The synergistic control effect of energy transition on carbon and hazardous air pollutant emissions embodied in provincial trade from the national value chain perspective.

Energy transition is the key to achieving synergistic pollution and carbon reduction, permeating all segments of the national value chain (NVC). However, the synergistic control effects of energy transition from NVC perspective had not been sufficiently researched. By integrating multi-regional input-output model, LMDI model and the Dagum Gini coefficient, a unified analytical framework was developed that included emission tracking, factor attribution, and disparity diagnosis. It revealed the synergistic control effects of the energy transition on CO2 and five air pollutants along NVC, alongside their regional differences. The results revealed that provincial energy transition was characterized by significant stages. CO2 emissions in NVC mainly embodied in the import, export intermediate products and final products. Air pollutant emissions primarily embodied in inter-provincial trade and export final products. Energy transition demonstrated significant co-benefits in controlling air pollutants and CO2 within NVC. This role rose steadily with variations in categories and regions. The overall disparity in synergistic control effects tended to decline. Intra-regional contribution was stable, while inter-regional and hyperbolic density fluctuated greatly. The research could provide empirical evidences for establishing a cross-regional dynamic compensation mechanism and differentiated governance approaches oriented toward the value chain.