Assessing the co-benefits of CO_2 mitigation on air pollutants emissions from road vehicles

摘要

This paper quantitatively assesses the co-benefits of atmospheric CO_2 stabilization at 400 ppmv by 2100 on air pollutants emissions from road vehicles using a global energy system model treating the road transport sector in detail. It is estimated that the reduction rate of global cumulative emissions of SO_2, NO_χ and PM from road vehicles during the period 2020-2100 in the 400 ppmv CO_2 stabilization scenario compared to the no CO_2 constraint scenario is 22.1%, 10.8%, and 14.4%, respectively. Such co-benefits are the largest for SO_2 because biomass-derived Fischer-Tropsch products are chosen as a major alternative fuel for road transport in the former scenario and because their SO_2 emission factor is zero, whereas their NO_χ and PM emission factors are lower than those for petroleum products only by 27% and 21%, respectively. This implies that introducing liquid biofuels would not lead to a noticeable reduction in NO-χ and PM emissions. Such co-benefits are the smallest for NO-χ. The first reason is that, except for 2100 in the no CO_2 constraint scenario, heavy-duty trucks account for the largest share of global road vehicles' NO_χ emissions in the two scenarios throughout the time horizon. The second reason is that in each time period, heavy-duty trucks emit almost the same amount of SO_2, NO_χ and PM between the scenarios because of almost the same technology and fuel choices in this sector. This implies the necessity of promoting R&D for developing cost-effective low-carbon alternatives to diesel heavy-duty trucks to achieve a further reduction in global air pollutants emissions from road vehicles.