Aqueous secondary organic aerosol formation from the direct photosensitized oxidation of vanillin in the absence and presence of ammonium nitrate
<p>Vanillin (VL), a phenolic aromatic carbonyl abundant in biomass burning emissions, forms triplet excited states (<span class="inline-formula"><sup>3</sup></span>VL<span class="inline-formula"><sup>∗</sup></span>) under simu...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2022-01-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/22/273/2022/acp-22-273-2022.pdf |
| _version_ | 1819229261620314112 |
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| author | B. R. G. Mabato B. R. G. Mabato Y. Lyu Y. Lyu Y. Ji Y. Ji Y. J. Li D. D. Huang X. Li T. Nah C. H. Lam C. K. Chan C. K. Chan C. K. Chan |
| author_facet | B. R. G. Mabato B. R. G. Mabato Y. Lyu Y. Lyu Y. Ji Y. Ji Y. J. Li D. D. Huang X. Li T. Nah C. H. Lam C. K. Chan C. K. Chan C. K. Chan |
| author_sort | B. R. G. Mabato |
| collection | DOAJ |
| description | <p>Vanillin (VL), a phenolic aromatic carbonyl abundant in biomass burning emissions, forms triplet excited states (<span class="inline-formula"><sup>3</sup></span>VL<span class="inline-formula"><sup>∗</sup></span>) under
simulated sunlight leading to aqueous secondary organic aerosol (aqSOA)
formation. Nitrate and ammonium are among the main components of biomass
burning aerosols and cloud or fog water. Under atmospherically relevant cloud and fog conditions, solutions composed of either VL only or VL with ammonium nitrate were subjected to simulated sunlight irradiation to compare aqSOA formation via the direct photosensitized oxidation of VL in the absence and presence of ammonium nitrate. The reactions were characterized by examining the VL decay kinetics, product compositions, and light absorbance changes. Both conditions generated oligomers, functionalized monomers, and oxygenated ring-opening products, and ammonium nitrate promoted functionalization and nitration, likely due to its photolysis products (<span class="inline-formula"><sup><span class="Radical">⚫</span></sup></span>OH, <span class="inline-formula"><sup><span class="Radical">⚫</span></sup></span>NO<span class="inline-formula"><sub>2</sub></span>, and NO<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M6" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi/><mn mathvariant="normal">2</mn><mo>-</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="9pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="fd76842d31a9ea1dfefc20a8431a3f9b"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-273-2022-ie00001.svg" width="9pt" height="16pt" src="acp-22-273-2022-ie00001.png"/></svg:svg></span></span> or HONO). Moreover, a potential imidazole derivative observed in the presence of ammonium nitrate suggested that ammonium participated in the reactions. The majority of the most abundant products from both conditions were potential brown carbon (BrC) chromophores. The effects of oxygen (O<span class="inline-formula"><sub>2</sub>)</span>, pH, and reactants concentration and molar ratios on the reactions were also explored. Our findings show that O<span class="inline-formula"><sub>2</sub></span> plays an essential role in the reactions, and oligomer formation was enhanced at pH <span class="inline-formula"><i><</i>4</span>. Also, functionalization was dominant at low VL concentrations, whereas oligomerization was favored at high VL concentrations. Furthermore, oligomers and hydroxylated products were
detected from the oxidation of guaiacol (a non-carbonyl phenol) via VL
photosensitized reactions. Last, potential aqSOA formation pathways via
the direct photosensitized oxidation of VL in the absence and presence of
ammonium nitrate were proposed. This study indicates that the direct
photosensitized oxidation of VL may be an important aqSOA source in areas
influenced by biomass burning and underscores the importance of nitrate in
the aqueous-phase processing of aromatic carbonyls.</p> |
| first_indexed | 2024-12-23T11:10:22Z |
| format | Article |
| id | doaj.art-78e51527ab1d45748365fba6f677d2b6 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-23T11:10:22Z |
| publishDate | 2022-01-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-78e51527ab1d45748365fba6f677d2b62022-12-21T17:49:22ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242022-01-012227329310.5194/acp-22-273-2022Aqueous secondary organic aerosol formation from the direct photosensitized oxidation of vanillin in the absence and presence of ammonium nitrateB. R. G. Mabato0B. R. G. Mabato1Y. Lyu2Y. Lyu3Y. Ji4Y. Ji5Y. J. Li6D. D. Huang7X. Li8T. Nah9C. H. Lam10C. K. Chan11C. K. Chan12C. K. Chan13School of Energy and Environment, City University of Hong Kong, Kowloon, Hong Kong, ChinaCity University of Hong Kong Shenzhen Research Institute, Shenzhen, ChinaSchool of Energy and Environment, City University of Hong Kong, Kowloon, Hong Kong, ChinaCity University of Hong Kong Shenzhen Research Institute, Shenzhen, ChinaSchool of Energy and Environment, City University of Hong Kong, Kowloon, Hong Kong, ChinaCity University of Hong Kong Shenzhen Research Institute, Shenzhen, ChinaDepartment of Civil and Environmental Engineering, and Centre for Regional Oceans, Faculty of Science and Technology, University of