气候变化领域集成服务门户(CCPortal): Composition and sources of brown carbon aerosols in megacity Beijing during the winter of 2016

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DOI	10.1016/j.atmosres.2021.105773
	Composition and sources of brown carbon aerosols in megacity Beijing during the winter of 2016
	Li X.; Zhao Q.; Yang Y.; Zhao Z.; Liu Z.; Wen T.; Hu B.; Wang Y.; Wang L.; Wang G.
发表日期	2021
ISSN	0169-8095
卷号	262
英文摘要	Brown carbon (BrC) is a class of atmospheric particles that can strongly absorb visible and near-ultraviolet radiation, and it has an impact on global climate change. BrC is still poorly understood because of its complex sources and compositions. In this research, the characteristics of the light absorption, chromophores and sources of BrC were explored from PM2.5 collected in urban Beijing during the winter of 2016. Fairly high levels of the light absorption coefficient (Absλ) of methanol-extracted BrC and two categories of chromophores, i.e., nitro-aromatic compounds (NACs) and polycyclic aromatic hydrocarbons (PAHs), were found during haze episodes, with averages of 112.4 ± 8.31 M m−1 (λ=365 nm), 513 ± 370 ng m−3 and 429 ± 244 ng m−3, respectively, which were approximately 5 times higher than those during clean periods. Both methanol-extracted BrC and chromophores showed distinct diurnal variations that were twice as high during the nighttime than during the daytime. The average contributions of NACs and PAHs to the methanol-extracted BrC bulk light absorption at λ = 365 nm (Abs365) were 2.30% and 1.43%, respectively, which were approximately 4.6 and 3.9 times higher than the corresponding total organic mass fractions, respectively. Correlation analyses conducted on the NACs, Abs365, NO2 and relative humidity (RH) for the clean and haze episodes indicated that the aqueous-phase reaction with higher RH had a significant impact on the BrC during haze episodes in Beijing. The source apportionment of BrC by positive matrix factorization (PMF) indicated that coal combustion (39%), secondary formation (24%), and biomass burning (28%) were the major sources of BrC in the winter in Beijing. The contribution of secondary BrC sharply increased from 16% during clan periods to 29% during haze periods, indicating that secondary formation was an important source of BrC during haze episodes. The present research provides evidence that aqueous-phase transformation has a significant impact on BrC aerosols during haze periods in urban Beijing during the winter. © 2021
英文关键词	Aqueous-phase reaction; Brown carbon; Chromophores; Regional transport; Source apportionments
来源期刊	Atmospheric Research
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/236626
作者单位	Department of Chemistry, Capital Normal University, Beijing, 100048, China; College of Resource Environment and Tourism, Capital Normal University, Beijing, 100048, China; State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China; Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai, 200241, China
推荐引用方式 GB/T 7714	Li X.,Zhao Q.,Yang Y.,et al. Composition and sources of brown carbon aerosols in megacity Beijing during the winter of 2016[J],2021,262.
APA	Li X..,Zhao Q..,Yang Y..,Zhao Z..,Liu Z..,...&Wang G..(2021).Composition and sources of brown carbon aerosols in megacity Beijing during the winter of 2016.Atmospheric Research,262.
MLA	Li X.,et al."Composition and sources of brown carbon aerosols in megacity Beijing during the winter of 2016".Atmospheric Research 262(2021).