The Interannual Variation of Transboundary Contributions from Chinese Emissions of PM2.5 to South Korea

In recent years, several studies pointed out that anthropogenic emission sources in China which significantly contribute to the PM2.5 mass burden was an important cause of particulate pollution in South Korea. However, most studies generally focused upon a single pollution event. It is rare to see comprehensive research that captures those features prone to interannual variations concerning the transboundary pollutant contribution in South Korea using a unified method. In this paper, we establish the emission inventories covering East Asia in 2010, 2015, and 2017, and then conduct the source apportionment by applying a coupled regional air quality model called the Integrated Source Apportionment Module (ISAM). Comparison of simulated and observed PM2.5 mass concentration at 165 CNEMC (China National Environmental Monitoring Center) sites suggests that the PM2.5 concentrations are well represented by the modeling system. The model is used to quantitatively investigate the contribution from emission sources in China to PM2.5 concentrations over South Korea and those features found to be prone to interannual variations are then discussed. The results show that the average annual contribution of PM2.5 has dropped significantly from 28.0% in 2010 to 15.7% in 2017, which strongly suggests that China has achieved remarkable results in the treatment of atmospheric particulates.