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| Titel |
Simulating the detailed chemical composition of secondary organic aerosol formed on a regional scale during the TORCH 2003 campaign in the southern UK |
| VerfasserIn |
D. Johnson, S. R. Utembe, M. E. Jenkin |
| 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 ; 6, no. 2 ; Nr. 6, no. 2 (2006-02-08), S.419-431 |
| Datensatznummer |
250003416
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| Publikation (Nr.) |
 copernicus.org/acp-6-419-2006.pdf |
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| Zusammenfassung |
| Following on from the companion study (Johnson et al., 2006), a
photochemical trajectory model (PTM) has been used to simulate the chemical
composition of organic aerosol for selected events during the 2003 TORCH
(Tropospheric Organic Chemistry Experiment) field campaign. The PTM
incorporates the speciated emissions of 124 non-methane anthropogenic
volatile organic compounds (VOC) and three representative biogenic VOC, a
highly-detailed representation of the atmospheric degradation of these VOC,
the emission of primary organic aerosol (POA) material and the formation of
secondary organic aerosol (SOA) material. SOA formation was represented by
the transfer of semi- and non-volatile oxidation products from the gas-phase
to a condensed organic aerosol-phase, according to estimated thermodynamic
equilibrium phase-partitioning characteristics for around 2000 reaction
products. After significantly scaling all phase-partitioning coefficients,
and assuming a persistent background organic aerosol (both required in order
to match the observed organic aerosol loadings), the detailed chemical
composition of the simulated SOA has been investigated in terms of
intermediate oxygenated species in the Master Chemical Mechanism, version
3.1 (MCM v3.1). For the various case studies considered, 90% of the
simulated SOA mass comprises between ca. 70 and 100 multifunctional
oxygenated species derived, in varying amounts, from the photooxidation of
VOC of anthropogenic and biogenic origin. The anthropogenic contribution is
dominated by aromatic hydrocarbons and the biogenic contribution by α-
and β-pinene (which also constitute surrogates for other emitted
monoterpene species). Sensitivity in the simulated mass of SOA to changes in
the emission rates of anthropogenic and biogenic VOC has also been
investigated for 11 case study events, and the results have been compared to
the detailed chemical composition data. The role of accretion chemistry in
SOA formation, and its implications for the results of the present
investigation, is discussed. |
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