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| Titel |
Relating hygroscopicity and composition of organic aerosol particulate matter |
| VerfasserIn |
J. Duplissy, P. F. DeCarlo, J. Dommen, M. R. Alfarra, A. Metzger, I. Barmpadimos, A. S. H. Prévôt, E. Weingärtner, T. Tritscher, M. Gysel, A. C. Aiken, J. L. Jimenez, M. R. Canagaratna, D. R. Worsnop, D. R. Collins, J. Tomlinson, U. Baltensperger |
| 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 ; 11, no. 3 ; Nr. 11, no. 3 (2011-02-10), S.1155-1165 |
| Datensatznummer |
250009298
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| Publikation (Nr.) |
 copernicus.org/acp-11-1155-2011.pdf |
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| Zusammenfassung |
| A hygroscopicity tandem differential mobility analyzer (HTDMA) was used to measure the water uptake (hygroscopicity) of secondary
organic aerosol (SOA) formed during the chemical and photochemical oxidation
of several organic precursors in a smog chamber. Electron ionization mass
spectra of the non-refractory submicron aerosol were simultaneously
determined with an aerosol mass spectrometer (AMS), and correlations between
the two different signals were investigated. SOA hygroscopicity was found to
strongly correlate with the relative abundance of the ion signal m/z 44
expressed as a fraction of total organic signal (f44). m/z 44 is due mostly
to the ion fragment CO2+ for all types of SOA systems studied, and
has been previously shown to strongly correlate with organic O/C for ambient
and chamber OA. The analysis was also performed on ambient OA from two field
experiments at the remote site Jungfraujoch, and the megacity Mexico City,
where similar results were found. A simple empirical linear relation between
the hygroscopicity of OA at subsaturated RH, as given by the hygroscopic
growth factor (GF) or "ϰorg" parameter, and f44 was determined and
is given by ϰorg = 2.2 × f44 − 0.13. This approximation can
be further verified and refined as the database for AMS and HTDMA
measurements is constantly being expanded around the world. The use of this
approximation could introduce an important simplification in the
parameterization of hygroscopicity of OA in atmospheric models, since
f44 is correlated with the photochemical age of an air mass. |
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