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| Titel |
Modelling the formation and composition of secondary organic aerosol from α- and β-pinene ozonolysis using MCM v3 |
| VerfasserIn |
M. E. Jenkin |
| 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 ; 4, no. 7 ; Nr. 4, no. 7 (2004-09-03), S.1741-1757 |
| Datensatznummer |
250002025
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| Publikation (Nr.) |
 copernicus.org/acp-4-1741-2004.pdf |
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| Zusammenfassung |
| The formation and detailed composition of secondary organic aerosol (SOA)
from the gas phase ozonolysis of α- and β-pinene has been
simulated using the Master Chemical Mechanism version 3
(MCM v3), coupled with a representation of gas-to-aerosol transfer of
semivolatile and involatile oxygenated products. A kinetics representation,
based on equilibrium absorptive partitioning of ca. 200 semivolatile
products, was found to provide an acceptable description of the final mass
concentrations observed in a number of reported laboratory and chamber
experiments, provided partitioning coefficients were increased by about two
orders of magnitude over those defined on the basis of estimated vapour
pressures. This adjustment is believed to be due, at least partially, to the
effect of condensed phase association reactions of the partitioning
products. Even with this adjustment, the simulated initial formation of SOA
was delayed relative to that observed, implying the requirement for the
formation of species of much lower volatility to initiate SOA formation. The
inclusion of a simplified representation of the formation and gas-to-aerosol
transfer of involatile dimers of 22 bi- and multifunctional carboxylic acids
(in addition to the absorptive partitioning mechanism) allowed a much
improved description of SOA formation for a wide range of conditions. The
simulated SOA composition recreates certain features of the product
distributions observed in a number of experimental studies, but implies an
important role for multifunctional products containing hydroperoxy groups
(i.e. hydroperoxides). This is particularly the case for experiments in
which 2-butanol is used to scavenge OH radicals, because
[HO2]/[RO2] ratios are elevated in such systems. The optimized
mechanism is used to calculate SOA yields from α- and β-pinene
ozonolysis in the presence and absence of OH scavengers,
and as a function of temperature. |
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