Hygroscopicity of aerosol particles at low temperatures. 1. New low-temperature H-TDMA instrument. setup and first applications
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Publication date
22.11.2001
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01A - Journal article
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Parent work
Environmental Science & Technology
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Series
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Volume
36
Issue / Number
1
Pages / Duration
55-62
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Publisher / Publishing institution
American Chemical Society
Place of publication / Event location
Washington, D.C.
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Abstract
A hygroscopicity tandem differential mobility analyzer (H-TDMA) is described that allows a fast and accurate determination of the water uptake by submicrometer aerosol particles at temperatures below 0 °C. To avoid volatilization of semivolatile particles, the humidification works without heating the gas stream, and the gas-phase composition is not changed during the analysis. The applied scanning mobility analysis allows a fast and accurate measurement of the humidogram, but care has to be taken with too high scanning velocities leading to artifacts in the particle size measurement. During a field campaign at a high-alpine site (Jungfraujoch, 3580 m above sea level), humidograms of free tropospheric particles were measured at T = −10 °C. The hygroscopic growth of these particles was characterized by monomodal growth distributions, which means that in the observed size range (dry particle diameters (Do) = 50−250 nm) the free tropospheric aerosol was to a large extent internally mixed. No distinct deliquescence was observed, indicating that the multicomponent aerosol particles are present in a liquid state even at a low relative humidity (RH) <10%. At RH 85%, average hygroscopic growth factors of 1.44, 1.49, and 1.53 were measured for Do = 50, 100, and 250 nm. The estimated soluble volume fraction of the particles in the observed size range was found to be 0.79, 0.86, and 0.91, respectively.
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550 - Geowissenschaften
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ISBN
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0013-936X
1520-5851
1520-5851
Language
English
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No
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Publication status
Published
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Peer review of the complete publication
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Closed
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Citation
WEINGARTNER, Ernest, Martin GYSEL und Urs BALTENSPERGER, 2001. Hygroscopicity of aerosol particles at low temperatures. 1. New low-temperature H-TDMA instrument. setup and first applications. Environmental Science & Technology. 22 November 2001. Bd. 36, Nr. 1, S. 55–62. DOI 10.1021/es010054o. Verfügbar unter: https://irf.fhnw.ch/handle/11654/46829