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| Titel |
Volatile and intermediate volatility organic compounds in suburban Paris: variability, origin and importance for SOA formation |
| VerfasserIn |
W. Ait-Helal, A. Borbon, S. Sauvage, J. A. de Gouw, A. Colomb, V. Gros, F. Freutel, M. Crippa, C. Afif, U. Baltensperger, M. Beekmann, J.-F. Doussin, R. Durand-Jolibois, I. Fronval, N. Grand, T. Léonardis, M. López, V. Michoud, K. Miet, S. Perrier, A. S. H. Prévôt, J. Schneider, G. Siour, P. Zapf, N. Locoge |
| 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. 19 ; Nr. 14, no. 19 (2014-10-01), S.10439-10464 |
| Datensatznummer |
250119077
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| Publikation (Nr.) |
 copernicus.org/acp-14-10439-2014.pdf |
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| Zusammenfassung |
| Measurements of gaseous and particulate organic carbon were performed during
the MEGAPOLI experiments, in July 2009 and January–February 2010, at the
SIRTA observatory in suburban Paris. Measurements comprise primary and
secondary volatile organic compounds (VOCs), of both anthropogenic and
biogenic origins, including C12–C16 n-alkanes of intermediate
volatility (IVOCs), suspected to be efficient precursors of secondary organic
aerosol (SOA). The time series of gaseous carbon are generally consistent
with times series of particulate organic carbon at regional scale, and are
clearly affected by meteorology and air mass origin. Concentration levels of
anthropogenic VOCs in urban and suburban Paris were surprisingly low
(2–963 ppt) compared to other megacities worldwide and to rural continental
sites. Urban enhancement ratios of anthropogenic VOC pairs agree well between
the urban and suburban Paris sites, showing the regional extent of
anthropogenic sources of similar composition. Contrary to other primary
anthropogenic VOCs (aromatics and alkanes), IVOCs showed lower concentrations
in winter (< 5 ppt) compared to summer (13–27 ppt), which cannot
be explained by the gas-particle partitioning theory. Higher concentrations
of most oxygenated VOCs in winter (18–5984 ppt) suggest their dominant
primary anthropogenic origin. The respective role of primary anthropogenic
gaseous compounds in regional SOA formation was investigated by estimating
the SOA mass concentration expected from the anthropogenic VOCs and IVOCs
(I / VOCs) measured at SIRTA. From an integrated approach based on
emission ratios and SOA yields, 38 % of the SOA measured at SIRTA is
explained by the measured concentrations of I / VOCs, with a 2%
contribution by C12–C16 n-alkane IVOCs. From the results of an
alternative time-resolved approach, the average IVOC contribution to SOA
formation is estimated to be 7%, which is half of the average contribution
of the traditional aromatic compounds (15%). Both approaches, which are
based on in situ observations of particular I / VOCs, emphasize
the importance of the intermediate volatility compounds in the SOA formation,
and support previous results from chamber experiments and modeling studies.
They also support the need to make systematic the IVOCs' speciated
measurement during field campaigns. |
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