講演情報
[AAS08-P40]Seasonal Variation in Mass Absorption Efficiency of Black Carbon in Korea
*Sujung Lee1、Giyeol Lee1、Jungmin Park2、Kwangyul Lee2、Pilho Kim2、Yongjoo Choi1 (1.Department of Environmental Sciences, Hankuk University of Foreign Studies、2.Air Quality Environment Research Division, Climate and Air Quality Research Department, National Institute of Environmental Research, Incheon, Republic of Korea)
キーワード：
Black Carbon、Mass Absorption Efficiency、multiple-scattering correction factor
Elemental carbon (EC), which strongly absorbs visible light, is also referred to as black carbon (BC), and the linkage between EC and BC is quantified by Mass Absorption Efficiency (MAE). To reduce uncertainties in conversion from BC to EC, accurate MAE values that reflect seasonal, regional, and emission-specific variability are required. Therefore, we analyzed seasonal variations of MAE in Korea by collecting carbonaceous aerosols using a low-volume sampler (LAS-16) at Air Quality Research Centers (AQRC) in Gyeonggi (37.31°N, 126.80°E) and Chungcheong (36.78°N, 126.49°E), South Korea. EC was analyzed using a DRI Model 2015 (Magee Scientific) thermal-optical reflectance (TOR) analyzer following the IMPROVE-A protocol, and MAE was calculated by dividing the EC absorption coefficients at 808 nm by the corresponding mass concentrations with a multiple-scattering correction factor (C) of 2.14. The means of MAE808 nm during winter were 9.3 m2 g-1 in Gyeonggi and 7.4 m2 g-1 in Chungcheong, with the highest MAE observed in October (9.8 m2 g-1) and November (8.2 m2 g-1), respectively. To compare online-based MAE, we applied the same approach using an aethalometer (AE33; Magee Scientific) and a Semi-Continuous OC-EC Field analyzer (Sunset Laboratory Inc., USA) at seven AQRCs in Korea during 2022. Calculated MAE (18.2 m2 g-1) was highly overestimated compared to filter-based MAE because the embedded factor (C = 1.39), which depends on the filter tape and optical properties of the collected particles, may be inappropriate. When we applied empirical filter-based MAE (8.35 m2 g-1), appropriate C was identified as ~3.03, which is lower than the value reported by Yus-Diez et al. (2025) (C = 3.81). Due to differences in regional and emission-specific characteristics, it is necessary to use appropriate C factors and MAE values that represent the characteristics of the Korean environment.