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| Titel |
Biogenic SOA formation through gas-phase oxidation and gas-to-particle partitioning – a comparison between process models of varying complexity |
| VerfasserIn |
E. Hermansson, P. Roldin, A. Rusanen, D. Mogensen, N. Kivekäs, R. Väänänen, M. Boy, E. Swietlicki |
| 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 ; 14, no. 21 ; Nr. 14, no. 21 (2014-11-12), S.11853-11869 |
| Datensatznummer |
250119152
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| Publikation (Nr.) |
 copernicus.org/acp-14-11853-2014.pdf |
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| Zusammenfassung |
| Biogenic volatile organic compounds (BVOCs) emitted by vegetation play an
important role for aerosol mass loadings since the oxidation products of
these compounds can take part in the formation and growth of secondary
organic aerosols (SOA). The concentrations and properties of BVOCs and their
oxidation products in the atmosphere are poorly characterized, which leads to
high uncertainties in modeled SOA mass and properties. In this study, the
formation of SOA has been modeled along an air-mass trajectory over
northern European boreal forest using two aerosol dynamics box models where
the prediction of the condensable organics from the gas-phase oxidation of
BVOC is handled with schemes of varying complexity. The use of box model
simulations along an air-mass trajectory allows us to compare, under
atmospheric relevant conditions, different model parameterizations and their
effect on SOA formation. The result of the study shows that the modeled mass
concentration of SOA is highly dependent on the organic oxidation scheme used
to predict oxidation products. A near-explicit treatment of organic
gas-phase oxidation (Master Chemical Mechanism version 3.2) was compared to
oxidation schemes that use the volatility basis set (VBS) approach. The
resulting SOA mass modeled with different VBS schemes varies by a factor of
about 7 depending on how the first-generation oxidation products are
parameterized and how they subsequently age (e.g., how fast the gas-phase
oxidation products react with the OH radical, how they respond to temperature
changes, and if they are allowed to fragment during the aging process). Since
the VBS approach is frequently used in regional and global climate models due
to its relatively simple treatment of the oxidation products compared to
near-explicit oxidation schemes, a better understanding of the above-mentioned
processes is needed. Based on the results of this study, fragmentation
should be included in order to obtain a realistic SOA formation. Furthermore, compared to
the most commonly used VBS schemes, the near-explicit method produces less –
but more oxidized – SOA. |
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