Macau, Taipa, Macau 999078, ChinaState Environmental Protection Key Laboratory of Formation and Prevention of the Urban Air Pollution Complex, Shanghai Academy of Environmental Sciences, Shanghai 200233, ChinaInstitute of Mass Spectrometry and Atmospheric Environment, Jinan University, No. 601 Huangpu Avenue West, Guangzhou 510632, ChinaSchool of Energy and Environment, City University of Hong Kong, Kowloon, Hong Kong, ChinaSchool of Energy and Environment, City University of Hong Kong, Kowloon, Hong Kong, ChinaSchool of Energy and Environment, City University of Hong Kong, Kowloon, Hong Kong, ChinaCity University of Hong Kong Shenzhen Research Institute, Shenzhen, ChinaGuy Carpenter Asia-Pacific Climate Impact Center, City University of Hong Kong, Kowloon, Hong Kong, China<p>Vanillin (VL), a phenolic aromatic carbonyl abundant in biomass burning emissions, forms triplet excited states (<span class="inline-formula"><sup>3</sup></span>VL<span class="inline-formula"><sup>∗</sup></span>) under simulated sunlight leading to aqueous secondary organic aerosol (aqSOA) formation. Nitrate and ammonium are among the main components of biomass burning aerosols and cloud or fog water. Under atmospherically relevant cloud and fog conditions, solutions composed of either VL only or VL with ammonium nitrate were subjected to simulated sunlight irradiation to compare aqSOA formation via the direct photosensitized oxidation of VL in the absence and presence of ammonium nitrate. The reactions were characterized by examining the VL decay kinetics, product compositions, and light absorbance changes. Both conditions generated oligomers, functionalized monomers, and oxygenated ring-opening products, and ammonium nitrate promoted functionalization and nitration, likely due to its photolysis products (<span class="inline-formula"><sup><span class="Radical">⚫</span></sup></span>OH, <span class="inline-formula"><sup><span class="Radical">⚫</span></sup></span>NO<span class="inline-formula"><sub>2</sub></span>, and NO<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M6" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi/><mn mathvariant="normal">2</mn><mo>-</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="9pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="fd76842d31a9ea1dfefc20a8431a3f9b"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-273-2022-ie00001.svg" width="9pt" height="16pt" src="acp-22-273-2022-ie00001.png"/></svg:svg></span></span> or HONO). Moreover, a potential imidazole derivative observed in the presence of ammonium nitrate suggested that ammonium participated in the reactions. The majority of the most abundant products from both conditions were potential brown carbon (BrC) chromophores. The effects of oxygen (O<span class="inline-formula"><sub>2</sub>)</span>, pH, and reactants concentration and molar ratios on the reactions were also explored. Our findings show that O<span class="inline-formula"><sub>2</sub></span> plays an essential role in the reactions, and oligomer formation was enhanced at pH <span class="inline-formula"><i><</i>4</span>. Also, functionalization was dominant at low VL concentrations, whereas oligomerization was favored at high VL concentrations. Furthermore, oligomers and hydroxylated products were detected from the oxidation of guaiacol (a non-carbonyl phenol) via VL photosensitized reactions. Last, potential aqSOA formation pathways via the direct photosensitized oxidation of VL in the absence and presence of ammonium nitrate were proposed. This study indicates that the direct photosensitized oxidation of VL may be an important aqSOA source in areas influenced by biomass burning and underscores the importance of nitrate in the aqueous-phase processing of aromatic carbonyls.</p>https://acp.copernicus.org/articles/22/273/2022/acp-22-273-2022.pdf |
| spellingShingle | B. R. G. Mabato B. R. G. Mabato Y. Lyu Y. Lyu Y. Ji Y. Ji Y. J. Li D. D. Huang X. Li T. Nah C. H. Lam C. K. Chan C. K. Chan C. K. Chan Aqueous secondary organic aerosol formation from the direct photosensitized oxidation of vanillin in the absence and presence of ammonium nitrate Atmospheric Chemistry and Physics |
| title | Aqueous secondary organic aerosol formation from the direct photosensitized oxidation of vanillin in the absence and presence of ammonium nitrate |
| title_full | Aqueous secondary organic aerosol formation from the direct photosensitized oxidation of vanillin in the absence and presence of ammonium nitrate |
| title_fullStr | Aqueous secondary organic aerosol formation from the direct photosensitized oxidation of vanillin in the absence and presence of ammonium nitrate |
| title_full_unstemmed | Aqueous secondary organic aerosol formation from the direct photosensitized oxidation of vanillin in the absence and presence of ammonium nitrate |
| title_short | Aqueous secondary organic aerosol formation from the direct photosensitized oxidation of vanillin in the absence and presence of ammonium nitrate |
| title_sort | aqueous secondary organic aerosol formation from the direct photosensitized oxidation of vanillin in the absence and presence of ammonium nitrate |
| url | https://acp.copernicus.org/articles/22/273/2022/acp-22-273-2022.pdf |
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