长江经济带制造业集聚对环境污染的门槛效应研究

Threshold Effect of Manufacturing Agglomeration on Environmental Pollution in Yangtze River Economic Belt

基于2009~2018年长江经济带108个地级及以上城市面板数据,采用区位商指数测度制造业集聚水平,从大气环境、水环境、能源消耗3个维度选取指标构建环境污染指数;在厘清制造业集聚的环境效应形成机理的基础上,构建基准回归模型、门槛回归模型实证检验长江经济带制造业集聚对环境污染的影响。研究结果显示:(1)2009~2018年长江经济带下游地区制造业集聚水平最高,中游地区次之,上游地区最低。(2)长江经济带环境污染水平整体呈下降趋势,且下游地区城市环境污染改善速度高于中上游地区。(3)长江经济带整体及中下游地区制造业集聚与环境污染表现出先促增、后抑制、再加剧的“N”型曲线关系,而上游地区制造业集聚仍处于加剧污染的阶段。为促进长江经济带制造业绿色发展,应统筹兼顾长江经济带制造业集聚与生态环境的良性互动关系,因地制宜推动制造业差异化发展,实施更严格的环境规制标准,提升制造业绿色技术创新水平,加强绿色制造体系建设。

Based on the panel data of 108 cities in the Yangtze River Economic Belt from 2009-2018, this paper selects indicators from atmospheric environment, water environment and energy consumption to construct an environmental pollution index, and uses the location quotient index to measure the level of manufacturing agglomeration. On the basis of clarifying the mechanism of the environmental effect of manufacturing agglomeration, this paper uses benchmark regression model and threshold regression model to empirically test the impact of manufacturing agglomeration on environmental pollution in the Yangtze River Economic Belt. The results show that:(1) From 2009 to 2018, the manufacturing agglomeration level in the lower reaches of the Yangtze River Economic Belt was the highest, followed by the middle reaches, and the upper reaches was the lowest.(2) The overall environmental pollution level of the Yangtze River Economic Belt shows a downward trend, and the improvement of urban environmental pollution in the lower reaches is higher than that in the middle and upper reaches.(3) The whole Yangtze River Economic Belt and the middle and lower reaches of the Yangtze River show an “N” curve relationship between manufacturing agglomeration and environmental pollution, which first promotes, then inhibits and then intensifies. However, the manufacturing agglomeration in the upper reaches is still in the stage of aggravating pollution. We should balance the benign relationship between manufacturing agglomeration and environmental pollution, continuously increase the investment in environmental protection science and technology, strictly enforce environmental regulations, and formulate the differentiation policy of manufacturing industry agglomeration in the Yangtze River Economic Belt.