Effects of Industrial Structure and Industrial Scale on SO2 Emission Intensity: Evidence from the Yangtze River Economic Belt

Industrial transformation and regional economic integration have reshaped the spatial distribution and cross-regional spillover patterns of industrial air pollution. Using a spatial panel model and data from 118 prefecture-level units in the Yangtze River Economic Belt (YEB) during 2011–2020, this study examines the direct and spatial spillover effects of industrial structure adjustment and industrial scale expansion on industrial SO2 emission intensity. The results reveal significant spatial dependence in industrial SO2 emission intensity, with high-intensity areas concentrated mainly in the upstream YEB and low-intensity areas distributed primarily in the midstream and downstream regions. Industrial structure adjustment is significantly associated with lower local industrial SO2 emission intensity but it generates emission reduction spillovers in neighboring prefecture-level units. In contrast, industrial scale has no significant direct local effect, whereas industrial scale expansion in neighboring units produces significant emission reduction spillovers, highlighting the roles of interregional collaboration and technology diffusion. These findings demonstrate the potential contributions of industrial structure adjustment and industrial scale expansion to cross-regional pollution reduction and indicate that ignoring spatial dependence may lead to biased estimates and policy assessments. This study provides empirical evidence for coordinated pollution control and sustainable regional development in the YEB and other rapidly industrializing regions.