| Title: | Brown Carbon Production by Aqueous-Phase Interactions of Glyoxal and SO(2) |
| Author(s): | De Haan DO; Jansen K; Rynaski AD; Sueme WRP; Torkelson AK; Czer ET; Kim AK; Rafla MA; De Haan AC; Tolbert MA; |
| Address: | "Department of Chemistry and Biochemistry, University of San Diego, 5998 Alcala Park, San Diego, California 92110, United States. Cooperative Institute for Research in Environmental Sciences and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, United States" |
| ISSN/ISBN: | 1520-5851 (Electronic) 0013-936X (Linking) |
| Abstract: | "Oxalic acid and sulfate salts are major components of aerosol particles. Here, we explore the potential for their respective precursor species, glyoxal and SO(2), to form atmospheric brown carbon via aqueous-phase reactions in a series of bulk aqueous and flow chamber aerosol experiments. In bulk aqueous solutions, UV- and visible-light-absorbing products are observed at pH 3-4 and 5-6, respectively, with small but detectable yields of hydroxyquinone and polyketone products formed, especially at pH 6. Hydroxymethanesulfonate (HMS), C(2), and C(3) sulfonates are major products detected by electrospray ionization mass spectrometry (ESI-MS) at pH 5. Past studies have assumed that the reaction of formaldehyde and sulfite was the only atmospheric source of HMS. In flow chamber experiments involving sulfite aerosol and gas-phase glyoxal with only 1 min residence times, significant aerosol growth is observed. Rapid brown carbon formation is seen with aqueous aerosol particles at >80% relative humidity (RH). Brown carbon formation slows at 50-60% RH and when the aerosol particles are acidified with sulfuric acid but stops entirely only under dry conditions. This chemistry may therefore contribute to brown carbon production in cloud-processed pollution plumes as oxidizing volatile organic compounds (VOCs) interact with SO(2) and water" |
| Keywords: | "Aerosols *Carbon *Glyoxal Spectrometry, Mass, Electrospray Ionization Water;" |
| Notes: | "MedlineDe Haan, David O Jansen, Kevin Rynaski, Alec D Sueme, W Ryan P Torkelson, Ashley K Czer, Eric T Kim, Alexander K Rafla, Michael A De Haan, Audrey C Tolbert, Margaret A eng Research Support, U.S. Gov't, Non-P.H.S. 2020/04/02 Environ Sci Technol. 2020 Apr 21; 54(8):4781-4789. doi: 10.1021/acs.est.9b07852. Epub 2020 Apr 9" |
