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Titel |
CCN activation of fumed silica aerosols mixed with soluble pollutants |
VerfasserIn |
M. Dalirian, H. Keskinen, L. Ahlm, A. Ylisirniö, S. Romakkaniemi, A. Laaksonen, A. Virtanen, I. Riipinen |
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. 7 ; Nr. 15, no. 7 (2015-04-09), S.3815-3829 |
Datensatznummer |
250119621
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Publikation (Nr.) |
copernicus.org/acp-15-3815-2015.pdf |
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Zusammenfassung |
Particle–water interactions of completely soluble or insoluble particles are
fairly well understood but less is known of aerosols consisting of mixtures
of soluble and insoluble components. In this study, laboratory measurements
were performed to investigate cloud condensation nuclei (CCN) activity of
silica particles mixed with ammonium sulfate (a salt), sucrose (a sugar)
and bovine serum albumin known as BSA (a protein). The agglomerated
structure of the silica particles was investigated using measurements with a
differential mobility analyser (DMA) and an aerosol particle mass analyser
(APM). Based on these data, the particles were assumed to be compact
agglomerates when studying their CCN activation capabilities. Furthermore,
the critical supersaturations of particles consisting of pure and mixed
soluble and insoluble compounds were explored using existing theoretical
frameworks. These results showed that the CCN activation of single-component
particles was in good agreement with Köhler- and adsorption theory based
models when the agglomerated structure was accounted for. For mixed
particles the CCN activation was governed by the soluble components, and the
soluble fraction varied considerably with particle size for our
wet-generated aerosols. Our results confirm the hypothesis that knowing the
soluble fraction is the key parameter needed for describing the CCN
activation of mixed aerosols, and highlight the importance of controlled
coating techniques for acquiring a detailed understanding of the CCN
activation of atmospheric insoluble particles mixed with soluble pollutants. |
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