气候变化领域集成服务门户(CCPortal): Liquid-liquid phase separation and viscosity within secondary organic aerosol generated from diesel fuel vapors

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DOI	10.5194/acp-19-12515-2019
	Liquid-liquid phase separation and viscosity within secondary organic aerosol generated from diesel fuel vapors
	Song M.; MacLean A.M.; Huang Y.; Smith N.R.; Blair S.L.; Laskin J.; Laskin A.; DeRieux W.-S.W.; Li Y.; Shiraiwa M.; Nizkorodov S.A.; Bertram A.K.
发表日期	2019
ISSN	16807316
起始页码	12515
结束页码	12529
卷号	19 期号:19
英文摘要	Information on liquid-liquid phase separation (LLPS) and viscosity (or diffusion) within secondary organic aerosol (SOA) is needed to improve predictions of particle size, mass, reactivity, and cloud nucleating properties in the atmosphere. Here we report on LLPS and viscosities within SOA generated by the photooxidation of diesel fuel vapors. Diesel fuel contains a wide range of volatile organic compounds, and SOA generated by the photooxidation of diesel fuel vapors may be a good proxy for SOA from anthropogenic emissions. In our experiments, LLPS occurred over the relative humidity (RH) range of ∼ 70% to ∼ 100 %, resulting in an organic-rich outer phase and a water-rich inner phase. These results may have implications for predicting the cloud nucleating properties of anthropogenic SOA since the presence of an organic-rich outer phase at high-RH values can lower the supersaturation with respect to water required for cloud droplet formation. At ≤ 10%RH, the viscosity was ≥ 1×108 Pa s, which corresponds to roughly the viscosity of tar pitch. At 38 %-50%RH, the viscosity was in the range of 1×108 to 3×105 Pa s. These measured viscosities are consistent with predictions based on oxygen to carbon elemental ratio (O V C) and molar mass as well as predictions based on the number of carbon, hydrogen, and oxygen atoms. Based on the measured viscosities and the Stokes-Einstein relation, at ≤ 10%RH diffusion coefficients of organics within diesel fuel SOA is ≤ 5:4×10-17 cm2 s-1 and the mixing time of organics within 200 nm diesel fuel SOA particles (τmixing) is 50 h. These small diffusion coefficients and large mixing times may be important in laboratory experiments, where SOA is often generated and studied using low-RH conditions and on timescales of minutes to hours. At 38 %-50%RH, the calculated organic diffusion coefficients are in the range of 5:4×10-17 to 1:8×10-13 cm2 s-1 and calculated τmixing values are in the range of ∼ 0:01 h to ∼ 50 h. These values provide important constraints for the physicochemical properties of anthropogenic SOA. © 2019 Author(s). This work is distributed under the Creative Commons Attribution 4.0 License.
语种	英语
scopus关键词	aerosol; aerosol composition; anthropogenic source; diesel; liquid; nucleation; particle size; phase transition; photooxidation; physicochemical property; relative humidity; viscosity
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/144108
作者单位	Department of Earth and Environmental Sciences, Chonbuk National University, Jeollabuk-do, 54896, South Korea; Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1, Canada; Department of Chemistry, University of California Irvine, Irvine, CA 92697, United States; Department of Chemistry, Purdue University, West Lafayette, IN 47907, United States
推荐引用方式 GB/T 7714	Song M.,MacLean A.M.,Huang Y.,et al. Liquid-liquid phase separation and viscosity within secondary organic aerosol generated from diesel fuel vapors[J],2019,19(19).
APA	Song M..,MacLean A.M..,Huang Y..,Smith N.R..,Blair S.L..,...&Bertram A.K..(2019).Liquid-liquid phase separation and viscosity within secondary organic aerosol generated from diesel fuel vapors.Atmospheric Chemistry and Physics,19(19).
MLA	Song M.,et al."Liquid-liquid phase separation and viscosity within secondary organic aerosol generated from diesel fuel vapors".Atmospheric Chemistry and Physics 19.19(2019).