Observation of Aqueous Processing of Organic Aerosol Components in Fog Water at Baengnyeong Island, South Korea

Understanding atmospheric processes leading to the formation and chemical evolution of aerosol is essential in current climate and air quality research. Liquid water suspended in the atmosphere (i.e., fog and cloud droplets) is a medium in which organic oxidation reactions occur, allowing formation of aqueous secondary organic aerosol (aqSOA) material. However, research is needed to show the conditions under which these reactions occur and the chemical mechanisms by which additional organic aerosol mass is generated.

Dense fog events are frequently observed during late spring and mid-summer in the Yellow Sea in Southeast Asia, along with high concentrations of particulate and gaseous pollutants. Fog water samples were collected at Baengnyeong Island, South Korea in the summer of 2014 to look for chemical and physical signatures of aqueous oxidation reactions. Chemical concentrations were measured including total organic carbon, organic acids, anions, cations, reduced sulfur, peroxides, acidity and formaldehyde. Photo-oxidation reactions of a model aqSOA precursor were carried out within selected fog water samples. Results of these analyses may include evidence of oxidation reactions leading to the formation of aqSOA within the fog droplets intercepted at Baengyeong Island.