Measurement report: Brown carbon aerosol in polluted urban air of the North China Plain – day–night differences in the chromophores and optical properties
<p>Brown carbon (BrC) aerosol is light-absorbing organic carbon that affects radiative forcing and atmospheric photochemistry. The BrC chromophoric composition and its linkage to optical properties at the molecular level, however, are still not well characterized. In this study, we investigate...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2023-12-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/23/15197/2023/acp-23-15197-2023.pdf |
| _version_ | 1797391433551839232 |
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| author | Y. Gong Y. Gong R.-J. Huang R.-J. Huang R.-J. Huang L. Yang L. Yang T. Wang W. Yuan W. Yuan W. Xu W. Cao Y. Wang Y. Wang Y. Li |
| author_facet | Y. Gong Y. Gong R.-J. Huang R.-J. Huang R.-J. Huang L. Yang L. Yang T. Wang W. Yuan W. Yuan W. Xu W. Cao Y. Wang Y. Wang Y. Li |
| author_sort | Y. Gong |
| collection | DOAJ |
| description | <p>Brown carbon (BrC) aerosol is light-absorbing organic carbon that affects radiative forcing and atmospheric photochemistry. The BrC chromophoric composition and its linkage to optical properties at the molecular level, however, are still not well characterized. In this study, we investigate the day–night differences in the chromophoric composition (38 species) and optical properties of water-soluble and water-insoluble BrC fractions (WS-BrC and WIS-BrC) in aerosol samples collected in Shijiazhuang, one of the most polluted cities in China. We found that the light absorption contribution of WS-BrC to total BrC at 365 nm was higher during the day (<span class="inline-formula">62±8</span> %) than during the night (<span class="inline-formula">47±26</span> %), which is in line with the difference in chromophoric polarity between daytime (more polar nitrated aromatics) and nighttime (more less-polar polycyclic aromatic hydrocarbons, PAHs). The high polarity and water solubility of BrC in the daytime suggests the enhanced contribution of secondary formation to BrC during the day. There was a decrease in the mass absorption efficiency of BrC from nighttime to daytime (<span class="inline-formula">2.88±0.24</span> vs. <span class="inline-formula">2.58±0.14</span> for WS-BrC and <span class="inline-formula">1.43±0.83</span> vs. <span class="inline-formula">1.02±0.49</span> m<span class="inline-formula"><sup>2</sup></span> g C<span class="inline-formula"><sup>−1</sup></span> for WIS-BrC, respectively). Large polycyclic aromatic hydrocarbons (PAHs) with four- to six-ring PAHs and nitrophenols contributed to 76.7 % of the total light absorption between 300–420 nm at nighttime, while nitrocatechols and two- to three-ring oxygenated PAHs accounted for 52.6 % of the total light absorption during the day. The total mass concentrations of the identified chromophores showed larger day–night difference during the low-pollution period (day-to-night ratio of 4.3) than during the high-pollution period (day-to-night ratio of 1.8). The large day–night difference in BrC composition and absorption, therefore, should be considered when estimating the sources, atmospheric processes, and impacts of BrC.</p> |
| first_indexed | 2024-03-08T23:33:29Z |
| format | Article |
| id | doaj.art-3de45b0391464e7b8039960f9ffa998d |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-03-08T23:33:29Z |
| publishDate | 2023-12-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-3de45b0391464e7b8039960f9ffa998d2023-12-14T08:59:09ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242023-12-0123151971520710.5194/acp-23-15197-2023Measurement report: Brown carbon aerosol in polluted urban air of the North China Plain – day–night differences in the chromophores and optical propertiesY. Gong0Y. Gong1R.-J. Huang2R.-J. Huang3R.-J. Huang4L. Yang5L. Yang6T. Wang7W. Yuan8W. Yuan9W. Xu10W. Cao11Y. Wang12Y. Wang13Y. Li14State Key Laboratory of Loess and Quaternary Geology, CAS Center for Excellence in Quaternary Science and Global Change, Institute of Earth Environment, Chinese Academy of Sciences, 710061 Xi'an, ChinaUniversity of Chinese Academy of Sciences, Beijing 100049, ChinaState Key Laboratory of Loess and Quaternary Geology, CAS Center for Excellence in Quaternary Science and Global Change, Institute of Earth Environment, Chinese Academy of Sciences, 710061 Xi'an, ChinaUniversity of Chinese Academy of Sciences, Beijing 100049, ChinaInstitute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, ChinaState Key Laboratory of Loess and Quaternary Geology, CAS Center for Excellence in Quaternary Science and Global Change, Institute of Earth Environment, Chinese Academy of Sciences, 710061 Xi'an, ChinaUniversity of Chinese Academy of Sciences, Beijing 100049, ChinaState Key Laboratory of Loess and Quaternary Geology, CAS