Does industrial symbiotic agglomeration reduce pollution emissions: evidence from eco-industrial demonstration parks in China

Industrial symbiotic agglomeration is important for promoting the circular economy and reducing pollution emissions. This paper examines the effects of industrial symbiotic agglomeration on pollution emissions using the staggered difference-in-difference model. The findings suggest the following: (1) industrial symbiotic agglomeration reduces total urban pollution emissions, with significant reductions in SO2 and wastewater, although not in solid waste and PM2.5 emissions. (2) The emission reduction effect is achieved mainly through green innovation, the recycling effect, and structural optimization, whereas the cost reduction effect of symbiotic agglomeration is not obvious. (3) Industrial symbiotic agglomeration promotes emission reduction in neighboring cities within a 300-km range, and this reduction decays with geographical distance. In addition, the pollution emission reduction effect of industrial symbiotic agglomeration is only realized when its size reaches 187.17 km2, with the effect becoming stronger as the size increases. At present, industrial symbiotic agglomeration mainly plays an emission reduction effect in non-resource cities. This paper provides a new way to promote the green development of industry and region.