DOI: 10.1002/jgrd.50285
论文题名: Droplet activation properties of organic aerosols observed at an urban site during CalNex-LA
作者: Mei F. ; Hayes P.L. ; Ortega A. ; Taylor J.W. ; Allan J.D. ; Gilman J. ; Kuster W. ; De Gouw J. ; Jimenez J.L. ; Wang J.
刊名: Journal of Geophysical Research Atmospheres
ISSN: 21698996
出版年: 2013
卷: 118, 期: 7 起始页码: 2903
结束页码: 2917
语种: 英语
Scopus关键词: Condensation
; Aerosol chemical composition
; Cloud condensation nuclei
; Diurnal variation
; Droplet activation
; Hydrophobic particles
; Least squares fit
; Organic oxidation
; Secondary organic aerosols
; Aerosols
; aerosol composition
; aerosol formation
; aerosol property
; cloud condensation nucleus
; diurnal variation
; droplet
; hygroscopicity
; oxidation
; photochemistry
; urban atmosphere
; California
; Pasadena
; United States
英文摘要: Size-resolved cloud condensation nuclei (CCN) spectra and aerosol chemical composition were characterized at an urban supersite in Pasadena, California, from 15 May to 4 June 2010, during the CalNex campaign. The derived hygroscopicity (kCCN ) of CCN-active particles with diameter between 97 and 165 nm ranged from 0.05 to 0.4. Diurnal variation showed a slight decrease of kCCN from 8:00 to 16:00 (from 0.24 to 0.20), which is attributed to increasing organics volume fraction resulted from secondary organic aerosol (SOA) formation. The derived hygroscopicity distribution and maximum activated fraction of the size selected particles were examined as functions of photochemical age. The result indicates that condensation of secondary species (e.g., SOA and sulfate) quickly converted hydrophobic particles to hydrophilic ones, and during daytime, nearly every particle became a CCN at ∼0.4% in just a few hours. Based on kCCN and aerosol chemical composition, the organic hygroscopicity (korg ) was derived, and ranged from 0.05 to 0.23 with an average value of 0.13, consistent with the results from earlier studies. The derived korg generally increased with the organic oxidation level, and most of the variation in korg could be explained by the variation of the organic O: C atomic ratio alone. The least squares fit of the data yielded korg = (0.83±0.06) ×(O:C) + (-0.19±0.02). Compared to previous results based on CCN measurements of laboratory generated aerosols, korg derived from measurements during the CalNex campaign exhibited stronger increase with O: C atomic ratio and therefore substantially higher values for organics with average O: C greater than 0.5. © 2013. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/63833
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: Brookhaven National Laboratory, Bldg. 815E, 75 Rutherford Dr, Upton, NY 11973, United States; Cooperative Institute for Research in Environmental Sciences, Boulder, CO, United States; Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, United States; School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester, United Kingdom; National Centre for Atmospheric Science, University of Manchester, Manchester, United Kingdom; NOAA Earth System Research Laboratory, Boulder, CO, United States; Pacific Northwest National Laboratory, Richland, WA, United States
Recommended Citation:
Mei F.,Hayes P.L.,Ortega A.,et al. Droplet activation properties of organic aerosols observed at an urban site during CalNex-LA[J]. Journal of Geophysical Research Atmospheres,2013-01-01,118(7)