[A-AS11] 大気化学

[AAS11-P09] Quantitative assessment of the light absorption properties of water-soluble organic carbon at industrial/urban site in Korea

*minseo lee¹、Chisung Yoon¹、Kwangyul Lee²、Pilho Kim²、Yongjoo Choi¹ (1.Department of Environmental Sciences, Hankuk University of Foreign Studies, Yongin, South Korea、2.Air Quality Environment Research Division, National Institute of Environmental Research, Incheon, Republic of Korea)

キーワード：water insoluble organic carbon, Absorption angstrom exponent, Mass Absorption Efficiency

Brown Carbon (BrC) accounts for 19–40% of the total light absorption by strong absorption properties in ultraviolet and short visible wavelengths. Among BrC, water-soluble organic carbon (WSOC) is characterized by its ability to dissolve in water, so its behavior in the atmosphere and its climate impact differs from those of insoluble BrC. The key parameters for evaluating light absorption properties of WSOC were the absorption Ångström exponent (AAE) and mass absorption efficiency (MAE), but there are insufficient information about its absorption properties in Korea. In this study, the light absorption properties of WSOC were analyzed using quartz filter collected in Ansan, Korea, where is the industrial and urban complex city. To investigate the its seasonal variation, the samples were collected during 12 h on a preheated quartz filter (550℃, 5 hours) using a low-volume sampler (LAS-16, EMA ENG) in February, May, August, and November 2024. An ultrapure water extraction technique was applied to minimize optical interference from insoluble components such as black carbon (BC) and mineral dust. The AAE values were derived by converting absorbance values into absorption coefficients using an UV-Vis spectrometer (UV-1280, Shimadzu) which can measure the absorption spectrum at a resolution of 1 nm in the 200–900 nm wavelength range. This study will allow us to identify factors affecting BrC absorption and to quantitatively assess the contribution of emission sources by region.