Kim, Hwajin Collier, Sonya Ge, Xinlei Xu, Jianzhong Sun, Yele Jiang, Wenqing Wang, Youliang Herckes, Pierre Zhang, Qi 2024-01-19T20:32:32Z 2024-01-19T20:32:32Z 2021-09-02 2019-03-01 1352-2310 https://pubs.kist.re.kr/handle/201004/120243 A field study on fog chemistry and aqueous-phase processing of aerosol particles was conducted in Fresno, California's San Joaquin Valley (SJV) during wintertime. Fog droplets were collected while interstitial submicron aerosol was characterized in real time using a High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-AMS). The fog samples were later analyzed using HR-AMS, ion chromatography (IC), and total organic carbon analyzer (TOC). Compared to interstitial aerosol, dissolved solutes in fog waters were composed of higher fractions of ammonium, nitrate, sulfate, methanesulfonic acid, and oxygenated organic compounds, likely due to aqueous formation of secondary species as well as enhanced gas-to-particle partitioning of water-soluble gases under humid conditions. The low-volatility dissolved organic matter in fog water (F-OA) was moderately oxidized with an average oxygen-to-carbon (o/C) ratio of 0.42. The chemical composition of F-OA appeared to be overall similar to that of oxygenated organic component in interstitial aerosol (OOA) and the HR-AMS mass spectra of F-OA and OOA are highly similar (r(2) > 0.95). However, there are also significant chemical differences as F-OA appeared to contain a larger fraction of carboxylic functional groups than OOA, indicating enhanced organic acid formation through aqueous-phase reactions. In addition, F-OA was composed of substantially more nitrogen-containing compounds, with an average N/C ratio 4 times that of OOA. Most strikingly was that the F-OA spectra showed substantial enhancements of the CxHyN2+ (x >= 0; y >= 0) ions, which were likely contributed by imidazole- and/or pyrazine-based compounds formed from the aqueous reactions of aldehydes with amino compounds. The results of this study demonstrated that aqueous reactions in atmospheric droplets can significantly modify aerosol composition and contribute to the formation of oxygenated and nitrogen-containing organic compounds in atmospheric aerosol particles. This finding is important for understanding aerosol's effects on human health, air quality, and climate. English PERGAMON-ELSEVIER SCIENCE LTD AQUEOUS-PHASE REACTIONS CALIFORNIA CENTRAL VALLEY GLYOXAL UPTAKE MOUNTAIN SITE CLOUD-WATER CHEMISTRY MATTER SOA METHYLGLYOXAL CARBONYL Chemical processing of water-soluble species and formation of secondary organic aerosol in fogs Article 10.1016/j.atmosenv.2018.11.062 1 ATMOSPHERIC ENVIRONMENT, v.200, pp.158 - 166 ATMOSPHERIC ENVIRONMENT 200 158 166 scie scopus 000458225500015 2-s2.0-85058820045 Environmental Sciences Meteorology & Atmospheric Sciences Environmental Sciences & Ecology Meteorology & Atmospheric Sciences Article AQUEOUS-PHASE REACTIONS CALIFORNIA CENTRAL VALLEY GLYOXAL UPTAKE MOUNTAIN SITE CLOUD-WATER CHEMISTRY MATTER SOA METHYLGLYOXAL CARBONYL Fog chemistry Aqueous phase reactions Secondary aerosol formation