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Titel |
Ground-based PTR-MS measurements of reactive organic compounds during the MINOS campaign in Crete, July–August 2001 |
VerfasserIn |
G. Salisbury, J. Williams, R. Holzinger, V. Gros, N. Mihalopoulos, M. Vrekoussis, R. Sarda-Estève, H. Berresheim, R. Kuhlmann, M. Lawrence, J. Lelieveld |
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 ; 3, no. 4 ; Nr. 3, no. 4 (2003-07-03), S.925-940 |
Datensatznummer |
250001129
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Publikation (Nr.) |
copernicus.org/acp-3-925-2003.pdf |
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Zusammenfassung |
This study presents measurements of acetonitrile, benzene, toluene, methanol and
acetone made using the proton-transfer-reaction mass spectrometry (PTR-MS)
technique at the Finokalia ground station in Crete during the Mediterranean INtensive
Oxidant Study (MINOS) in July-August 2001. Three periods during the campaign
with broadly consistent back trajectories are examined in detail. In the first, air was
advected from Eastern Europe without significant biomass burning influence (mean
acetonitrile mixing ratio 154 pmol/mol). In the second period, the sampled air masses
originated in Western Europe, and were advected approximately east-south-east,
before turning south-west over the Black Sea and north-western Turkey. The third
well-defined period included air masses advected from Eastern Europe passing east
and south of/over the Sea of Azov, and showed significant influence by
biomass burning (mean acetonitrile mixing ratio 436 pmol/mol), confirmed by satellite
pictures. The mean toluene:benzene ratios observed in the three campaign periods
described were 0.35, 0.37 and 0.22, respectively; the use of this quantity to determine
air mass age is discussed. Methanol and acetone were generally well-correlated both
with each other and with carbon monoxide throughout the campaign. Comparison of
the acetone and methanol measurements with the MATCH-MPIC model showed that
the model underestimated both species by a factor of 4, on average. The correlations
between acetone, methanol and CO implied that the relatively high levels of methanol
observed during MINOS were largely due to direct biogenic emissions, and also that
biogenic sources of acetone were highly significant during MINOS (~35%). This in
turn suggests that the model deficit in both species may be due, at least in part, to
missing biogenic emissions. |
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