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| Titel |
The impact of monoaromatic hydrocarbons on OH reactivity in the coastal UK boundary layer and free troposphere |
| VerfasserIn |
R. T. Lidster, J. F. Hamilton, J. D. Lee, A. C. Lewis, J. R. Hopkins, S. Punjabi, A. R. Rickard, J. C. Young |
| 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. 13 ; Nr. 14, no. 13 (2014-07-02), S.6677-6693 |
| Datensatznummer |
250118856
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| Publikation (Nr.) |
 copernicus.org/acp-14-6677-2014.pdf |
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| Zusammenfassung |
| Reaction with the hydroxyl radical (OH) is the dominant removal mechanism for
virtually all volatile organic compounds (VOCs) in the atmosphere; however,
it can be difficult to reconcile measured OH reactivity with known sinks.
Unresolved higher molecular weight VOCs contribute to OH sinks, of which
monoaromatics are potentially an important sub-class. A method based on
comprehensive two-dimensional gas chromatography coupled to time-of-flight
mass spectrometry (GC × GC-TOFMS) has been developed that extends
the degree with which larger VOCs can be individually speciated from whole
air samples (WAS). The technique showed excellent sensitivity, resolution and
good agreement with an established gas chromatography–flame
ionisation (GC-FID) method, for compounds amenable to
analysis on both instruments. Measurements have been made of VOCs within the
UK east coast marine boundary layer and free troposphere, using samples
collected from five aircraft flights in winter 2011. Ten monoaromatic
compounds with an array of different alkyl ring substituents have been
quantified, in addition to the simple aromatics, benzene, toluene, ethyl
benzene and Σm- and p-xylene. These additional
compounds were then included in constrained box model simulations of
atmospheric chemistry occurring at two UK rural and suburban field sites in
order to assess the potential impact of these larger monoaromatics species on
OH reactivity; they have been calculated to contribute an additional 2–6%
to the overall modelled OH loss rate, providing a maximum additional OH sink
of ~0.9 s−1. |
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