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| Titel |
Hygroscopic and phase separation properties of ammonium sulfate/organics/water ternary solutions |
| VerfasserIn |
M. A. Zawadowicz, S. R. Proud, S. S. Seppalainen, D. J. Cziczo |
| 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 ; 15, no. 15 ; Nr. 15, no. 15 (2015-08-13), S.8975-8986 |
| Datensatznummer |
250119962
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| Publikation (Nr.) |
 copernicus.org/acp-15-8975-2015.pdf |
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| Zusammenfassung |
| Atmospheric aerosol particles are often partially or completely composed of
inorganic salts, such as ammonium sulfate and sodium chloride, and therefore
exhibit hygroscopic properties. Many inorganic salts have well-defined
deliquescence and efflorescence points at which they take up and lose water,
respectively. Field measurements have shown that atmospheric aerosols are
not typically pure inorganic salt, instead, they often also contain organic
species. There is ample evidence from laboratory studies that suggests that
mixed particles exist in a phase-separated state, with an aqueous inorganic
core and organic shell. Although phase separation has not been measured in
situ, there is no reason it would not also take place in the atmosphere.
Here, we investigate the deliquescence and efflorescence points, phase
separation and ability to exchange gas-phase components of mixed organic and
inorganic aerosol using a flow tube coupled with FTIR (Fourier transform infrared) spectroscopy. Ammonium
sulfate aerosol mixed with organic polyols with different O : C ratios,
including 1,4-butanediol, glycerol, 1,2,6-hexanetriol, 1,2-hexanediol, and
1,5-pentanediol have been investigated. Those constituents correspond to
materials found in the atmosphere in great abundance and, therefore,
particles prepared in this study should mimic atmospheric mixed-phase
aerosol particles. Some results of this study tend to be in agreement with
previous microscopy experiments, but others, such as phase separation
properties of 1,2,6-hexanetriol, do not agree with previous work. Because
the particles studied in this experiment are of a smaller size than those
used in microscopy studies, the discrepancies found could be a size-related
effect. |
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