Marginal Abatement Costs and Pollution–Carbon Co-Governance in Sustainable Urban Transitions: Evidence from the Yangtze River Delta
Abstract
Urban agglomerations concentrate activities that generate both PM2.5 pollution and carbon emissions, but the economic basis for governing them jointly remains unclear. Taking the Yangtze River Delta as a case, this study evaluates pollution–carbon co-governance from a marginal abatement cost (MAC) perspective. Using panel data for 41 cities from 2011 to 2023, we estimate shadow prices and MACs under joint and single-objective abatement scenarios with a non-radial directional distance function dual model. We then construct carbon-reduction and pollution-reduction cost-saving effects, classify synergy types, and examine their temporal, spatial, and nonlinear transition patterns. The results show that joint abatement generally lowers the MACs of both carbon mitigation and PM2.5 reduction, with stronger cost-saving on the pollution side. Under the baseline classification, the share of balanced synergy increases over time, and the balanced state shows high persistence in Markov transitions. Core cities show weaker measured cost-saving effects, which may reflect limited remaining low-cost co-abatement potential rather than weak governance. Semiparametric evidence further indicates that industrial upgrading, openness, and urbanization are nonlinearly associated with MACs and synergy balance. These findings suggest that urban pollution–carbon coordination should be guided by local cost structures and development stages.