Coordinated reduction of pollutant and carbon emissions through smart city construction: TOE-based mechanisms and spatial spillovers in China

Abstract

The coordinated reduction of pollutant and carbon emissions (CRPC) has become a central objective of urban environmental governance. Although smart city construction is primarily intended to advance digital urban transformation, its role in CRPC remains insufficiently understood. Using panel data for 259 prefecture-level cities in China from 2006 to 2022, this study examines whether smart city construction promotes CRPC. Exploiting the staggered rollout of the national smart city pilot policy, we estimate a multi-period difference-in-differences (DID) model to identify the policy effect. The results show that smart city construction significantly reduces both sulfur dioxide emission intensity and carbon emission intensity, indicating a clear CRPC effect. The findings remain robust to parallel-trend tests, placebo tests, propensity score matching, alternative variable specifications, and the inclusion of additional policy controls. Mechanism analyses based on the technology-organization-environment (TOE) framework show that smart city construction promotes CRPC by stimulating green innovation and digital infrastructure development, advancing industrial upgrading and human capital accumulation, and strengthening ecological investment and pollution control capacity. Further analyses indicate that the effect is stronger in cities with more stringent environmental regulation, in growing cities, and in non-resource-based cities. Smart city construction also generates positive spillover effects across geographically proximate and economically connected cities. Overall, the findings show that smart city construction can serve as an important pathway toward integrated pollution and carbon governance.