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Titel |
Terpenylic acid and related compounds: precursors for dimers in secondary organic aerosol from the ozonolysis of α- and β-pinene |
VerfasserIn |
F. Yasmeen, R. Vermeylen, R. Szmigielski, Y. Iinuma, O. Böge, H. Herrmann, W. Maenhaut, M. Claeys |
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. 19 ; Nr. 10, no. 19 (2010-10-05), S.9383-9392 |
Datensatznummer |
250008807
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Publikation (Nr.) |
copernicus.org/acp-10-9383-2010.pdf |
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Zusammenfassung |
In the present study, we have characterized the structure of a
higher-molecular weight (MW) 358 α- and β-pinene dimeric
secondary organic aerosol (SOA) product that received ample attention in
previous molecular characterization studies and has been elusive. Based on
mass spectrometric evidence for deprotonated molecules formed by electrospray
ionization in the negative ion mode and chemical considerations, it is
suggested that diaterpenylic acid is a key monomeric intermediate for dimers
of the ester type. It is proposed that cis-pinic acid is esterified
with the hydroxyl-containing diaterpenylic acid, which can be explained
through acid-catalyzed hydrolysis of the recently elucidated
lactone-containing terpenylic acid and/or diaterpenylic acid acetate, both
first-generation oxidation products. To a minor extent, higher-MW 358 and 344
diester products are formed containing other terpenoic acids as monomeric
units, i.e., diaterpenylic acid instead of cis-pinic acid, and
diaterebic acid instead of diaterpenylic acid. It is shown that the MW 358
diester and related MW 344 compounds, which can be regarded as processed SOA
products, also occur in ambient fine (PM2.5) rural aerosol collected at
night during the warm period of the 2006 summer field campaign conducted at
K-puszta, Hungary, a rural site with coniferous vegetation. This indicates
that, under ambient conditions, the higher-MW diesters are formed in the
particle phase over a longer time-scale than that required for
gas-to-particle partitioning of their monomeric precursors in laboratory
α-/β-pinene ozonolysis experiments. |
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