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Titel |
Distribution of gaseous and particulate organic composition during dark α-pinene ozonolysis |
VerfasserIn |
M. Camredon, J. F. Hamilton, M. S. Alam, K. P. Wyche, T. Carr, I. R. White, P. S. Monks, A. R. Rickard, W. J. Bloss |
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 ; 10, no. 6 ; Nr. 10, no. 6 (2010-03-29), S.2893-2917 |
Datensatznummer |
250008263
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Publikation (Nr.) |
copernicus.org/acp-10-2893-2010.pdf |
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Zusammenfassung |
Secondary Organic Aerosol (SOA) affects atmospheric composition, air quality
and radiative transfer, however major difficulties are encountered in the
development of reliable models for SOA formation. Constraints on processes
involved in SOA formation can be obtained by interpreting the speciation and
evolution of organics in the gaseous and condensed phase simultaneously. In
this study we investigate SOA formation from dark α-pinene
ozonolysis with particular emphasis upon the mass distribution of gaseous
and particulate organic species. A detailed model for SOA formation is
compared with the results from experiments performed in the EUropean
PHOtoREactor (EUPHORE) simulation chamber, including on-line gas-phase
composition obtained from Chemical-Ionization-Reaction Time-Of-Flight
Mass-Spectrometry measurements, and off-line analysis of SOA samples
performed by Ion Trap Mass Spectrometry and Liquid Chromatography. The
temporal profile of SOA mass concentration is relatively well reproduced by
the model. Sensitivity analysis highlights the importance of the choice of
vapour pressure estimation method, and the potential influence of condensed
phase chemistry. Comparisons of the simulated gaseous- and condensed-phase
mass distributions with those observed show a generally good agreement. The
simulated speciation has been used to (i) propose a chemical structure for
the principal gaseous semi-volatile organic compounds and condensed monomer
organic species, (ii) provide evidence for the occurrence of recently
suggested radical isomerisation channels not included in the basic model,
and (iii) explore the possible contribution of a range of accretion
reactions occurring in the condensed phase. We find that oligomer formation
through esterification reactions gives the best agreement between the
observed and simulated mass spectra. |
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