Seasonal and Day–Night Variations in Carbonaceous Aerosols and Their Light-Absorbing Properties in Guangzhou, China
Carbonaceous aerosols (CAs), including elemental carbon (EC) and organic carbon (OC), have become the dominant component in PM<sub>2.5</sub> in many Chinese cities, and it is imperative to address their spatiotemporal variations and sources in order to continually improve air quality. In...
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| Language: | English |
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MDPI AG
2023-10-01
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| Series: | Atmosphere |
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| Online Access: | https://www.mdpi.com/2073-4433/14/10/1545 |
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| author | Jiannan Su Runqi Zhang Bowen Liu Mengxue Tong Shaoxuan Xiao Xiaoyang Wang Qilong Zhao Wei Song Dilinuer Talifu Xinming Wang |
| author_facet | Jiannan Su Runqi Zhang Bowen Liu Mengxue Tong Shaoxuan Xiao Xiaoyang Wang Qilong Zhao Wei Song Dilinuer Talifu Xinming Wang |
| author_sort | Jiannan Su |
| collection | DOAJ |
| description | Carbonaceous aerosols (CAs), including elemental carbon (EC) and organic carbon (OC), have become the dominant component in PM<sub>2.5</sub> in many Chinese cities, and it is imperative to address their spatiotemporal variations and sources in order to continually improve air quality. In this study, the mass concentrations and light absorption properties of EC and OC in PM<sub>2.5</sub> were investigated at diverse sites in Guangzhou, in the winter of 2020 and the autumn of 2021, using the DRI Model 2015 thermal–optical carbon analyzer. The results showed that total EC and organic matter (OM = OC × 1.8) could account for nearly 30% of the PM<sub>2.5</sub> mass concentrations. Secondary production was the most important source for OC, with secondary OC (SOC) percentages in the OC as high as 72.8 ± 7.0% in autumn and 68.4 ± 13.1% in winter. Compared to those in 2015, OC and EC concentrations were reduced by 25.4% and 73.4% in 2021, highlighting the effectiveness of control measures in recent years. The absorption coefficient of brown carbon at 405 nm (b<sub>abs,BrC,405</sub>) decreased by over 40%, and the mass absorption coefficient (MAC) at 405 nm of total carbon (TC) decreased by over 30%. EC and OC concentrations and the light absorption of black carbon (b<sub>abs,BC,405</sub>) showed no significant diurnal differences in both autumn and winter mainly because the reduction in anthropogenic emissions at night was compensated by the lowering of the boundary layer. Differentially, b<sub>abs,BrC,405</sub> was significantly lower during daytime than at night in autumn, probably due to the daytime photobleaching effect. The sources of EC, OC, BC, and BrC were preliminarily diagnosed by their correlation with typical source markers. In autumn, b<sub>abs,BrC,405</sub> might be related to biomass burning and coal combustion, while b<sub>abs,BC,405</sub> were largely related to vehicle emissions and coal combustion. In winter, b<sub>abs,BrC,405</sub> was closely related to coal combustion. |
| first_indexed | 2024-03-10T21:27:21Z |
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| id | doaj.art-4a28c70e6f094a01af9a698f4b2a9285 |
| institution | Directory Open Access Journal |
| issn | 2073-4433 |
| language | English |
| last_indexed | 2024-03-10T21:27:21Z |
| publishDate | 2023-10-01 |
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| series | Atmosphere |
