Hong Wu , Chao Peng , Tianyu Zhai , Jingcheng Deng , Peili Lu , Zhenliang Li , Yang Chen , Mi Tian , Zhier Bao , Xin Long , Fumo Yang , Chongzhi Zhai
{"title":"基于在线测量的重庆夏季和冬季棕碳气溶胶的光吸收特征及环境效应：二次形成的影响","authors":"Hong Wu , Chao Peng , Tianyu Zhai , Jingcheng Deng , Peili Lu , Zhenliang Li , Yang Chen , Mi Tian , Zhier Bao , Xin Long , Fumo Yang , Chongzhi Zhai","doi":"10.1016/j.atmosenv.2024.120843","DOIUrl":null,"url":null,"abstract":"<div><div>Light-absorbing organic carbon (i.e., brown carbon, BrC) significantly contributes to light absorption and radiative forcing in the atmospheric particles. However, the secondary formation of BrC and optical properties of secondary BrC are poorly understood. In this study, we analyzed and evaluated the light absorption and environmental effects of BrC and secondary BrC from July 1st to 31st, 2022 (summer) and January 20th to February 20th, 2023 (winter) in Chongqing. BrC and secondary BrC light absorption were estimated via a seven-wavelength aethalometer and the statistical approach. The average values of secondary BrC light absorption (Abs<sub>BrC,sec,λ</sub>) accounted for 46.2–56.5% of Abs<sub>BrC</sub>. Abs<sub>BrC,370</sub> and Abs<sub>BrC,sec,370</sub> were significantly higher during winter (26.2 ± 13.2 and 9.1 ± 5.2 Mm<sup>−1</sup> respectively) than that during summer (7.2 ± 4.1 and 5.2 ± 3.5 Mm<sup>−1</sup> respectively) (<em>p</em> < 0.001), suggesting secondary formation played an essential role in BrC. A diurnal cycle of Abs<sub>BrC,sec,370</sub> was explained by the photobleaching of light-absorbing chromophores under the oxidizing conditions in the daytime, and the formation of chromophores via aqueous reactions with NH<sub>4</sub><sup>+</sup> and NO<sub>x</sub> after sunset during winter. PSCF analysis showed that transport of anthropogenic emissions from the northeastern and southeastern areas of Chongqing was the important source of the secondary BrC in PP during winter. During winter, the average values of SFE<sub>BrC</sub> and SFE<sub>BrC,sec</sub> were 31.9 and 27.4 W g<sup>−1</sup> lower than that during summer (64.7 and 44.5 W g<sup>−1</sup>), respectively. In contrast, J[NO<sub>2</sub>] values of SFE<sub>BrC</sub> and SFE<sub>BrC,sec</sub> decreased by 23.3% and 8.7% during winter higher than that during summer (19.9% and 5.6%), indicating that BrC and secondary BrC cause substantial radiative effects and atmospheric photochemistry. Overall, this study is helpful in understanding the characterization and secondary formation of BrC and accurately evaluating the environmental effects of BrC in Chongqing.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"338 ","pages":"Article 120843"},"PeriodicalIF":4.2000,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Characteristics of light absorption and environmental effects of Brown carbon aerosol in Chongqing during summer and winter based on online measurement: Implications of secondary formation\",\"authors\":\"Hong Wu , Chao Peng , Tianyu Zhai , Jingcheng Deng , Peili Lu , Zhenliang Li , Yang Chen , Mi Tian , Zhier Bao , Xin Long , Fumo Yang , Chongzhi Zhai\",\"doi\":\"10.1016/j.atmosenv.2024.120843\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>Light-absorbing organic carbon (i.e., brown carbon, BrC) significantly contributes to light absorption and radiative forcing in the atmospheric particles. However, the secondary formation of BrC and optical properties of secondary BrC are poorly understood. In this study, we analyzed and evaluated the light absorption and environmental effects of BrC and secondary BrC from July 1st to 31st, 2022 (summer) and January 20th to February 20th, 2023 (winter) in Chongqing. BrC and secondary BrC light absorption were estimated via a seven-wavelength aethalometer and the statistical approach. The average values of secondary BrC light absorption (Abs<sub>BrC,sec,λ</sub>) accounted for 46.2–56.5% of Abs<sub>BrC</sub>. Abs<sub>BrC,370</sub> and Abs<sub>BrC,sec,370</sub> were significantly higher during winter (26.2 ± 13.2 and 9.1 ± 5.2 Mm<sup>−1</sup> respectively) than that during summer (7.2 ± 4.1 and 5.2 ± 3.5 Mm<sup>−1</sup> respectively) (<em>p</em> < 0.001), suggesting secondary formation played an essential role in BrC. A diurnal cycle of Abs<sub>BrC,sec,370</sub> was explained by the photobleaching of light-absorbing chromophores under the oxidizing conditions in the daytime, and the formation of chromophores via aqueous reactions with NH<sub>4</sub><sup>+</sup> and NO<sub>x</sub> after