Effect of Synergistic Emission Reduction in Air Pollutants and Greenhouse Gases and the Associated Health Benefits

The transport sector contributes significantly to greenhouse gases and airborne pollutants. This study focuses on the co-benefits related to decreases in air pollutants and CO2 emissions under various mitigation scenarios. The associated mitigations in PM2.5 concentrations are predicted by establishing a random forest (RF) model and the health benefits are evaluated with the global exposure mortality model (GEMM). Environmental tax values and carbon trading prices are integrated alongside traditional elasticity coefficients and coordinate-based approaches to transform reductions into economic advantages. The results indicate that in the most favorable scenario (ELC), CO2 emissions are expected to peak in 2032 with a reduction of 51.71%; this is supported by the marginal CO2 emission curve, which intersects the zero axis around that same year, while the air pollution equivalents (APeq) are projected to decline by 25.65% in 2050. The efficiency of synergistic reductions between air pollutants and CO2 ranks as SO2 > NOX > CO > HC > PM2.5 > PM10, and the elasticity coefficients for all pollutants are gradually aligning toward 1, suggesting that stricter mitigation efforts will enhance co-benefits. Furthermore, the economic benefits attributable to CO2 reduction are anticipated to be 10.81 billion CNY by 2050, and 17,297 premature deaths associated with PM2.5 exposure could be prevented. The findings in this study could provide essential insights for the co-management of CO2 and air pollutants from road mobile sources.