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| Titel |
Modeling secondary organic aerosol in an urban area: application to Paris, France |
| VerfasserIn |
F. Couvidat, Y. Kim, K. Sartelet, C. Seigneur, N. Marchand, J. Sciare |
| 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 ; 13, no. 2 ; Nr. 13, no. 2 (2013-01-23), S.983-996 |
| Datensatznummer |
250017611
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| Publikation (Nr.) |
 copernicus.org/acp-13-983-2013.pdf |
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| Zusammenfassung |
A secondary organic aerosol (SOA) model, H2O (Hydrophilic/Hydrophobic
Organic), is evaluated over the Paris area. This model treats the formation
of SOA with two kinds of surrogate species: hydrophilic species (which
condense preferentially on an aqueous phase) and hydrophobic species (which
condense only on an organic phase). These surrogates species are formed from
the oxidation in the atmosphere of volatile organic compounds (VOC) by
radicals (HO and NO3) and ozone. These VOC are either biogenic
(isoprene, monoterpenes and sesquiterpenes) or anthropogenic (mainly aromatic
compounds). This model includes the formation of aerosols from different
precursors (biogenic precursors, aromatics), and semi-volatile organic
compounds (SVOC) from traffic. The H2O aerosol model was incorporated
into the Polyphemus air quality modeling platform and applied to the Paris
area and evaluated by comparison to measurements performed during the
Megapoli campaign in July 2009.
The comparison to measurements in the suburbs and in the city center of Paris
shows that the model gives satisfactory results for both elemental carbon
(EC) and organic carbon (OC). However, the model gives a peak of OC
concentrations in the morning due to high emissions from traffic, which does
not appear in measurements. Uncertainties in the modeled temperature, which
can affect the gas-particle partitioning, in the partitioning of primary SVOC
or underestimation of primary organic aerosol (POA) evaporation by the model
could explain the differences between model and measurements. Moreover, using
a theoretical mechanism for the oxidation of primary SVOC and intermediate
volatility organic compounds (IVOC), POA concentrations were found to be
likely overestimated by models due to the use of simple partitioning
constants (which do not take into account the affinity of a compound with the
liquid aerosol solution) or due to the assumption that the organic aerosol
solution is a one-phase ideal solution. The organic aerosol in the city
center of Paris was found to be originating mostly from distant sources with
only 30 to 38% due to local sources. |
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