Center for Excellence in Quaternary Science and Global Change, Institute of Earth Environment, Chinese Academy of Sciences, 710061 Xi'an, ChinaState Key Laboratory of Loess and Quaternary Geology, CAS Center for Excellence in Quaternary Science and Global Change, Institute of Earth Environment, Chinese Academy of Sciences, 710061 Xi'an, ChinaUniversity of Chinese Academy of Sciences, Beijing 100049, ChinaState Key Laboratory of Loess and Quaternary Geology, CAS Center for Excellence in Quaternary Science and Global Change, Institute of Earth Environment, Chinese Academy of Sciences, 710061 Xi'an, ChinaState Key Laboratory of Loess and Quaternary Geology, CAS Center for Excellence in Quaternary Science and Global Change, Institute of Earth Environment, Chinese Academy of Sciences, 710061 Xi'an, ChinaSchool of Geographical Sciences, Hebei Normal University, Shijiazhuang, ChinaState Key Joint Laboratory of Environmental Simulation and Pollution Control, Beijing, ChinaDepartment of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Taipa, Macau SAR 999078, China<p>Brown carbon (BrC) aerosol is light-absorbing organic carbon that affects radiative forcing and atmospheric photochemistry. The BrC chromophoric composition and its linkage to optical properties at the molecular level, however, are still not well characterized. In this study, we investigate the day–night differences in the chromophoric composition (38 species) and optical properties of water-soluble and water-insoluble BrC fractions (WS-BrC and WIS-BrC) in aerosol samples collected in Shijiazhuang, one of the most polluted cities in China. We found that the light absorption contribution of WS-BrC to total BrC at 365 nm was higher during the day (<span class="inline-formula">62±8</span> %) than during the night (<span class="inline-formula">47±26</span> %), which is in line with the difference in chromophoric polarity between daytime (more polar nitrated aromatics) and nighttime (more less-polar polycyclic aromatic hydrocarbons, PAHs). The high polarity and water solubility of BrC in the daytime suggests the enhanced contribution of secondary formation to BrC during the day. There was a decrease in the mass absorption efficiency of BrC from nighttime to daytime (<span class="inline-formula">2.88±0.24</span> vs. <span class="inline-formula">2.58±0.14</span> for WS-BrC and <span class="inline-formula">1.43±0.83</span> vs. <span class="inline-formula">1.02±0.49</span> m<span class="inline-formula"><sup>2</sup></span> g C<span class="inline-formula"><sup>−1</sup></span> for WIS-BrC, respectively). Large polycyclic aromatic hydrocarbons (PAHs) with four- to six-ring PAHs and nitrophenols contributed to 76.7 % of the total light absorption between 300–420 nm at nighttime, while nitrocatechols and two- to three-ring oxygenated PAHs accounted for 52.6 % of the total light absorption during the day. The total mass concentrations of the identified chromophores showed larger day–night difference during the low-pollution period (day-to-night ratio of 4.3) than during the high-pollution period (day-to-night ratio of 1.8). The large day–night difference in BrC composition and absorption, therefore, should be considered when estimating the sources, atmospheric processes, and impacts of BrC.</p>https://acp.copernicus.org/articles/23/15197/2023/acp-23-15197-2023.pdf |
| spellingShingle | Y. Gong Y. Gong R.-J. Huang R.-J. Huang R.-J. Huang L. Yang L. Yang T. Wang W. Yuan W. Yuan W. Xu W. Cao Y. Wang Y. Wang Y. Li Measurement report: Brown carbon aerosol in polluted urban air of the North China Plain – day–night differences in the chromophores and optical properties Atmospheric Chemistry and Physics |
| title | Measurement report: Brown carbon aerosol in polluted urban air of the North China Plain – day–night differences in the chromophores and optical properties |
| title_full | Measurement report: Brown carbon aerosol in polluted urban air of the North China Plain – day–night differences in the chromophores and optical properties |
| title_fullStr | Measurement report: Brown carbon aerosol in polluted urban air of the North China Plain – day–night differences in the chromophores and optical properties |
| title_full_unstemmed | Measurement report: Brown carbon aerosol in polluted urban air of the North China Plain – day–night differences in the chromophores and optical properties |
| title_short | Measurement report: Brown carbon aerosol in polluted urban air of the North China Plain – day–night differences in the chromophores and optical properties |
| title_sort | measurement report brown carbon aerosol in polluted urban air of the north china plain day night differences in the chromophores and optical properties |
| url | https://acp.copernicus.org/articles/23/15197/2023/acp-23-15197-2023.pdf |
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