Wildfires are a significant source of atmospheric aerosols and can strongly affect regional air quality. In April 2023, a large wildfire occurred in Hongseong, western Korea. This study investigates the impact of the Hongseong wildfire on the chemical, physical, and optical properties of atmospheric aerosols observed at the Anmyeondo site. Quasi-real-time aerosol measurements were analyzed to examine variations in aerosol mass concentration, size-related characteristics, and optical parameters, as well as chemical composition, before, during, and after the wildfire event. Source apportionment analysis was applied to identify contributions from biomass burning relative to other emission sources. During the wildfire period, enhanced aerosol loading and biomass-burning-related components were observed, accompanied by changes in aerosol optical behavior. These results indicate that the Hongseong wildfire had a notable influence on aerosol properties at Anmyeondo, including both chemical composition and optical characteristics, despite the site being located downwind of the fire region. This study highlights the role of regional wildfire events in modifying aerosol physical and radiative properties at coastal background sites and emphasizes the importance of integrated observations for understanding wildfire impacts.

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 PM_2.5 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.