Chemical characterization of SOA formed from aqueous-phase reactions of phenols with the triplet excited state of carbonyl and hydroxyl radical
Phenolic compounds, which are emitted in significant amounts from biomass burning, can undergo fast reactions in atmospheric aqueous phases to form secondary organic aerosol (aqSOA). In this study, we investigate the reactions of phenol (compound with formula C<sub>6</sub>H<sub>5&l...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2014-12-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/14/13801/2014/acp-14-13801-2014.pdf |
| _version_ | 1818020745906749440 |
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| author | L. Yu J. Smith A. Laskin C. Anastasio J. Laskin Q. Zhang |
| author_facet | L. Yu J. Smith A. Laskin C. Anastasio J. Laskin Q. Zhang |
| author_sort | L. Yu |
| collection | DOAJ |
| description | Phenolic compounds, which are emitted in significant amounts from biomass
burning, can undergo fast reactions in atmospheric aqueous phases to form
secondary organic aerosol (aqSOA). In this study, we investigate the
reactions of phenol (compound with formula C<sub>6</sub>H<sub>5</sub>OH)), guaiacol
(2-methoxyphenol), and syringol (2,6-dimethoxyphenol) with two major
aqueous-phase oxidants – the triplet excited states of an aromatic carbonyl
(<sup>3</sup>C<sup>*</sup>) and hydroxyl radical (· OH). We thoroughly
characterize the low-volatility species produced from these reactions and
interpret their formation mechanisms using aerosol mass spectrometry (AMS),
nanospray desorption electrospray ionization mass spectrometry (nano-DESI
MS), and ion chromatography (IC). A large number of oxygenated molecules are
identified, including oligomers containing up to six monomer units,
functionalized monomer and oligomers with carbonyl, carboxyl, and hydroxyl
groups, and small organic acid anions (e.g., formate, acetate, oxalate, and
malate). The average atomic oxygen-to-carbon (O / C) ratios of phenolic
aqSOA are in the range of 0.85–1.23, similar to those of low-volatility
oxygenated organic aerosol (LV-OOA) observed in ambient air. The aqSOA
compositions are overall similar for the same precursor, but the reactions
mediated by <sup>3</sup>C<sup>*</sup> are faster than · OH-mediated reactions and
produce more oligomers and hydroxylated species at the point when 50% of
the phenolic compound has reacted. Profiles determined using a thermodenuder
indicate that the volatility of phenolic aqSOA is influenced by both oligomer
content and O / C ratio. In addition, the aqSOA shows enhanced light
absorption in the UV–visible region, suggesting that aqueous-phase reactions
of phenols may contribute to formation of secondary brown carbon in the
atmosphere, especially in regions influenced by biomass burning. |
| first_indexed | 2024-04-14T08:09:43Z |
| format | Article |
| id | doaj.art-2be644c046d04dd3b4cbe25ccf5762f6 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-04-14T08:09:43Z |
| publishDate | 2014-12-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-2be644c046d04dd3b4cbe25ccf5762f62022-12-22T02:04:36ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242014-12-011424138011381610.5194/acp-14-13801-2014Chemical characterization of SOA formed from aqueous-phase reactions of phenols with the triplet excited state of carbonyl and hydroxyl radicalL. Yu0J. Smith1A. Laskin2C. Anastasio3J. Laskin4Q. Zhang5Department of Environmental Toxicology, University of California, 1 Shields Ave., Davis, CA 95616, USADepartment of Land, Air and Water Resources, University of California, 1 Shields Ave., Davis, CA 95616, USAEnvironmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352, USADepartment of Land, Air and Water Resources, University of California, 1 Shields Ave., Davis, CA 95616, USAPhysical Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USADepartment of Environmental Toxicology, University of California, 1 Shields Ave., Davis, CA 95616, USAPhenolic compounds, which are emitted in significant amounts from biomass burning, can undergo fast reactions in atmospheric aqueous phases to form secondary organic aerosol (aqSOA). In this study, we investigate the reactions of phenol (compound with formula C<sub>6</sub>H<sub>5</sub>OH)), guaiacol (2-methoxyphenol), and syringol (2,6-dimethoxyphenol) with two major aqueous-phase oxidants – the triplet excited states of an aromatic carbonyl (<sup>3</sup>C<sup>*</sup>) and hydroxyl radical (· OH). We thoroughly characterize the low-volatility species produced from these reactions and interpret their formation mechanisms using aerosol mass spectrometry (AMS), nanospray desorption electrospray ionization mass spectrometry (nano-DESI MS), and ion chromatography (IC). A large number of oxygenated molecules are identified, including oligomers containing up to six monomer units, functionalized monomer and oligomers with carbonyl, carboxyl, and hydroxyl groups, and small organic acid anions (e.g., formate, acetate, oxalate, and malate). The average atomic oxygen-to-carbon (O / C) ratios of phenolic aqSOA are in the range of 0.85–1.23, similar to those of low-volatility oxygenated organic aerosol (LV-OOA) observed in ambient air. The aqSOA compositions are overall similar for the same precursor, but the reactions mediated by <sup>3</sup>C<sup>*</sup> are faster than · OH-mediated reactions and produce more oligomers and hydroxylated species at the point when 50% of the phenolic compound has reacted. Profiles determined using a thermodenuder indicate that the volatility of phenolic aqSOA is influenced by both oligomer content and O / C ratio. In addition, the aqSOA shows enhanced light absorption in the UV–visible region, suggesting that aqueous-phase reactions of phenols may contribute to formation of secondary brown carbon in the atmosphere, especially in regions influenced by biomass burning.http://www.atmos-chem-phys.net/14/13801/2014/acp-14-13801-2014.pdf |
| spellingShingle | L. Yu J. Smith A. Laskin C. Anastasio J. Laskin Q. Zhang Chemical characterization of SOA formed from aqueous-phase reactions of phenols with the triplet excited state of carbonyl and hydroxyl radical Atmospheric Chemistry and Physics |
| title | Chemical characterization of SOA formed from aqueous-phase reactions of phenols with the triplet excited state of carbonyl and hydroxyl radical |
| title_full | Chemical characterization of SOA formed from aqueous-phase reactions of phenols with the triplet excited state of carbonyl and hydroxyl radical |
| title_fullStr | Chemical characterization of SOA formed from aqueous-phase reactions of phenols with the triplet excited state of carbonyl and hydroxyl radical |
| title_full_unstemmed | Chemical characterization of SOA formed from aqueous-phase reactions of phenols with the triplet excited state of carbonyl and hydroxyl radical |
| title_short | Chemical characterization of SOA formed from aqueous-phase reactions of phenols with the triplet excited state of carbonyl and hydroxyl radical |
| title_sort | chemical characterization of soa formed from aqueous phase reactions of phenols with the triplet excited state of carbonyl and hydroxyl radical |
| url | http://www.atmos-chem-phys.net/14/13801/2014/acp-14-13801-2014.pdf |
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