Seasonal light absorption properties of water-soluble brown carbon in atmospheric fine particles in Nanjing, China

Chen, Yanfang; Ge, Xinlei; Chen, Hui; Xie, Xinchun; Chen, Yuntao; Wang, Jun Feng; Ye, Zhaolian; Bao, Mengying; Zhang, Yanlin; Chen, Mindong

doi:10.1016/j.atmosenv.2018.06.002

Cited by 100 publications

(63 citation statements)

References 93 publications

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“…Huang et al (2014) and Shen et al (2017) reported comparable AAE WS-BrC values (5.3-5.7) with no significant seasonal change at urban sites in Xi'an, suggesting common characteristics of BrC on a regional scale in the Guanzhong Basin of China. These results are comparable with the data reported in Guangzhou (5.3) (Liu et al, 2018), but much lower than those in Beijing (5.3-7.3) (Cheng et al, 2011;Yan et al, 2015b;Du et al, 2014) and Nanjing (6.7-7.3) (Chen et al, 2018). Moreover, comparable AAE values were reported for WS-BrC in Switzerland (3.8-5.1) (Moschos et al, 2018) and Nepal (4.2-5.6) (Wu et al, 2019;Kirillova et al, 2016), but higher AAE WS-BrC values were found in the southeastern US (7±1) (Hecobian et al, 2010), Los Angeles Basin (7.6±0.5) (Zhang et al, 2013) and South Korea (5.84-9.17) (Kim et al, 2016).…”

Section: Optical Absorption Characteristics Of Ws-brc and Wi-brcsupporting

confidence: 89%

“…2c, d), with the average MAC 365,WS-BrC being 1.00 (±0.18) m 2 g −1 in summer and 0.93 (±0.25) m 2 g −1 in winter (Table 1). As summarized in Table 2, the MAC 365,WS-BrC measured in this study, i.e., at a rural site in the Guanzhong Basin of China, is comparable to or lower than the values observed in Asian cities such Xi'an (Huang et al, 2018), Beijing (Cheng et al, 2011), Seoul (Kim et al, 2016) and New Delhi (Kirillova et al, 2014b) but obviously higher than those at the regional sites in the North China Plain (Teich et al, 2017) and the background site on the Tibetan Plateau (Xu et al, 2020). Moreover, significantly lower MAC 365,WS-BrC values were observed in the US, including in a SOA i : tracers of SOA formed from isoprene (SOAi) oxidation, i.e., the sum of 2-methylglyceric acid, 2-methylthreitol and 2-methylerythritol.…”

Section: Optical Absorption Characteristics Of Ws-brc and Wi-brcsupporting

confidence: 52%

“…China has been experiencing serious atmospheric pollution conditions in recent decades, and both model and field results showed elevated light absorption of BrC in most regions of China (Huang et al, 2018;Cheng et al, 2011;Yan et al, 2017;Li et al, 2016b) compared to developed countries such as the US (Hecobian et al, 2010;Washenfelder et al, 2015) and European countries (Mohr et al, 2013;Teich et al, 2017). However, BrC-related data are scarce in the Guanzhong Basin (Shen et al, 2017;Huang et al, 2018), which is one of the most polluted regions in China (van Donkelaar et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

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Optical properties and molecular compositions of water-soluble and water-insoluble brown carbon (BrC) aerosols in northwest China

Zhang

Wang

et al. 2020

Atmos. Chem. Phys.

