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| Titel |
Alpha-pinene oxidation by OH: simulations of laboratory experiments |
| VerfasserIn |
M. Capouet, J. Peeters, B. Nozi`ere, J.-F. Müller |
| 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 ; 4, no. 9/10 ; Nr. 4, no. 9/10 (2004-11-25), S.2285-2311 |
| Datensatznummer |
250001413
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| Publikation (Nr.) |
 copernicus.org/acp-4-2285-2004.pdf |
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| Zusammenfassung |
| This paper presents a state-of-the-art gas-phase mechanism for the
degradation of α-pinene by OH and its validation by box model
simulations of laboratory measurements. It is based on the near-explicit
mechanisms for the oxidation of α-pinene and pinonaldehyde by
OH proposed by Peeters and co-workers. The extensive set of
α-pinene photooxidation experiments performed in presence as well as
in absence of NO by Nozière et al. (1999a) is used to test the mechanism. The
comparison of the calculated vs measured concentrations as a function of time
shows that the levels of OH, NO, NO2 and light are well
reproduced in the model. Noting the large scatter in the experimental results
as well as the difficulty to retrieve true product yields from concentrations
data, a methodology is proposed for comparing the model and the data. The
model succeeds in reproducing the average apparent yields of pinonaldehyde,
acetone, total nitrates and total PANs in the experiments performed in
presence of NO. In absence of NO, pinonaldehyde is fairly well
reproduced, but acetone is largely underestimated.
The dependence of the product yields on the concentration of NO and
α-pinene is investigated, with a special attention on the influence of
the multiple competitions of reactions affecting the peroxy radicals in the
mechanism. We show that the main oxidation channels differ largely according
to photochemical conditions. E.g. the pinonaldehyde yield is estimated to be
about 10% in the remote atmosphere and up to 60% in very polluted areas. We
stress the need for additional theoretical/laboratory work to unravel the
chemistry of the primary products as well as the ozonolysis and
nitrate-initiated oxidation of α-pinene. |
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