Chemical ageing and transformation of diffusivity in semi-solid multi-component organic aerosol particles

Pfrang, C., Shiraiwa, M. and Pöschl, U. (2011) Chemical ageing and transformation of diffusivity in semi-solid multi-component organic aerosol particles. Atmospheric Chemistry and Physics Discussions, 11 (4). pp. 13003-13033. ISSN 1680-7375 doi: 10.5194/acpd-11-13003-2011

Abstract/Summary

Recent experimental evidence underlines the importance of reduced diffusivity in amorphous semi-solid or glassy atmospheric aerosols. This paper investigates the impact of diffusivity on the ageing of multi-component reactive organic particles representative of atmospheric cooking aerosols. We apply and extend the recently developed KM-SUB model in a study of a 12-component mixture containing oleic and palmitoleic acids. We demonstrate that changes in the diffusivity may explain the evolution of chemical loss rates in ageing semi-solid particles, and we resolve surface and bulk processes under transient reaction conditions considering diffusivities altered by oligomerisation. This new model treatment allows prediction of the ageing of mixed organic multi-component aerosols over atmospherically relevant time scales and conditions. We illustrate the impact of changing diffusivity on the chemical half-life of reactive components in semisolid particles, and we demonstrate how solidification and crust formation at the particle surface can affect the chemical transformation of organic aerosols.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/19940
Identification Number/DOI	10.5194/acpd-11-13003-2011
Refereed	Yes
Divisions	Interdisciplinary centres and themes > Chemical Analysis Facility (CAF) > Optical Spectroscopy (CAF) Life Sciences > School of Chemistry, Food and Pharmacy > Department of Chemistry
Publisher	Copernicus Publications
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