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Abstract. Brown carbon (BrC) contributes significantly to aerosol light absorption and thus can affect the Earth's radiation balance and atmospheric photochemical processes. In this study, we examined the light absorption properties and molecular compositions of water-soluble (WS-BrC) and water-insoluble (WI-BrC) BrC in PM2.5 collected from a rural site in the Guanzhong Basin – a highly polluted region in northwest China. Both WS-BrC and WI-BrC showed elevated light absorption coefficients (Abs) in winter (4–7 times those in summer) mainly attributed to enhanced emissions from residential biomass burning (BB) for heating of homes. While the average mass absorption coefficients (MACs) at 365 nm (MAC365) of WS-BrC were similar between daytime and nighttime in summer (0.99±0.17 and 1.01±0.18 m2 g−1, respectively), the average MAC365 of WI-BrC was more than a factor of 2 higher during daytime (2.45±1.14 m2 g−1) than at night (1.18±0.36 m2 g−1). This difference was partly attributed to enhanced photochemical formation of WI-BrC species, such as oxygenated polycyclic aromatic hydrocarbons (OPAHs). In contrast, the MACs of WS-BrC and WI-BrC were generally similar in winter and both showed few diel differences. The Abs of wintertime WS-BrC correlated strongly with relative humidity, sulfate and NO2, suggesting that aqueous-phase reaction is an important pathway for secondary BrC formation during the winter season in northwest China. Nitrophenols on average contributed 2.44±1.78 % of the Abs of WS-BrC in winter but only 0.12±0.03 % in summer due to faster photodegradation reactions. WS-BrC and WI-BrC were estimated to account for 0.83±0.23 % and 0.53±0.33 %, respectively, of the total down-welling solar radiation in the ultraviolet (UV) range in summer, and 1.67±0.72 % and 2.07±1.24 %, respectively, in winter. The total absorption by BrC in the UV region was about 55 %–79 % relative to the elemental carbon (EC) absorption.

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Section: Optical Absorption Characteristics Of Ws-brc and Wi-brcsupporting

confidence: 89%

Section: Optical Absorption Characteristics Of Ws-brc and Wi-brcsupporting

confidence: 52%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Optical properties and molecular compositions of water-soluble and water-insoluble brown carbon (BrC) aerosols in northwest China

Zhang

Wang

et al. 2020

Atmos. Chem. Phys.

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“…Due to enhanced emission of BrC, average absλ=365nm of BrC found in winter was 49 ± 32 M/m for MeOH and 28 ± 16 M/m for WSOC, which were 9.5-and 8.1-fold higher than that in summer. This phenomenon was also observed in previous studies in Xi'an (Shen et al, 2017;Huang et al, 2018) and other areas of China (Du et al, 2014;Chen et al, 2018). Compared with other regions (Table 2), the absolute absλ=365nm values in Xi'an were slightly lower than that in Indo-Gangetic Plain, India (Satish et al, 2017;Bachi, 2016), but were considerably higher than that in Beijing, China (Du et al, 2014), US (Zhang et al, 2011) and Korea (Kim et al, 2016), suggesting that BrC pollution is more significant in Xi'an, a developing region in China.…”

Section: Seasonal Variations Of Light Absorption By Brcsupporting

confidence: 84%

The characteristics of atmospheric brown carbon in Xi'an, inland China: sources, size distributions and optical properties

Wu¹,

Wang²,

Li³

et al. 2019

Preprint

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Abstract. To investigate the characteristic of atmospheric brown carbon (BrC) in the semi-arid region of East Asia, PM2.5 and size-resolved particles in the urban atmosphere of Xi'an, inland China during the winter and summer of 2017 were collected and analyzed for optical properties and chemical compositions. Methanol extracts (MeOH-extracts) were more light-absorbing than water extracts (H2O- extracts) in the optical wavelength of 300&#8211;600&#8201;nm, and well correlated with nitrophenols, polycyclic aromatic hydrocarbons (PAHs) and oxygenated PAHs (R2&#8201;>&#8201;0.6). The light absorptions (abs&#955;=365nm) of H2O- extracts and MeOH-extracts in winter were 28&#8201;&#177;&#8201;16&#8201;M/m and 49&#8201;&#177;&#8201;32&#8201;M/m, respectively, which are about 10 times higher than those in summer, mainly due to the enhanced emissions from biomass burning for house heating. Water extracted BrC predominately occurred in the fine mode (<&#8201;2.1&#8201;&#181;m) during winter and summer, accounting for 81&#8201;% and 65&#8201;% of the total absorption of BrC, respectively. The light absorption and stable carbon isotope composition measurements showed an increasing ratio of abs&#955;=365nm-MeOH to abs&#955;=550nm-EC along with an enrichment of 13C in PM2.5 during the haze development, indicating an accumulation of secondarily formed BrC (e.g., nitrophenols) in aerosol aging process. PMF analysis showed that biomass burning, fossil fuel combustion, secondary formation, and, fugitive dust are the major sources of BrC in the city, accounting for 54.7&#8201;%, 19&#8201;%, 16.2&#8201;%, and 10&#8201;% of the total BrC, respectively.

