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| Titel |
A method to resolve the phase state of aerosol particles |
| VerfasserIn |
E. Saukko, H. Kuuluvainen, A. Virtanen |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 5, no. 1 ; Nr. 5, no. 1 (2012-01-30), S.259-265 |
| Datensatznummer |
250002320
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| Publikation (Nr.) |
 copernicus.org/amt-5-259-2012.pdf |
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| Zusammenfassung |
The phase state of atmospheric aerosols has an impact on their chemical aging
and their deliquescence and thus their ability to act as cloud condensation
nuclei (CCN). The phase change of particles can be induced by the
deliquescence or efflorescence of water or by chemical aging. Existing
methods, such as tandem differential mobility analysis rely on the size
change of particles related to the water uptake or release.
To address the need to study the phase change induced by mass-preserving and
nearly mass-preserving processes a new method has been developed. The method
relies on the physical impaction of particles on a smooth substrate and
subsequent counting of bounced particles by a condensation particle counter
(CPC). The connection between the bounce probability and physical properties
of particles is so far qualitative.
To evaluate the performance of this method, the phase state of ammonium
sulfate and levoglucosan, crystalline and amorphous solid, in the presence of
water vapor was studied. The results show a marked difference in particle
bouncing properties between substances – not only at the critical relative
humidity level, but also on the slope of the bouncing probability with
respect to humidity. This suggests that the method can be used to
differentiate between amorphous and crystalline substances as well as to
differentiate between liquid and solid phases. |
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