Molecular compositions and optical properties of water-soluble brown carbon during the autumn and winter in Guangzhou, China

Tan, He; Wu, Yang Chang; Wang, Dian; Cai, Jing; Song, Jianzhong; Yu, Zhiqiang; Zeng, Xiangying; Peng, Ping’an

doi:10.1016/j.atmosenv.2022.119573

Cited by 11 publications

(20 citation statements)

References 71 publications

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“…The fluorescent components of this study from aerosol in urban regions were found to have similar distributions to those in Shidianzi background station (Li, Yue, et al., 2023), desert site (Erenhot) (Wen et al., 2021) during the winter campaign, rainwater in the Guanzhong basin (Li, Yu et al., 2022), and PM 2.5 in Mohanpur (Dey et al., 2021) during the summer campaign (Table S4 in Supporting Information ). In contrast, they differed from those in urban areas such as Guangzhou (Cao et al., 2023; He et al., 2023), Fengyang (Fan et al., 2021), Jinan (Wen et al., 2021), Xi’an (Chen, Hua, & Dyussenova, 2021), and Karachi (Tang et al., 2024). Furthermore, the relative abundances of fluorescent components varied across the five cities.…”

Section: Resultsmentioning

confidence: 97%

“…Two were HULIS components (P1 and P2) with spectra similar to C1 and C2, respectively (Figure 1b and Table S3 in Supporting Information , TCC > 0.95), and one was a phenolic‐like component (P3). These components are commonly detected in aerosols (He et al., 2023; Wu et al., 2019), and rainwater (Li, Fan, et al., 2020).…”

Section: Resultsmentioning

confidence: 99%

“…Laboratory and field experiments have shown that the PARAFAC components can reflect the sources and chemical properties of BrC (Chen et al., 2016; He et al., 2023; Yang et al., 2022). Previous studies have demonstrated that chemical reactions or “aging” in the atmosphere greatly alters the shapes of fluorescence spectra of emission sources, both by bleaching the source chromophores and by producing new chromophores (Bianco et al., 2014; Lee et al., 2013; Mu et al., 2021).…”

Section: Resultsmentioning

confidence: 99%

“…PARAFAC analysis generally identified independent components with very similar spectra (Murphy et al., 2013). These components exhibit distinct chemical characteristics (He et al., 2023; Jiang et al., 2022; Kellerman et al., 2015; Stubbins et al., 2014). In our recent study, we found that L‐HULIS, S‐HULIS, and phenolic‐like components have different molecular formulas, formation pathways, and precursors (Tang et al., 2024).…”

Section: Resultsmentioning

confidence: 99%

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Long‐Emission‐Wavelength Humic‐Like Component (L‐HULIS) as a Secondary Source Tracer of Brown Carbon in the Atmosphere

Tang,

Xu,

Zhao

et al. 2024

JGR Atmospheres

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The optical properties of secondary brown carbon (BrC) aerosols are poorly understood, hampering quantitative assessments of their impact. We propose a new method for estimating secondary source of BrC using excitation‐emission matrix (EEM) fluorescence spectroscopy, combined with parallel factor analysis (PARAFAC) and partial least squares regression (PLSR). Experiments were conducted on a collection of PM2.5 samples from urban areas in five Chinese cities during winter and summer. The humic‐like component with long‐emission wavelengths (L‐HULIS) was identified as a secondary source tracer of BrC. This was confirmed by correlating PARAFAC components with secondary organic aerosol tracers and molecular oxidation indices obtained from Fourier transform ion cyclotron resonance mass spectrometry analysis. Using L‐HULIS as a secondary tracer of BrC, it was determined that the contribution of secondary sources to water‐soluble BrC (WS‐BrC) in source emission samples is significantly smaller than in PM2.5 from five Chinese cities, supporting our method. In the five cities, secondary source derived via L‐HULIS contributes a dominant potion (80% ± 3.5%) of WS‐BrC at 365 nm during the summer, which is approximately twice as high as during the winter (45% ± 4.9%). Radiocarbon isotope (14C) analysis provides additional constraints to the sources of L‐HULIS‐derived secondary WS‐BrC in urban PM2.5, suggesting that aged biomass burning is the dominant contributor to secondary WS‐BrC in winter, and biogenic emission is dominant during summer. This study is the first report on identification of secondary sources of BrC using the fluorescence technique. It demonstrates the potential of this method in characterizing non‐fossil source secondary BrC in the atmosphere.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Long‐Emission‐Wavelength Humic‐Like Component (L‐HULIS) as a Secondary Source Tracer of Brown Carbon in the Atmosphere

