气候变化领域集成服务门户(CCPortal): Optical properties and molecular compositions of water-soluble and water-insoluble brown carbon (BrC) aerosols in northwest China

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DOI	10.5194/acp-20-4889-2020
	Optical properties and molecular compositions of water-soluble and water-insoluble brown carbon (BrC) aerosols in northwest China
	Li J.; Zhang Q.; Wang G.; Li J.; Wu C.; Liu L.; Wang J.; Jiang W.; Li L.; Fai Ho K.; Cao J.
发表日期	2020
ISSN	16807316
起始页码	4889
结束页码	4904
卷号	20 期号:8
英文摘要	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 1:01-0:18m2 g-1, respectively), the average MAC365 of WI-BrC was more than a factor of 2 higher during daytime (2:45-1:14m2 g-1) than at night (1:18-0:36m2 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 WIBrC 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. © 2020 Copernicus GmbH. All rights reserved.
关键词	absorption aerosol composition biomass burning brown carbon chemical composition molecular analysis optical property photochemistry photodegradation radiation balance China Lamprididae
语种	英语
来源机构	Atmospheric Chemistry and Physics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/132079
推荐引用方式 GB/T 7714	Li J.,Zhang Q.,Wang G.,et al. Optical properties and molecular compositions of water-soluble and water-insoluble brown carbon (BrC) aerosols in northwest China[J]. Atmospheric Chemistry and Physics,2020,20(8).
APA	Li J..,Zhang Q..,Wang G..,Li J..,Wu C..,...&Cao J..(2020).Optical properties and molecular compositions of water-soluble and water-insoluble brown carbon (BrC) aerosols in northwest China.,20(8).
MLA	Li J.,et al."Optical properties and molecular compositions of water-soluble and water-insoluble brown carbon (BrC) aerosols in northwest China".20.8(2020).