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| Titel |
A qualitative comparison of secondary organic aerosol yields and composition from ozonolysis of monoterpenes at varying concentrations of NO2 |
| VerfasserIn |
D. C. Draper, D. K. Farmer, Y. Desyaterik, J. L. Fry |
| 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 ; 15, no. 21 ; Nr. 15, no. 21 (2015-11-05), S.12267-12281 |
| Datensatznummer |
250120142
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| Publikation (Nr.) |
 copernicus.org/acp-15-12267-2015.pdf |
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| Zusammenfassung |
| The effect of NO2 on secondary organic aerosol (SOA) formation from ozonolysis
of α-pinene, β-pinene, Δ3-carene, and limonene was
investigated using a dark flow-through reaction chamber. SOA mass yields were
calculated for each monoterpene from ozonolysis with varying NO2
concentrations. Kinetics modeling of the first-generation gas-phase chemistry
suggests that differences in observed aerosol yields for different NO2
concentrations are consistent with NO3 formation and subsequent
competition between O3 and NO3 to oxidize each monoterpene.
α-Pinene was the only monoterpene studied that showed a systematic
decrease in both aerosol number concentration and mass concentration with
increasing [NO2]. β-Pinene and Δ3-carene produced fewer
particles at higher [NO2], but both retained moderate mass yields.
Limonene exhibited both higher number concentrations and greater mass
concentrations at higher [NO2]. SOA from each experiment was collected and
analyzed by HPLC-ESI-MS, enabling comparisons between product distributions
for each system. In general, the systems influenced by NO3 oxidation
contained more high molecular weight products (MW > 400 amu), suggesting
the importance of oligomerization mechanisms in NO3-initiated SOA
formation. α-Pinene, which showed anomalously low aerosol mass yields
in the presence of NO2, showed no increase in these oligomer peaks,
suggesting that lack of oligomer formation is a likely cause of
α-pinene's near 0 % yields with NO3. Through direct comparisons
of mixed-oxidant systems, this work suggests that NO3 is likely to
dominate nighttime oxidation pathways in most regions with both biogenic and
anthropogenic influences. Therefore, accurately constraining SOA yields from
NO3 oxidation, which vary substantially with the volatile organic compound precursor, is
essential in predicting nighttime aerosol production. |
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