South Korea, especially metropolitan area, has been suffering from high PM2.5 pollution. Comprehensive Plan on Fine Dust Management (CPFDM) was established to mitigate PM2.5 emissions. It indicates that transportation sector would reduce 8,600 tonnes of PM2.5 which is the most strict reduction target among major sectors. In 2018, 56% of budget for local PM2.5 mitigation measurement was spent for transportation sector, and notably, 71% of the budget for its sector was spent for subsidization of zero-emission vehicles (ZEVs) promotion. Previous studies have contributed to establishing PM2.5 mitigation policy but have not considered provincial features and sector-interaction. In that sense, integrated assessment model (IAM) could complement the shortcomings of previous studies. IAM capable of analyzing PM2.5 at Korean provincial level, however, has not been developed yet. This study aims i) to develop IAM that can represent Korean provincial-level spatial resolution of energy system and socioeconomics, ii) to model air pollutant emissions on GCAM-Korea focusing on road transportation sectors as a first step, and finally, iii) to examine zero-emission vehicles (ZEVs) subsidy policy effects on PM2.5 mitigation using the model.
GCAM-Korea is developed with a variety of provincial data collected, which represents 16 provinces’ socioeconomics and energy systems, keeping consistency with those of national level. Projected emissions compared to the national emissions inventory using GCAM-Korea works fairly well with empirical data across sectors and provinces except for VOC from light-duty vehicle 2-wheels (LDV2W) in which reported emissions in emissions inventory contradict energy use. ZEVs subsidy simulation shows that PM2.5 emissions decrease by 0.6-4.1% compared to baseline, and Seoul metropolitan area contributes 38-44% of overall PM2.5 emissions reduction. As ZEVs subsidies are weighted towards light-duty vehicle 4-wheels (LDV4W) sector, various spillover effects are found: ZEVs' share rises intensively in LDV4W sector, and this leads to an increase in its service cost, and at the same time, driving bus service cost relatively cheaper. This, in turn, drives an increase in bus service demand and emissions discharge. Furthermore, this type of impact from ZEVs subsidy could not reduce internal combustion engine vehicles (ICEVs) in freight truck, although diesel freight truck is a major contributor to PM2.5 emissions as well as NOx.
In future, ZEVs subsidy effect on air quality mitigation in truck and bus sectors should be further investigated through different scenario analyses. In addition, emissions modeling for other sectors such as power generation and industry sectors will be conducted to consider emissions caused by increasing electricity and hydrogen consumptions for ZEVs from the perspective of the whole energy system. It is expected to provide meaningful implications from cross-sector and cross-province aspects.
