气候变化领域集成服务门户(CCPortal): Potential underestimation of ambient brown carbon absorption based on the methanol extraction method and its impacts on source analysis

CCPortal

DOI	10.5194/acp-22-13739-2022
	Potential underestimation of ambient brown carbon absorption based on the methanol extraction method and its impacts on source analysis
	Xu, Zhenqi; Feng, Wei; Wang, Yicheng; Ye, Haoran; Wang, Yuhang; Liao, Hong; Xie, Mingjie
发表日期	2022
ISSN	1680-7316
EISSN	1680-7324
起始页码	13739
结束页码	13752
卷号	22 期号:20 页码:14
英文摘要	The methanol extraction method was widely applied to isolate organic carbon (OC) from ambient aerosols, followed by measurements of brown carbon (BrC) absorption. However, undissolved OC fractions will lead to underestimated BrC absorption. In this work, water, methanol (MeOH), MeOH / dichloromethane (MeOH /DCM, 1 : 1, v/v), MeOH /DCM (1 :2, v/v), tetrahydrofuran (THF), and N,N-dimethylformamide (DMF) were tested for extraction efficiencies of ambient OC, and the light absorption of individual solvent extracts was determined. Among the five solvents and solvent mixtures, DMF dissolved the highest fractions of ambient OC (up to similar to 95 %), followed by MeOH and MeOH / DCM mixtures (<90 %), and the DMF extracts had significantly (p <0.05) higher light absorption than other solvent extracts. This is because the OC fractions evaporating at higher temperatures (>280 degrees) are less soluble in MeOH (similar to 80 %) than in DMF (similar to 90 %) and contain stronger light-absorbing chromophores. Moreover, the light absorption of DMF and MeOH extracts of collocated aerosol samples in Nanjing showed consistent temporal variations in winter when biomass burning dominated BrC absorption, while the average light absorption of DMF extracts was more than 2 times greater than the MeOH extracts in late spring and summer. The average light absorption coefficient at 365 nm of DMF extracts was 30.7 % higher (p <0.01) than that of MeOH extracts. Source apportionment results indicated that the MeOH solubility of BrC associated with biomass burning, lubricating oil combustion, and coal combustion is similar to their DMF solubility. The BrC linked with unburned fossil fuels and polymerization processes of aerosol organics was less soluble in MeOH than in DMF, which was likely the main reason for the large difference in time series between MeOH and DMF extract absorption. These results highlight the importance of testing different solvents to investigate the structures and light absorption of BrC, particularly for the low-volatility fraction potentially originating from non-combustion sources.
学科领域	Environmental Sciences; Meteorology & Atmospheric Sciences
语种	英语
WOS研究方向	Environmental Sciences & Ecology ; Meteorology & Atmospheric Sciences
WOS记录号	WOS:000871564400001
来源期刊	ATMOSPHERIC CHEMISTRY AND PHYSICS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/273360
作者单位	Nanjing University of Information Science & Technology; University System of Georgia; Georgia Institute of Technology
推荐引用方式 GB/T 7714	Xu, Zhenqi,Feng, Wei,Wang, Yicheng,et al. Potential underestimation of ambient brown carbon absorption based on the methanol extraction method and its impacts on source analysis[J],2022,22(20):14.
APA	Xu, Zhenqi.,Feng, Wei.,Wang, Yicheng.,Ye, Haoran.,Wang, Yuhang.,...&Xie, Mingjie.(2022).Potential underestimation of ambient brown carbon absorption based on the methanol extraction method and its impacts on source analysis.ATMOSPHERIC CHEMISTRY AND PHYSICS,22(20),14.
MLA	Xu, Zhenqi,et al."Potential underestimation of ambient brown carbon absorption based on the methanol extraction method and its impacts on source analysis".ATMOSPHERIC CHEMISTRY AND PHYSICS 22.20(2022):14.