To achieve air quality levels comparable to those in major cities in developed countries, it is essential to strengthen environmental policies related to automobiles.
Compared to cities such as Los Angeles in the United States and London in the United Kingdom, automobile-related air pollutant emissions per 100,000 population and per urban area in Seoul are not significantly lower. This is noteworthy because Seoul has one of the highest population densities in the world, making it challenging to maintain air quality levels similar to those of advanced countries, even if per capita air pollutant emissions are similar.
Additionally, Seoul’s air quality is impacted by long-range transport from surrounding countries, including China, particularly during winter. As a result, to achieve global city-level air quality under these conditions, Seoul must implement stricter environmental policies related to vehicle traffic than other advanced cities.
In 2019, vehicles of Korean Emission Standards (KES) 4 to 5 that traveled through Seoul were found to have emitted a significant amount of nitrogen oxides, accounting for 34% of total vehicle emissions, and PM2.5, accounting for 58% of total vehicle emissions.
Traffic data was analyzed by grouping it according to KES in order to estimate automobile air pollutant emissions in Seoul. The analysis revealed that light-duty diesel trucks and small and medium-sized RV diesel vehicles were the largest contributors to nitrogen oxide and PM2.5 emissions among KES 4 to 5 vehicles.
Strengthening support for the conversion of light-duty diesel trucks and RV vehicles to eco-friendly vehicles, as well as early scrapping, is necessary.
Based on the traffic volume-based air pollutant emissions estimated in this study, it would be effective to prioritize the conversion of light-duty trucks and small and medium-sized RV diesel vehicles in Seoul. Therefore, it is necessary to plan for incentives and allocate a budget for early scrapping of these vehicles. Further research is needed to evaluate automobile policies that consider both PM2.5 concentration and number concentration, as well as non-exhaust emissions.