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| Titel |
Multi-generation gas-phase oxidation, equilibrium partitioning, and the formation and evolution of secondary organic aerosol |
| VerfasserIn |
C. D. Cappa, K. R. Wilson |
| 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 ; 12, no. 20 ; Nr. 12, no. 20 (2012-10-22), S.9505-9528 |
| Datensatznummer |
250011520
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| Publikation (Nr.) |
 copernicus.org/acp-12-9505-2012.pdf |
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| Zusammenfassung |
| A new model of secondary organic aerosol (SOA) formation is developed that
explicitly takes into account multi-generational oxidation as well as
fragmentation of gas-phase compounds, and assumes equilibrium gas-particle
partitioning. The model framework requires specification of a limited number
of tunable parameters to describe the kinetic evolution of SOA mass, the
average oxygen-to-carbon atomic ratio and the mean particle volatility as
oxidation proceeds. These parameters describe (1) the relationship between
oxygen content and volatility, (2) the probability of fragmentation and (3)
the amount of oxygen added per reaction. The time-evolution and absolute
value of the simulated SOA mass depends sensitively on all tunable
parameters. Of the tunable parameters, the mean O : C is most sensitive to the
oxygen/volatility relationship, exhibiting only a weak dependence on the
other relationships. The model mean particle O : C produced from a given
compound is primarily controlled by the number of carbon atoms comprising
the SOA precursor, with some sensitivity to the specified oxygen/volatility
relationship. The model is tested against laboratory measurements of
time-dependent SOA formation from the photooxidation of α-pinene and
n-pentadecane and performs well (after tuning). The model can also accurately
simulate the carbon-number dependence of aerosol yields previously observed
for oxidation of straight-chain alkanes. This model may provide a
generalized framework for the interpretation of laboratory SOA formation
experiments in which explicit consideration of multiple-generations of
products is required, which is true for all photo-oxidation experiments. |
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