The heterogeneous air pollution response to shrunk socio-economic activities in 28 major northern cities of China

Abstract

Heterogeneity in air quality response to implemented measures is apparent in many studies, yet the role of regional socio-economic features in the response mechanism remains unclear. This study uses empirical method to identify the direct impact of socio-economic factors on the response to interventions of economy. We constructed a counterfactual model using machine learning methods to quantitatively assess dynamic changes in air pollution based on multiple socio-economic drivers. We find that economy interventions have indeed had an apparent but temporary impact on air quality in northern China. NO2 concentrations decreased by 45.98%, 22.81%, and 0.2%, respectively, at different policy stages, while PM2.5 decreased by 38.66%, 21.63%, and 3.62%, respectively, on average. In contrast, O3 increased by 18.62% and then returned to normal levels. We also find the heterogeneous effect of air pollutants on human activity restrictions in cities with hierarchical socio-economic backgrounds. Highly industrialized cities face greater difficulties in reducing emissions, and cities with a higher urbanization rate may have a more urgent need to take action on O3 governance. Factors such as regional economic development level, industrial structure and urbanization should be considered as important indicators in the development of hierarchical environmental control policies. Our results shed light on the dynamic changes in air pollution due to reduced socio-economic activities, and the heterogeneity between cities should be taken into account when formulating future policies in response to major events and climate change.