Characteristics of Aerosol Mass Concentration and Chemical Composition of the Yellow and South Sea around the Korean Peninsula Using a Gisang 1 Research Vessel

Abstract

Northeast Asian regions have recently become the main source of anthropogenic and natural aerosols. Measurement of aerosols on the sea in these regions have been rarely conducted since the experimental campaigns such as ACE-ASIA (Asian Pacific Regional Aerosol Characterization Experiment) in 2001. Research vessel observations of aerosol mass and chemical composition were performed on the Yellow and south sea around the Korean peninsula. The ship measurements showed six representative cases such as aerosol event and non-event cases during the study periods. On non-event cases, the anthropogenic chemical and natural soil composition on the Yellow sea were greater than those on the south sea. On aerosol event cases such as haze, haze with dust, and dust, the measured mass concentrations of anthropogenic chemical and element compositions were clearly changed by the events. In particular, methanesulfonate (MSA⁻, CH₃SO₃⁻), a main component of natural oceanic aerosol important for sulfur circulation on Earth, was first observed by the vessel in Korea, and its concentration on the Yellow sea was three times that on the south sea during the study period. Sea salt concentration important to chemical composition on the sea is related to wind speed. Coefficients of determination (R²) between wind speed and sea salt concentration were 0.68 in PM 10 and 0.82 in PM 2.5. Maximum wave height was not found to be correlated to the sea salt concentration. When sea-salt comes into contact with pollutants, the total sea-salt mass is reduced, i.e., a loss of Cl⁻ concentration from NaCl, the main chemical composing sea salt, is estimated by reaction with HNO₃(gas) and H₂SO₄(gas). The Cl⁻ concentration loss by SO₄ 2− and NO₃⁻ more easily increased for PM 10 compared to PM 2.5. The results of this study will be applied to verifying a dust-haze forecasting model. In addition, continued vessel measurements of aerosol data will become important to research for climate change studies in the future.