Local and Regional Contributions to Primary and Secondary PM2.5 in Korea
MINSU CHOI, Qi Ying,
Texas A&M University Abstract Number: 370
Working Group: Source Apportionment
AbstractAir pollution is a major public health concern in South Korea, primarily caused by PM
2.5. Previous studies have suggested that PM2.5 from China accounted for a significant fraction of the total PM
2.5 in Korea. However, due to recent emission reductions in China, it is necessary to re-evaluate the contributions of local and regional sources of PM
2.5 in Korea. This study employed the Community Multiscale Air Quality (CMAQ) model with a source and age tracking framework to quantitatively analyze the contribution of domestic and international sources to PM
2.5 in Korea in 2020. The study used the Regional Emission Inventory in Asia v3.2.1 (REAS3.2.1) for anthropogenic emissions. Anthropogenic emissions from Korea were adjusted based on reported 2020 provincial emissions. To more accurately resolve the meteorological fields under complex terrain conditions and improve the prediction of PM
2.5 in Korea, nested domains with spatial resolutions down to 4 km were used. The low-spatial resolution REAS emissions were upscaled using high-resolution spatial allocation surrogates and an extensive database of the location of fossil fuel-fired power plants. The study found that while uncertainties in the heterogenous uptake of N
2O
5 and NO
2 affected nitrate concentrations near the source regions, the amount of long-range transported nitrate from China was less affected. While China still significantly influenced PM
2.5 concentrations in Korea, especially during spring, domestic sources also had a comparable contribution to the regionally transported PM
2.5 during the summer months. The study concluded that while reducing emissions in China would lead to an improvement in PM
2.5 air quality in downwind regions compared to the levels seen in the 2010s, high pollution episodes will still have a large impact on regional transport. Both domestic and international efforts are necessary to efficiently mitigate air pollution in Korea and protect public health in the future.