Tang,

Xu,

Zhao

et al. 2024

JGR Atmospheres

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“…The Pearl River Delta (PRD) is one of the largest megacity clusters in the world, resulting from rapid economic growth and urbanization over the past few decades. Previous studies have investigated the light absorption of BrC in urban sites, including Guangzhou (Liu et al, 2018;Jiang et al, 2021;Mo et al, 2021;He et al, 2023), Hong Kong (Ma et al, 2019), and a semi-rural site, including Huaguoshan (Jiang et al, 2020). As far as we concerned, limited measurements of BrC have been conducted at regional atmospheric background stations in southern China, thus limiting the understanding of the impact of the city cluster.…”

mentioning

confidence: 99%

Seasonal changes in water-soluble brown carbon (BrC) at Nanling background station in South China

Zhang,

Tang,

Geng

et al. 2024

Front. Environ. Sci.

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Brown carbon (BrC) is an important light-absorbing component of organic carbon (OC), causing large uncertainty in aerosol radiative forcing evaluation and being related to health issues as well. Knowledge of BrC in an atmospheric background station is beneficial to understand its role in a changing climate. A year-long sampling campaign was conducted at Nanling background station to get a comprehensive knowledge of WS-BrC, a total of seventy-two PM2.5 samples throughout a year were used. Light absorption and fluorescence spectra of WSOC were analyzed synchronously using a fluorescence spectrophotometer. The low levels of PM2.5, OC, and elemental carbon (EC) conferred a background site. The optical properties of WS-BrC were characterized using excitation-emission matrix (EEM) fluorescence spectroscopy. The WS-BrC made a significant contribution (365 nm, 18% ± 10%) to total carbonaceous aerosol absorption. The mass absorption efficiency (MAE) of WS-BrC is 0.81 ± 0.34 m2 gC–1, and varies among seasons due to the different sources or atmospheric processing. Three EEM fluorescent components were identified by parallel factor (PAFAFAC) analysis, including two humic-like substances (HULIS, C1, C2), and one phenolic-like component. The HULIS components accounted for approximately 70% of the total fluorescence intensities. Primary combustion emissions showed enhanced activity during the winter and spring seasons, but there were no significant influences on WS-BrC in spring. Secondary sources contributed significantly to WS-BrC during winter, summer, and autumn (all exceeding 50%), except for spring. Photooxidation is a significant process in the formation of secondary WS-BrC in winter and autumn, but there may be another formation pathway in summer, i.e., the ammonia pathway. This study contributes to our understanding of BrC in the background atmosphere.

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Research progress on the characteristics, sources, and environmental and potential health effects of water-soluble organic compounds in atmospheric particulate matter

Wang,

Gao,

et al. 2024

Environ Sci Pollut Res

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Molecular compositions and optical properties of water-soluble brown carbon during the autumn and winter in Guangzhou, China

Cited by 11 publications

References 71 publications

Long‐Emission‐Wavelength Humic‐Like Component (L‐HULIS) as a Secondary Source Tracer of Brown Carbon in the Atmosphere

Long‐Emission‐Wavelength Humic‐Like Component (L‐HULIS) as a Secondary Source Tracer of Brown Carbon in the Atmosphere

Seasonal changes in water-soluble brown carbon (BrC) at Nanling background station in South China

Research progress on the characteristics, sources, and environmental and potential health effects of water-soluble organic compounds in atmospheric particulate matter

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