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“…Comparison of MAE 365 in the WSOC fraction of source emission aerosols with the other studies. The references were listed as follows: Liu et al, 2018;Mo et al, 2018;Yan et al, 2015;Cheng et al, 2011;Cheng et al, 2016;Xie et al, 2019;Hecobian et al, 2010;Zhang et al, 2013;Park et al, 2018;Wu et al, 2019;Fan et al, 2016;Park and Yu, 2016;Chen et al, 2018. :…”

Section: Uv-vis Absorption Spectra and Eem Fluorescence Spectramentioning

confidence: 99%

Molecular compositions and optical properties of dissolved brown carbon in biomass burning, coal combustion, and vehicle emission aerosols illuminated by excitation–emission matrix spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry analysis

et al. 2020

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Abstract. Brown carbon (BrC) plays an essential impact on radiative forcing due to its ability to absorb sunlight. In this study, the optical properties and molecular characteristics of water-soluble and methanol-soluble organic carbon (OC; MSOC) emitted from the simulated combustion of biomass and coal fuels and vehicle emissions were investigated using ultraviolet–visible (UV–vis) spectroscopy, excitation–emission matrix (EEM) spectroscopy, and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) coupled with electrospray ionization (ESI). The results showed that these smoke aerosol samples from biomass burning (BB) and coal combustion (CC) had a higher mass absorption efficiency at 365 nm (MAE365) than vehicle emission samples. A stronger MAE365 value was also found in MSOC than water-soluble organic carbon (WSOC), indicating low polar compounds would possess a higher light absorption capacity. Parallel factor (PARAFAC) analysis identified six types of fluorophores (P1–6) in WSOC including two humic-like substances (HULIS-1) (P1 and P6), three protein-like substances (PLOM) (P2, P3, and P5), and one undefined substance (P4). HULIS-1 was mainly from aging vehicle exhaust particles; P2 was only abundant in BB aerosols; P3 was ubiquitous in all tested aerosols; P4 was abundant in fossil burning aerosols; and P5 was more intense in fresh vehicle exhaust particles. The MSOC chromophores (six components; C1–6) exhibited consistent characteristics with WSOC, suggesting the method could be used to indicate the origins of chromophores. FT-ICR mass spectra showed that CHO and CHON were the most abundant components of WSOC, but S-containing compounds appeared in a higher abundance in CC aerosols and vehicle emissions than BB aerosols, while considerably fewer S-containing compounds largely with CHO and CHON were detected in MSOC. The unique formulas of different sources in the van Krevelen (VK) diagram presented different molecular distributions. To be specific, BB aerosols with largely CHO and CHON had a medium H ∕ C and low O ∕ C ratio, while CC aerosols and vehicle emissions largely with S-containing compounds had an opposite H ∕ C and O ∕ C ratio. Moreover, the light absorption capacity of WSOC and MSOC was positively associated with the unsaturation degree and molecular weight in the source aerosols. The above results are potentially applicable to further studies on the EEM-based or molecular-characteristic-based source apportionment of chromophores in atmospheric aerosols.

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Seasonal light absorption properties of water-soluble brown carbon in atmospheric fine particles in Nanjing, China

Cited by 100 publications

References 93 publications

Optical properties and molecular compositions of water-soluble and water-insoluble brown carbon (BrC) aerosols in northwest China

Optical properties and molecular compositions of water-soluble and water-insoluble brown carbon (BrC) aerosols in northwest China

The characteristics of atmospheric brown carbon in Xi'an, inland China: sources, size distributions and optical properties

Molecular compositions and optical properties of dissolved brown carbon in biomass burning, coal combustion, and vehicle emission aerosols illuminated by excitation–emission matrix spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry analysis

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