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| Titel |
Secondary organic aerosol yields of 12-carbon alkanes |
| VerfasserIn |
C. L. Loza, J. S. Craven, L. D. Yee, M. M. Coggon, R. H. Schwantes, M. Shiraiwa, X. Zhang, K. A. Schilling, N. L. Ng, M. R. Canagaratna, P. J. Ziemann, R. C. Flagan, J. H. Seinfeld |
| 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. 3 ; Nr. 14, no. 3 (2014-02-07), S.1423-1439 |
| Datensatznummer |
250118361
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| Publikation (Nr.) |
 copernicus.org/acp-14-1423-2014.pdf |
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| Zusammenfassung |
| Secondary organic aerosol (SOA) yields were measured for cyclododecane,
hexylcyclohexane, n-dodecane, and 2-methylundecane under high-NOx
conditions, in which alkyl proxy radicals (RO2) react primarily with
NO, and under low-NOx conditions, in which RO2 reacts
primarily with HO2. Experiments were run until 95–100% of the
initial alkane had reacted. Particle wall loss was evaluated as two limiting
cases using a new approach that requires only suspended particle number-size
distribution data and accounts for size-dependent particle wall losses and
condensation. SOA yield differed by a factor of 2 between the two limiting
cases, but the same trends among alkane precursors were observed for both
limiting cases. Vapor-phase wall losses were addressed through a modeling
study and increased SOA yield uncertainty by approximately 30%. SOA
yields were highest from cyclododecane under both NOx conditions. SOA
yields ranged from 3.3% (dodecane, low-NOx conditions) to 160%
(cyclododecane, high-NOx conditions). Under high-NOx
conditions, SOA yields increased from 2-methylundecane < dodecane
~ hexylcyclohexane < cyclododecane, consistent with previous studies.
Under low-NOx conditions, SOA yields increased from 2-methylundecane
~ dodecane < hexylcyclohexane < cyclododecane. The presence of
cyclization in the parent alkane structure increased SOA yields, whereas the
presence of branch points decreased SOA yields due to increased vapor-phase
fragmentation. Vapor-phase fragmentation was found to be more prevalent under
high-NOx conditions than under low-NOx conditions. For
different initial mixing ratios of the same alkane and same NOx
conditions, SOA yield did not correlate with SOA mass throughout SOA growth,
suggesting kinetically limited SOA growth for these systems. |
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