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DOI	10.5194/acp-20-11593-2020
	Optical properties and composition of viscous organic particles found in the Southern Great Plains
	Fraund M.; Bonanno D.J.; China S.; Pham D.Q.; Veghte D.; Weis J.; Kulkarni G.; Teske K.; Gilles M.K.; Laskin A.; Moffet R.C.
发表日期	2020
ISSN	1680-7316
起始页码	11593
结束页码	11606
卷号	20 期号:19
英文摘要	Atmospheric high-viscosity organic particles (HVOPs) were observed in samples of ambient aerosols collected in April and May 2016 in the Southern Great Plains of the United States. These particles were apportioned as either airborne soil organic particles (ASOPs) or tar balls (TBs) from biomass burning based on spetro-microscopic imaging and assessments of meteorological records of smoke and precipitation data. Regardless of their apportionment, the number fractions of HVOPs were positively correlated (R2 = 0.85) with increased values of absorption Ångström exponent (AAE) measured in situ for ambient aerosol at the site. Extending this correlation to 100 % HVOPs yields an AAE of 2.6, similar to previous literature reports of the class of light-absorbing organic particles known as brown carbon (BrC). One out of the three samples investigated had a significant number of ASOPs, while the other two samples contained TBs. Although there are chemical similarities between ASOPs and TBs, they can be distinguished based on composition inferred from near-edge absorption X-ray fine structure (NEXAFS) spectroscopy. ASOPs were distinguished from TBs based on their average −COOH/C=C and −COOH/COH peak ratios, with ASOPs having lower ratios. NEXAFS spectra of filtered soil organic brine particles nebulized from field samples of standing water deposited after rain were consistent with ASOPs when laboratory particles were generated by bubble bursting at the air–organic brine interface. However, particles generated by nebulizing the bulk volume of soil organic brine had a particle composition different from ASOPs. These observations are consistent with the raindrop generation mechanism responsible for ASOP emissions in the area of study. In contrast, nebulized samples carry with them higher fractions of soil inorganics dissolved in the bulk volume of soil brine, which are not aerosolized by the raindrop mechanism. Our results support the bubble bursting mechanism of particle generation during rainfall resulting in the ejection of soil organics into the atmosphere. In addition, our results show that ASOPs may only be atmospherically relevant during times when suitable emission conditions are met. © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License.
语种	英语
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/141076
作者单位	Department of Chemistry, University of the Pacific, Stockton, CA 95204, United States; Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory (PNNL), Richland, WA 99352, United States; Center for Electron Microscopy and Analysis, Ohio State University, Columbus, OH 43212, United States; Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States; Department of Chemistry, University of California, Berkeley, CA 94720, United States; Atmospheric Radiation Monitoring (Southern Great Plains Climate Research Facility), Billings, OK 74630, United States
推荐引用方式 GB/T 7714	Fraund M.,Bonanno D.J.,China S.,et al. Optical properties and composition of viscous organic particles found in the Southern Great Plains[J],2020,20(19).
APA	Fraund M..,Bonanno D.J..,China S..,Pham D.Q..,Veghte D..,...&Moffet R.C..(2020).Optical properties and composition of viscous organic particles found in the Southern Great Plains.Atmospheric Chemistry and Physics,20(19).
MLA	Fraund M.,et al."Optical properties and composition of viscous organic particles found in the Southern Great Plains".Atmospheric Chemistry and Physics 20.19(2020).