Multi-Aspect Analysis of Wildfire Aerosols from the 2023 Hongseong Case: Physical, Optical, Chemical, and Source Characteristics

This study characterized the aerosol changes during the April 2023 Hongseong wildfire in Chungcheongnam-do, Korea, using physical, optical, and chemical data from the Anmyeon-do Global Atmosphere Watch station. The observation period was divided into three distinct phases: immediately after the wildfire (Period I), during precipitation (Period II), and the re-entry of wildfire smoke after precipitation (Period III). During Periods I and III, the PM10 mass concentrations were 75.7 ± 31.2 and 98.2 ± 55.6 µg/m3, respectively, which were approximately 2.4 and 3.1 times higher than the 2023 annual average (31.8 µg/m3) at the Anmyeon-do site. Aerosol scattering coefficients increased by factors of 4.0 and 6.9, and absorption coefficients by 5.5 and 4.2, respectively. Source apportionment using real-time data from a Monitor for Aerosols and Gases in ambient Air (MARGA) instrument combined with PCA demonstrated that aerosol emissions during Periods I and III were predominantly influenced by biomass burning sources. Analysis of PM10 and PM2.5 filter samples showed biomass burning markers, such as K+ and C2O42−, increased by 5.5–31.4 times compared with those in Period II. Elevated levels of combustion-related elements, including S, K, V, and Pb, further confirmed the influence of wildfire smoke on air quality during the affected periods.