable,and carefully screens the differential impact of manufacturing agglomeration on water pollution and air emissions of enterprises.The benchmark regression results show that during the sample period,manufacturing agglomeration has intensified the COD emissions of enterprises and restrained the SO,emissions.The mechanism analysis shows that the scale effect and technical effect brought by manufacturing agglomeration are generally similar,but the structural effect is quite different:the manufacturing agglomeration has significantly reduced the coal consumption and energy intensity,which is an important reason for the curbed SO,emissions among enterprises.However,the manufacturing agglomeration has reduced the rate of water recycling of enterprises,while increased the fresh water consumption,which is an important reason for the higher COD emissions among enterprises.Heterogeneity analysis shows that manufacturing agglomeration plays a greater role in increasing the COD emissions of state-owned enterprises,enterprises in non-high-tech industries and enterprises in areas with higher urban agglomeration level,and in inhibiting the SO,emissions in non-state-owned enterprises,high-tech industries and areas with high agglomeration level.This paper draws the following policy implications.First,it's important to pay attention to the pollution reduction mechanism of enterprises,and promote enterprise pollution reduction by category.This paper empirically finds that the impact of manufacturing agglomeration on water pollution and air pollution is very different.For air pollution,pollution reduction and carbon reduction can achieve synergy and increasing the use of clean energy is an effective means;for water pollution,it is necessary to step up efforts to fight pollution at the source,increase water recycling,and promote the conservation and efficient use of water resources.Second,to build a beautiful China,promote green development and effectively improve environmental quality,we need to tighten control over energy intensity and consumption.This paper empirically finds that manufacturing agglomeration can reduce the intensity of SO,and COD emissions,but aggravates COD emissions and increases the consumption of fresh water.Therefore,we should timely consider promoting the dual control of the intensity and consumption of water resources.Third,we should continue to pursue innovation-driven development.As we move to the stage of high-quality development,it is still necessary to maintain a relatively stable proportion of the manufacturing industry,and there is still a conflict between the expansion of the production capacity of the manufacturing industry and the pollution reduction of enterprises.Therefore,we should take the supply-side structural reform as the main line,adhere to the innovation-driven development policy,strengthen the supporting role of green scientific and technological innovation,and promote enterprises to go green and low-carbon.