Author(s)

MD. SANIUL ALAM, BERNARD HYDE, PAUL DUFFY, AONGHUS MCNABOLA

Abstract

This paper addresses the co-benefits of climate change mitigation policies to reduce PM_2.5 pollution for passenger cars (PCs) using a scenario-based approach in Ireland. To analyse future scenarios (2015–2035), estimation was initially conducted in COPERT software. Emissions estimation was improved using an add-on module to the COPERT model that was capable of considering a range of future vehicle technologies and the contribution of additional non-exhaust PM_2.5 emissions from road abrasion. A fleet, disaggregated at major fuel type, and at the level of newly registered and survived PCs, was required for this add-on module. The module was developed based on the concept, emission factors and fuel efficiency improvement factors from a number of previous research papers, and COPERT output, to estimate fuel-based emissions e.g. exhaust and non-exhaust PM_2.5 and CO₂ emissions. Three additional estimations were conducted in the add-on module: a baseline scenario that was similar to COPERT but accounted for a different disaggregation of the PC fleet, and two alternative scenarios. The two alternative scenarios were developed using an approach previously developed by the authors that addressed the existing Electric Vehicle (EV) policy in Ireland, and a possible ban on the sale of conventional vehicles powered by gasoline and diesel fuel in the future (in line with the planned actions of a number of EU cities). The results revealed that CO₂ emissions continuously decreased in the projection period, however, reductions of PM_2.5 reversed from the year 2028 due to increases in the non-exhaust component of PM_2.5 emissions. Under alternative scenarios, a 57–69% reduction of CO₂ could be possible whereas a 9-15% reduction for PM_2.5 could be achieved in 2035. Non-exhaust PM_2.5 was found to have a larger share (as much as 35 times that of exhaust emissions) in 2035 where alternative PCs such as EV represented a major share in the fleet. The research also provided a methodology capable of detailing the CO₂ and PM_2.5 emissions in future scenarios for a range of PC technologies.

Keywords

passenger car, policy analysis, CO₂, PM_2.5, co-benefit