| spelling | doaj.art-4a28c70e6f094a01af9a698f4b2a92852023-11-19T15:36:32ZengMDPI AGAtmosphere2073-44332023-10-011410154510.3390/atmos14101545Seasonal and Day–Night Variations in Carbonaceous Aerosols and Their Light-Absorbing Properties in Guangzhou, ChinaJiannan Su0Runqi Zhang1Bowen Liu2Mengxue Tong3Shaoxuan Xiao4Xiaoyang Wang5Qilong Zhao6Wei Song7Dilinuer Talifu8Xinming Wang9State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, ChinaState Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, ChinaXinjiang Key Laboratory of Coal Clean Conversion & Chemical Engineering, College of Chemical Engineering, Xinjiang University, Urumqi 830017, ChinaState Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, ChinaState Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, ChinaState Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, ChinaXinjiang Key Laboratory of Coal Clean Conversion & Chemical Engineering, College of Chemical Engineering, Xinjiang University, Urumqi 830017, ChinaState Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, ChinaXinjiang Key Laboratory of Coal Clean Conversion & Chemical Engineering, College of Chemical Engineering, Xinjiang University, Urumqi 830017, ChinaState Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, ChinaCarbonaceous aerosols (CAs), including elemental carbon (EC) and organic carbon (OC), have become the dominant component in PM<sub>2.5</sub> in many Chinese cities, and it is imperative to address their spatiotemporal variations and sources in order to continually improve air quality. In this study, the mass concentrations and light absorption properties of EC and OC in PM<sub>2.5</sub> were investigated at diverse sites in Guangzhou, in the winter of 2020 and the autumn of 2021, using the DRI Model 2015 thermal–optical carbon analyzer. The results showed that total EC and organic matter (OM = OC × 1.8) could account for nearly 30% of the PM<sub>2.5</sub> mass concentrations. Secondary production was the most important source for OC, with secondary OC (SOC) percentages in the OC as high as 72.8 ± 7.0% in autumn and 68.4 ± 13.1% in winter. Compared to those in 2015, OC and EC concentrations were reduced by 25.4% and 73.4% in 2021, highlighting the effectiveness of control measures in recent years. The absorption coefficient of brown carbon at 405 nm (b<sub>abs,BrC,405</sub>) decreased by over 40%, and the mass absorption coefficient (MAC) at 405 nm of total carbon (TC) decreased by over 30%. EC and OC concentrations and the light absorption of black carbon (b<sub>abs,BC,405</sub>) showed no significant diurnal differences in both autumn and winter mainly because the reduction in anthropogenic emissions at night was compensated by the lowering of the boundary layer. Differentially, b<sub>abs,BrC,405</sub> was significantly lower during daytime than at night in autumn, probably due to the daytime photobleaching effect. The sources of EC, OC, BC, and BrC were preliminarily diagnosed by their correlation with typical source markers. In autumn, b<sub>abs,BrC,405</sub> might be related to biomass burning and coal combustion, while b<sub>abs,BC,405</sub> were largely related to vehicle emissions and coal combustion. In winter, b<sub>abs,BrC,405</sub> was closely related to coal combustion.https://www.mdpi.com/2073-4433/14/10/1545elemental carbonorganic carbonlight absorptiondiurnal variationsource |
| spellingShingle | Jiannan Su Runqi Zhang Bowen Liu Mengxue Tong Shaoxuan Xiao Xiaoyang Wang Qilong Zhao Wei Song Dilinuer Talifu Xinming Wang Seasonal and Day–Night Variations in Carbonaceous Aerosols and Their Light-Absorbing Properties in Guangzhou, China Atmosphere elemental carbon organic carbon light absorption diurnal variation source |
| title | Seasonal and Day–Night Variations in Carbonaceous Aerosols and Their Light-Absorbing Properties in Guangzhou, China |
| title_full | Seasonal and Day–Night Variations in Carbonaceous Aerosols and Their Light-Absorbing Properties in Guangzhou, China |
| title_fullStr | Seasonal and Day–Night Variations in Carbonaceous Aerosols and Their Light-Absorbing Properties in Guangzhou, China |
| title_full_unstemmed | Seasonal and Day–Night Variations in Carbonaceous Aerosols and Their Light-Absorbing Properties in Guangzhou, China |
| title_short | Seasonal and Day–Night Variations in Carbonaceous Aerosols and Their Light-Absorbing Properties in Guangzhou, China |
| title_sort | seasonal and day night variations in carbonaceous aerosols and their light absorbing properties in guangzhou china |
| topic | elemental carbon organic carbon light absorption diurnal variation source |
| url | https://www.mdpi.com/2073-4433/14/10/1545 |
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