A Study on the Domestic and Transboundary Impacts of High-Concentration PM-2.5 Generated by Large-Scale Wildfire in South Korea

In March 2025, a series of large-scale wildfires that broke out across central and southeastern regions of South Korea rapidly burned vast areas of forest and released substantial amounts of combustion products and PM-2.5 into the atmosphere. This study comprehensively analyzed the spatiotemporal characteristics of PM-2.5 generated by the wildfires and assessed the domestic and transboundary impacts of wildfire smoke, utilizing satellite imagery, ground-based air quality monitoring networks, and atmospheric modeling.According to real-time PM-2.5 monitoring data from South Korea, extremely high concentrations exceeding 246 μg/m³ were observed in areas near the wildfire originating between March 25 and 26. Elevated PM-2.5 concentrations were also detected across western Japan. Analysis of VIIRS satellite-based active fire data and wind vector fields indicated that the wildfires spread rapidly over a wide area within a short time. Furthermore, AOD data from the GK-2B satellite and RGB/false-color imagery from Himawari-8 visually confirmed that wildfire smoke containing high aerosol concentrations had reached Japan. HYSPLIT backward trajectory analysis also suggested that the air masses arriving in western Japan likely originated from the wildfire-affected areas in southeastern Korea within 24 hours. This study demonstrates that large-scale wildfires can significantly deteriorate regional air quality across national borders in a short period. It highlights the urgent need for enhanced cooperation among East Asian countries and the development of an integrated satellite-ground-based monitoring system to effectively address transboundary air pollution caused by extreme wildfire events.