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| Titel |
Characterization of Organic Nitrate Formation in Limonene Secondary Organic Aerosol using High-Resolution Chemical Ionization Mass Spectrometry |
| VerfasserIn |
Cameron Faxon, Julia Hammes, Jianfei Peng, Mattias Hallquist, Ravi Pathak |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250136489
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| Publikation (Nr.) |
 EGU/EGU2016-17534.pdf |
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| Zusammenfassung |
| Previous work has shown that organic nitrates (RONO2) are prevalent in the boundary layer,
and can contribute significantly to secondary organic aerosol formation. Monoterpenes,
including limonene, have been shown to be precursors for the formation of these organic
nitrates. Limonene has two double bonds, either of which may be oxidized by NO3 or O3.
This leads to the generation of products that can subsequently condense or partition into the
particle phase, producing secondary organic aerosol. In order to further elucidate the particle
and gas phase product distribution of organic nitrates forming from the reactions of limonene
and the nitrate radical (NO3), a series of experiments were performed in the Gothenburg
Flow Reactor for Oxidation Studies at Low Temperatures (G-FROST), described by previous
work. N2O5 was used as the source for NO3 and NO2, and a characterized diffusion
source was used to introduce limonene into the flow reactor. All experiments were
conducted in the absence of light, and the concentration of limonene was increased
step-wise throughout each experiment to modify the ratio of N2O5to limonene. The
experiments were conducted such that both limonene- and N2O5-limited regimes were
present.
Gas and particle phase products were measured using an iodide High-Resolution
Time-of-Flight Mass Spectrometer (HR-ToF-CIMS) coupled to a Filter Inlet for Gases and
AEROsols (FIGAERO, and particle size and SOA mass concentrations were derived using a
Scanning Mobility Particle Sizer (SMPS). CIMS measurement techniques have previously
been employed for the measurement of organic nitrate products of such compounds using
multiple reagent ions. The use of this instrumentation allowed for the identification of
chemical formulas for gas and particle phase species. The findings from the experiments will
be presented in terms of the relative gas-particle partitioning of major products
and the effects of N2O5/limonene ratios on product distributions. Additionally, a
comparison of the distribution of the most prevalent reaction products relative to
the expected distribution derived using chemical kinetics simulations based on
the Master Chemical Mechanism (MCM) limonene mechanism will be discussed. |
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