Vehicle Emission Pathway Analysis by Fuel Type in Korea Using Emission Inventory

ABSTRACT Road transport is a major source of urban air pollution, and various policies have been introduced to control vehicle emissions to improve urban air quality. This study analyzes emission trends and fuel‐specific emission pathways of NO x and PM 2.5 from road transport using an inventory‐based framework. It also proposes this framework as a practical proxy indicator for interpreting whether policy implementation in road transport is reflected in national emission inventories. The emission pathways, representing relative changes in vehicle registrations and emission intensity, were derived from the national emission inventory for 2016–2022. Using 2016 as the baseline, this study compared the emission pathways of diesel and all fuel types to examine whether fuel‐specific changes associated with policy implementation were observed. During the study period, vehicle air pollutant emissions steadily decreased, and the registration share of diesel vehicles, the largest contributor to emissions, declined from 43% to 39%. In contrast, the share of eco‐friendly vehicles, including hybrids, among newly registered vehicles increased from 4% to 25%. The fuel‐based analysis showed that vehicle registration activity for diesel vehicles decreased more markedly than that of other fuel types. These findings suggest that dynamic changes in emission inventories can serve as a reference for interpreting policy implementation and supporting future policy evaluation, providing a practical tool for strategy development based on current emission changes.