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| Titel |
Kinetic multi-layer model of aerosol surface and bulk chemistry (KM-SUB): the influence of interfacial transport and bulk diffusion on the oxidation of oleic acid by ozone |
| VerfasserIn |
M. Shiraiwa, C. Pfrang, U. Pöschl |
| 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 ; 10, no. 8 ; Nr. 10, no. 8 (2010-04-20), S.3673-3691 |
| Datensatznummer |
250008365
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| Publikation (Nr.) |
 copernicus.org/acp-10-3673-2010.pdf |
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| Zusammenfassung |
We present a novel kinetic multi-layer model that explicitly resolves mass
transport and chemical reaction at the surface and in the bulk of aerosol
particles (KM-SUB). The model is based on the PRA framework of
gas-particle interactions (Pöschl-Rudich-Ammann, 2007), and it
includes reversible adsorption, surface reactions and surface-bulk exchange
as well as bulk diffusion and reaction. Unlike earlier models, KM-SUB does
not require simplifying assumptions about steady-state conditions and radial
mixing. The temporal evolution and concentration profiles of volatile and
non-volatile species at the gas-particle interface and in the particle bulk
can be modeled along with surface concentrations and gas uptake
coefficients.
In this study we explore and exemplify the effects of bulk diffusion on the
rate of reactive gas uptake for a simple reference system, the ozonolysis of
oleic acid particles, in comparison to experimental data and earlier model
studies. We demonstrate how KM-SUB can be used to interpret and analyze
experimental data from laboratory studies, and how the results can be
extrapolated to atmospheric conditions. In particular, we show how
interfacial and bulk transport, i.e., surface accommodation, bulk
accommodation and bulk diffusion, influence the kinetics of the chemical
reaction. Sensitivity studies suggest that in fine air particulate matter
oleic acid and compounds with similar reactivity against ozone
(carbon-carbon double bonds) can reach chemical lifetimes of many hours only
if they are embedded in a (semi-)solid matrix with very low diffusion
coefficients (≤10−10 cm2 s−1).
Depending on the complexity of the investigated system, unlimited numbers of
volatile and non-volatile species and chemical reactions can be flexibly
added and treated with KM-SUB. We propose and intend to pursue the
application of KM-SUB as a basis for the development of a detailed master
mechanism of aerosol chemistry as well as for the derivation of simplified
but realistic parameterizations for large-scale atmospheric and climate
models. |
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