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| Titel |
The effect of temperature and water on secondary organic aerosol formation from ozonolysis of limonene, Δ³-carene and α-pinene |
| VerfasserIn |
A. M. Jönsson, M. Hallquist, E. Ljungström |
| 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 ; 8, no. 21 ; Nr. 8, no. 21 (2008-11-14), S.6541-6549 |
| Datensatznummer |
250006446
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| Publikation (Nr.) |
 copernicus.org/acp-8-6541-2008.pdf |
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| Zusammenfassung |
| The effect of reaction temperature and how water vapour influences the
formation of secondary organic aerosol (SOA) in ozonolysis of limonene,
Δ3-carene and α-pinene, both regarding number and mass
of particles, has been investigated by using a laminar flow reactor
(G-FROST). Experiments with cyclohexane and 2-butanol as OH scavengers were
compared to experiments without any scavenger. The reactions were conducted
in the temperature range between 298 and 243 K, and at relative humidities
between <10 and 80%. Results showed that there is still a scavenger
effect on number and mass concentrations at low temperatures between
experiments with and without an addition of an OH scavenger. This shows that
the OH chemistry is influencing the SOA formation also at these
temperatures. The overall temperature dependence on SOA formation is not as
strong as expected from partitioning theory. In some cases there is even a
positive temperature dependence that must be related to changes in the
chemical mechanism and/or reduced rates of secondary chemistry at low
temperatures. The precursor's α-pinene and Δ3-carene
exhibit a similar temperature dependence regarding both number and mass of
particles formed, whereas limonene shows a different dependence. The water
effect at low temperature could be explained by physical uptake and cluster
stabilisation. At higher temperatures, only a physical explanation is not
sufficient and the observations are in line with water changing the chemical
mechanism or reaction rates. The data presented adds to the understanding of
SOA contribution to new particle formation and atmospheric degradation
mechanisms. |
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