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| Titel |
Kinetic regimes and limiting cases of gas uptake and heterogeneous reactions in atmospheric aerosols and clouds: a general classification scheme |
| VerfasserIn |
T. Berkemeier, A. J. Huisman, M. Ammann, M. Shiraiwa, T. Koop, 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 ; 13, no. 14 ; Nr. 13, no. 14 (2013-07-15), S.6663-6686 |
| Datensatznummer |
250018760
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| Publikation (Nr.) |
 copernicus.org/acp-13-6663-2013.pdf |
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| Zusammenfassung |
Heterogeneous reactions are important to atmospheric chemistry and
are therefore an area of intense research. In multiphase systems
such as aerosols and clouds, chemical reactions are usually strongly
coupled to a complex sequence of mass transport processes and
results are often not easy to interpret.
Here we present a systematic classification scheme for gas uptake by
aerosol or cloud particles which distinguishes two major regimes:
a reaction-diffusion regime and a mass transfer regime. Each of
these regimes includes four distinct limiting cases, characterised
by a dominant reaction location (surface or bulk) and a single
rate-limiting process: chemical reaction, bulk diffusion, gas-phase
diffusion or mass accommodation.
The conceptual framework enables efficient comparison of different
studies and reaction systems, going beyond the scope of previous
classification schemes by explicitly resolving interfacial transport
processes and surface reactions limited by mass transfer from the
gas phase. The use of kinetic multi-layer models instead of resistor
model approaches increases the flexibility and enables a broader
treatment of the subject, including cases which do not fit into the
strict limiting cases typical of most resistor model
formulations. The relative importance of different kinetic
parameters such as diffusion, reaction rate and accommodation
coefficients in this system is evaluated by a quantitative global
sensitivity analysis. We outline the characteristic features of each
limiting case and discuss the potential relevance of different
regimes and limiting cases for various reaction systems. In
particular, the classification scheme is applied to three different
datasets for the benchmark system of oleic acid reacting with
ozone in order to demonstrate utility and
highlight potential issues. In light of these results, future
directions of research needed to elucidate the multiphase chemical
kinetics in this and other reaction systems are discussed. |
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