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| Titel |
On the link between hygroscopicity, volatility, and oxidation state of ambient and water-soluble aerosols in the southeastern United States |
| VerfasserIn |
K. M. Cerully, A. Bougiatioti, J. R. Hite, H. Guo, L. Xu, N. L. Ng, R. Weber, A. Nenes |
| 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 (2015-08-07), S.8679-8694 |
| Datensatznummer |
250119949
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| Publikation (Nr.) |
 copernicus.org/acp-15-8679-2015.pdf |
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| Zusammenfassung |
| The formation of secondary organic aerosols (SOAs) combined with the
partitioning of semivolatile organic components can impact numerous
aerosol properties including cloud condensation nuclei (CCN)
activity, hygroscopicity, and volatility. During the summer 2013
Southern Oxidant and Aerosol Study (SOAS) field campaign in a rural
site in the southeastern United States, a suite of instruments
including a CCN counter, a thermodenuder (TD), and a high-resolution
time-of-flight aerosol mass spectrometer (AMS) were used to measure
CCN activity, aerosol volatility, composition, and oxidation
state. Particles were either sampled directly from ambient or
through a particle-into-liquid sampler (PILS), allowing the
investigation of the water-soluble aerosol component. Ambient
aerosols exhibited size-dependent composition with larger particles
being more hygroscopic. The hygroscopicity of thermally denuded
aerosols was similar between ambient and PILS-generated aerosols and
showed limited dependence on volatilization. Results of AMS three-factor
positive matrix factorization (PMF) analysis for the PILS-generated
aerosols
showed that the most hygroscopic components are most likely the most
and the least volatile features of the aerosols. No clear
relationship was found between organic hygroscopicity and the
oxygen-to-carbon ratio; in fact, isoprene-derived organic aerosols
(isoprene-OAs) were found to be the most hygroscopic factor, while at
the same time being the least oxidized and likely most volatile of
all PMF factors. Considering the diurnal variation of each PMF
factor and its associated hygroscopicity, isoprene-OA and more-oxidized oxygenated organic aerosols are the prime
contributors to hygroscopicity and co-vary with less-oxidized oxygenated organic aerosols in a way that induces the observed
diurnal invariance in total organic hygroscopicity. Biomass burning
organic aerosols contributed little to aerosol
hygroscopicity, which is expected since there was little biomass
burning activity during the sampling period examined. |
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