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| Titel |
Simulation of aromatic SOA formation using the lumping model integrated with explicit gas-phase kinetic mechanisms and aerosol-phase reactions |
| VerfasserIn |
Y. Im, M. Jang, R. L. Beardsley |
| 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. 8 ; Nr. 14, no. 8 (2014-04-23), S.4013-4027 |
| Datensatznummer |
250118631
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| Publikation (Nr.) |
 copernicus.org/acp-14-4013-2014.pdf |
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| Zusammenfassung |
| The Unified Partitioning-Aerosol phase Reaction (UNIPAR) model has been
developed to predict the secondary organic aerosol (SOA) formation through
multiphase reactions. The model was evaluated with aromatic SOA data produced
from the photooxidation of toluene and 1,3,5-trimethylbenzene (135-TMB) under
various concentrations of NOx and SO2 using an outdoor
reactor (University of Florida Atmospheric PHotochemical Outdoor Reactor
(UF-APHOR) chamber). When inorganic species (sulfate, ammonium and water)
are present in aerosol, the prediction of both toluene SOA and 135-TMB SOA,
in which the oxygen-to-carbon (O : C) ratio is lower than 0.62, are approached
under the assumption of a complete organic/electrolyte-phase separation below
a certain relative humidity. An explicit gas-kinetic model was employed to
express gas-phase oxidation of aromatic hydrocarbons. Gas-phase products are
grouped based on their volatility (6 levels) and reactivity (5 levels) and
exploited to construct the stoichiometric coefficient (αi,j)
matrix, the set of parameters used to describe the concentrations of organic
compounds in multiphase. Weighting of the αi,j matrix as a function
of NOx improved the evaluation of NOx effects on aromatic
SOA. The total amount of organic matter (OMT) is predicted by two modules
in the UNIPAR model: OMP by a partitioning process and OMAR by
aerosol-phase reactions. The OMAR module predicts multiphase reactions of
organic compounds, such as oligomerization, acid-catalyzed reactions, and
organosulfate (OS) formation. The model reasonably simulates SOA formation
under various aerosol acidities, NOx concentrations, humidities and
temperatures. Furthermore, the OS fractions in the SOA predicted by the model
were in good agreement with the experimentally measured OS fractions. |
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