CCN activation of fumed silica aerosols mixed with soluble pollutants

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...

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Main Authors: M. Dalirian, H. Keskinen, L. Ahlm, A. Ylisirniö, S. Romakkaniemi, A. Laaksonen, A. Virtanen, I. Riipinen
Format: Article
Language:English
Published: Copernicus Publications 2015-04-01
Series:Atmospheric Chemistry and Physics
Online Access:http://www.atmos-chem-phys.net/15/3815/2015/acp-15-3815-2015.pdf
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author M. Dalirian
H. Keskinen
L. Ahlm
A. Ylisirniö
S. Romakkaniemi
A. Laaksonen
A. Virtanen
I. Riipinen
author_facet M. Dalirian
H. Keskinen
L. Ahlm
A. Ylisirniö
S. Romakkaniemi
A. Laaksonen
A. Virtanen
I. Riipinen
author_sort M. Dalirian
collection DOAJ
description 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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spelling doaj.art-ff1fc91db80b4680bec838b201a3d09d2022-12-22T03:15:51ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242015-04-011573815382910.5194/acp-15-3815-2015CCN activation of fumed silica aerosols mixed with soluble pollutantsM. Dalirian0H. Keskinen1L. Ahlm2A. Ylisirniö3S. Romakkaniemi4A. Laaksonen5A. Virtanen6I. Riipinen7Department of Environmental Science and Analytical Chemistry (ACES) and the Bolin Centre for Climate research, Stockholm University, Stockholm, SwedenDepartment of Applied Physics, University of Eastern Finland, Kuopio, FinlandDepartment of Environmental Science and Analytical Chemistry (ACES) and the Bolin Centre for Climate research, Stockholm University, Stockholm, SwedenDepartment of Applied Physics, University of Eastern Finland, Kuopio, FinlandDepartment of Applied Physics, University of Eastern Finland, Kuopio, FinlandDepartment of Applied Physics, University of Eastern Finland, Kuopio, FinlandDepartment of Applied Physics, University of Eastern Finland, Kuopio, FinlandDepartment of Environmental Science and Analytical Chemistry (ACES) and the Bolin Centre for Climate research, Stockholm University, Stockholm, SwedenParticle–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.http://www.atmos-chem-phys.net/15/3815/2015/acp-15-3815-2015.pdf
spellingShingle M. Dalirian
H. Keskinen
L. Ahlm
A. Ylisirniö
S. Romakkaniemi
A. Laaksonen
A. Virtanen
I. Riipinen
CCN activation of fumed silica aerosols mixed with soluble pollutants
Atmospheric Chemistry and Physics
title CCN activation of fumed silica aerosols mixed with soluble pollutants
title_full CCN activation of fumed silica aerosols mixed with soluble pollutants
title_fullStr CCN activation of fumed silica aerosols mixed with soluble pollutants
title_full_unstemmed CCN activation of fumed silica aerosols mixed with soluble pollutants
title_short CCN activation of fumed silica aerosols mixed with soluble pollutants
title_sort ccn activation of fumed silica aerosols mixed with soluble pollutants
url http://www.atmos-chem-phys.net/15/3815/2015/acp-15-3815-2015.pdf
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