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Title: Biogenic, urban, and wildfire influences on the molecular composition of dissolved organic compounds in cloud water

Organic aerosol formation and transformation occurs within aqueous aerosol and cloud droplets, yet little is known about the composition of high molecular weight organic compounds in cloud water. Cloud water samples collected at Whiteface Mountain, New York, during August-September 2014 were analyzed by ultra-high-resolution mass spectrometry to investigate the molecular composition of dissolved organic carbon, with a focus on sulfur- and nitrogen-containing compounds. Organic molecular composition was evaluated in the context of cloud water inorganic ion concentrations, pH, and total organic carbon concentrations to gain insights into the sources and aqueous-phase processes of the observed high molecular weight organic compounds. Cloud water acidity was positively correlated with the average oxygen : carbon ratio of the organic constituents, suggesting the possibility for aqueous acid-catalyzed (prior to cloud droplet activation or during/after cloud droplet evaporation) and/or radical (within cloud droplets) oxidation processes. Many tracer compounds recently identified in laboratory studies of bulk aqueous-phase reactions were identified in the cloud water. Organosulfate compounds, with both biogenic and anthropogenic volatile organic compound precursors, were detected for cloud water samples influenced by air masses that had traveled over forested and populated areas. Oxidation products of long-chain (C 10-12) alkane precursors were detected during urban influence. Influencemore » of Canadian wildfires resulted in increased numbers of identified sulfur-containing compounds and oligomeric species, including those formed through aqueous-phase reactions involving methylglyoxal. Light-absorbing aqueous-phase products of syringol and guaiacol oxidation were observed in the wildfire-influenced samples, and dinitroaromatic compounds were observed in all cloud water samples (wildfire, biogenic, and urban-influenced). Overall, the cloud water molecular composition depended on air mass source influence and reflected aqueous-phase reactions involving biogenic, urban, and biomass burning precursors.« less
Authors:
 [1] ; ORCiD logo [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [1] ;  [7] ;  [5] ; ORCiD logo [8] ; ORCiD logo [9]
  1. Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Chemistry
  2. Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Chemistry and Michigan Society of Fellows; Univ. of California, Riverside, CA (United States). Dept. of Environmental Sciences
  3. Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Chemistry; Univ. of Washington, Seattle, WA (United States). Dept. of Chemistry
  4. Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Chemistry; Purdue Univ., West Lafayette, IN (United States). College of Veterinary Medicine
  5. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
  6. Adirondack Lake Survey Corp. (ALSC), Ray Brook, NY (United States)
  7. Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Chemistry; Northwestern Univ., Evanston, IL (United States). Dept.of Chemistry
  8. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL); Purdue Univ., West Lafayette, IN (United States). Dept. of Chemistry
  9. Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Chemistry and Dept. of Earth and Environmental Sciences
Publication Date:
Report Number(s):
PNNL-SA-130575
Journal ID: ISSN 1680-7324
Grant/Contract Number:
53968; AC05-76RL01830
Type:
Accepted Manuscript
Journal Name:
Atmospheric Chemistry and Physics (Online)
Additional Journal Information:
Journal Name: Atmospheric Chemistry and Physics (Online); Journal Volume: 17; Journal Issue: 24; Journal ID: ISSN 1680-7324
Publisher:
European Geosciences Union
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23); New York State Energy Research and Development Authority (NYSERDA); New York State Department of Environmental Conservation (NYSDEC); Univ. of Michigan, Ann Arbor, MI (United States); National Oceanic and Atmospheric Administration (NOAA), Boulder, CO (United States)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; Environmental Molecular Sciences Laboratory
OSTI Identifier:
1434664