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| Titel |
Aqueous-phase oligomerization of methyl vinyl ketone through photooxidation – Part 2: Development of the chemical mechanism and atmospheric implications |
| VerfasserIn |
B. Ervens, P. Renard, S. Tlili, S. Ravier, J.-L. Clément, A. Monod |
| 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. 16 ; Nr. 15, no. 16 (2015-08-17), S.9109-9127 |
| Datensatznummer |
250119970
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| Publikation (Nr.) |
 copernicus.org/acp-15-9109-2015.pdf |
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| Zusammenfassung |
Laboratory experiments of efficient oligomerization from methyl vinyl ketone
(MVK) in the bulk aqueous phase were simulated in a box model. Kinetic data
are applied (if known) or fitted to the observed MVK decay and oligomer mass
increase. Upon model sensitivity studies, in which unconstrained rate
constants were varied over several orders of magnitude, a set of reaction
parameters was found that could reproduce laboratory data over a wide range
of experimental conditions. This mechanism is the first that comprehensively
describes such radical-initiated oligomer formation.
This mechanism was implemented into a multiphase box model that simulates
secondary organic aerosol (SOA) formation from isoprene, as a precursor of MVK and methacrolein (MACR)
in the aqueous and gas phases. While in laboratory experiments oxygen
limitation might occur and lead to accelerated oligomer formation, such
conditions are likely not met in the atmosphere. The comparison of predicted
oligomer formation shows that MVK and MACR likely do negligibly contribute
to total SOA as their solubilities are low and even reduced in aerosol water
due to ionic strength effects (Setchenov coefficients). Significant
contribution by oligomers to total SOA might only occur if a substantial
fraction of particulate carbon acts as oligomer precursors and/or if oxygen
solubility in aerosol water is strongly reduced due to salting-out effects. |
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