Assessing climate/air quality synergies and cost-effectiveness for Beijing transportation: Insights into sustainable development

CO₂ emission reduction policies can simultaneously reduce air pollutant emissions in the transport sector, but the extent of their cost-effective is under-evaluated. To explore sustainable transportation in a mega-city, the potential synergies and cost-effectiveness of CO₂ and air pollutant emission reductions in Beijing transportation are quantitatively evaluated by radar chart analysis, total cost of ownership (TCO) and marginal abatement cost curves (MACC) under various mitigation measures. The findings show that the adoption of electric light-duty vehicles can achieve a significant synergistic effect and cost-effectiveness of emission reductions, and would be implemented as a high priority. Moreover, improving emission standards and fuel economy have an obvious cost-effectiveness and effective mitigation for air pollutants, but with poor synergies due to low CO₂ mitigation. In contrast, the clean energy for large and heavy vehicles, and bio-fuel for aviation are essential measures for achieving carbon neutrality, but with high costs. Furthermore, changes of transport modes have good cost-effectiveness, but there are no synergies due to the emission increments of PM_2.5 and NO_x. Given that transportation plays a crucial role in achieving carbon neutrality and enhancing air quality, more stringent and effective environmental policies targeting emission reduction can expedite the sustainable transition in Beijing transportation.