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| Titel |
Hygroscopic growth and critical supersaturations for mixed aerosol particles of inorganic and organic compounds of atmospheric relevance |
| VerfasserIn |
B. Svenningsson, J. Rissler, E. Swietlicki, M. Mircea, M. Bilde, M. C. Facchini, S. Decesari, S. Fuzzi, J. Zhou, J. Mønster, T. Rosenørn |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 6, no. 7 ; Nr. 6, no. 7 (2006-06-07), S.1937-1952 |
| Datensatznummer |
250003899
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| Publikation (Nr.) |
 copernicus.org/acp-6-1937-2006.pdf |
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| Zusammenfassung |
| The organic fraction of atmospheric aerosols contains a multitude of
compounds and usually only a small fraction can be identified and
quantified. However, a limited number of representative organic compounds
can be used to describe the water-soluble organic fraction. In this work,
initiated within the EU 5FP project SMOCC, four mixtures containing various
amounts of inorganic salts (ammonium sulfate, ammonium nitrate, and sodium
chloride) and three model organic compounds (levoglucosan, succinic acid and
fulvic acid) were studied. The interaction between water vapor and aerosol
particles was studied at different relative humidities: at subsaturation
using a hygroscopic tandem differential mobility analyzer (H-TDMA) and at
supersaturation using a cloud condensation nuclei spectrometer (CCN
spectrometer). Surface tensions as a function of carbon concentrations were
measured using a bubble tensiometer. Parameterizations of water activity as
a function of molality, based on hygroscopic growth, are given for the pure
organic compounds and for the mixtures, indicating van't Hoff factors around
1 for the organics. The Zdanovskii-Stokes-Robinson (ZSR) mixing rule was
tested on the hygroscopic growth of the mixtures and it was found to
adequately explain the hygroscopic growth for 3 out of 4 mixtures, when the
limited solubility of succinic acid is taken into account. One mixture
containing sodium chloride was studied and showed a pronounced deviation
from the ZSR mixing rule. Critical supersaturations calculated using the
parameterizations of water activity and the measured surface tensions were
compared with those determined experimentally. |
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