sunset during winter. PSCF analysis showed that transport of anthropogenic emissions from the northeastern and southeastern areas of Chongqing was the important source of the secondary BrC in PP during winter. During winter, the average values of SFE<sub>BrC</sub> and SFE<sub>BrC,sec</sub> were 31.9 and 27.4 W g<sup>−1</sup> lower than that during summer (64.7 and 44.5 W g<sup>−1</sup>), respectively. In contrast, J[NO<sub>2</sub>] values of SFE<sub>BrC</sub> and SFE<sub>BrC,sec</sub> decreased by 23.3% and 8.7% during winter higher than that during summer (19.9% and 5.6%), indicating that BrC and secondary BrC cause substantial radiative effects and atmospheric photochemistry. Overall, this study is helpful in understanding the characterization and secondary formation of BrC and accurately evaluating the environmental effects of BrC in Chongqing.</div></div>\",\"PeriodicalId\":250,\"journal\":{\"name\":\"Atmospheric Environment\",\"volume\":\"338 \",\"pages\":\"Article 120843\"},\"PeriodicalIF\":4.2000,\"publicationDate\":\"2024-09-26\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Atmospheric Environment\",\"FirstCategoryId\":\"93\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S1352231024005181\",\"RegionNum\":2,\"RegionCategory\":\"环境科学与生态学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"ENVIRONMENTAL SCIENCES\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Atmospheric Environment","FirstCategoryId":"93","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1352231024005181","RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENVIRONMENTAL SCIENCES","Score":null,"Total":0}
Characteristics of light absorption and environmental effects of Brown carbon aerosol in Chongqing during summer and winter based on online measurement: Implications of secondary formation
Light-absorbing organic carbon (i.e., brown carbon, BrC) significantly contributes to light absorption and radiative forcing in the atmospheric particles. However, the secondary formation of BrC and optical properties of secondary BrC are poorly understood. In this study, we analyzed and evaluated the light absorption and environmental effects of BrC and secondary BrC from July 1st to 31st, 2022 (summer) and January 20th to February 20th, 2023 (winter) in Chongqing. BrC and secondary BrC light absorption were estimated via a seven-wavelength aethalometer and the statistical approach. The average values of secondary BrC light absorption (AbsBrC,sec,λ) accounted for 46.2–56.5% of AbsBrC. AbsBrC,370 and AbsBrC,sec,370 were significantly higher during winter (26.2 ± 13.2 and 9.1 ± 5.2 Mm−1 respectively) than that during summer (7.2 ± 4.1 and 5.2 ± 3.5 Mm−1 respectively) (p < 0.001), suggesting secondary formation played an essential role in BrC. A diurnal cycle of AbsBrC,sec,370 was explained by the photobleaching of light-absorbing chromophores under the oxidizing conditions in the daytime, and the formation of chromophores via aqueous reactions with NH4+ and NOx after sunset during winter. PSCF analysis showed that transport of anthropogenic emissions from the northeastern and southeastern areas of Chongqing was the important source of the secondary BrC in PP during winter. During winter, the average values of SFEBrC and SFEBrC,sec were 31.9 and 27.4 W g−1 lower than that during summer (64.7 and 44.5 W g−1), respectively. In contrast, J[NO2] values of SFEBrC and SFEBrC,sec decreased by 23.3% and 8.7% during winter higher than that during summer (19.9% and 5.6%), indicating that BrC and secondary BrC cause substantial radiative effects and atmospheric photochemistry. Overall, this study is helpful in understanding the characterization and secondary formation of BrC and accurately evaluating the environmental effects of BrC in Chongqing.
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Atmospheric Environment has an open access mirror journal Atmospheric Environment: X, sharing the same aims and scope, editorial team, submission system and rigorous peer review.
Atmospheric Environment is the international journal for scientists in different disciplines related to atmospheric composition and its impacts. The journal publishes scientific articles with atmospheric relevance of emissions and depositions of gaseous and particulate compounds, chemical processes and physical effects in the atmosphere, as well as impacts of the changing atmospheric composition on human health, air quality, climate change, and ecosystems.
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