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Titel |
Photodegradation of secondary organic aerosol generated from limonene oxidation by ozone studied with chemical ionization mass spectrometry |
VerfasserIn |
X. Pan, J. S. Underwood, J.-H. Xing, S. A. Mang, S. A. Nizkorodov |
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 ; 9, no. 12 ; Nr. 9, no. 12 (2009-06-15), S.3851-3865 |
Datensatznummer |
250007422
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Publikation (Nr.) |
copernicus.org/acp-9-3851-2009.pdf |
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Zusammenfassung |
Photodegradation of secondary organic aerosol (SOA)
prepared by ozone-initiated oxidation of D-limonene is studied with an action
spectroscopy approach, which relies on detection of volatile photoproducts
with chemical ionization mass-spectrometry as a function of the UV
irradiation wavelength. Efficient photodegradation is observed for a broad
range of ozone (0.1–300 ppm) and D-limonene (0.02–3 ppm) concentrations used
in the preparation of SOA. The observed photoproducts are dominated by
oxygenated C1-C3 compounds such as methanol, formic acid, acetaldehyde,
acetic acid, and acetone. The irradiation wavelength dependence of the
combined yield of the photoproducts closely tracks the absorption spectrum
of the SOA material suggesting that photodegradation is not limited to the
UV wavelengths. Kinetic simulations suggest that RO2+HO2/RO2 reactions represent the dominant route to photochemically
active carbonyl and peroxide species in the limonene SOA prepared in these
experiments. Similar photodegradation processes are likely to occur in
realistic SOA produced by OH- or O3-initiated oxidation of biogenic
volatile organic compounds in clean air. |
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