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| Titel |
The effect of varying levels of surfactant on the reactive uptake of N2O5 to aqueous aerosol |
| VerfasserIn |
V. F. McNeill, J. Patterson, G. M. Wolfe, J. A. Thornton |
| 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 ; 6, no. 6 ; Nr. 6, no. 6 (2006-05-22), S.1635-1644 |
| Datensatznummer |
250003828
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| Publikation (Nr.) |
 copernicus.org/acp-6-1635-2006.pdf |
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| Zusammenfassung |
| Recent observations have detected surface active organics in atmospheric
aerosols. We have studied the reaction of N2O5 on aqueous natural
seawater and NaCl aerosols as a function of sodium dodecyl sulfate (SDS)
concentration to test the effect of varying levels of surfactant on
gas-aerosol reaction rates. SDS was chosen as a proxy for naturally
occurring long chain monocarboxylic acid molecules, such as palmitic or
stearic acid, because of its solubility in water and well-characterized
surface properties. Experiments were performed using a newly constructed
aerosol flow tube coupled to a chemical ionization mass spectrometer for
monitoring the gas phase, and a differential mobility analyzer/condensation
particle counter for determining aerosol surface area. We find that the
presence of ~3.5wt% SDS in the aerosol, which corresponds to a
monolayer surface coverage of ~2×1014 molecules cm-2,
suppresses the N2O5 reaction probability, γN2O5, by
approximately a factor of ten, independent of relative humidity. Consistent
with this observation is a similar reduction in the rate of ClNO2
product generation measured simultaneously. However, the product yield
remains nearly constant under all conditions. The degree of suppression is
strongly dependent on SDS content in the aerosol, with no discernable effect
at 0.1wt% SDS, but significant suppression at what we predict to be
submonolayer coverages with 0.3–0.6wt% SDS on NaCl and natural
seawater aerosols, respectively. |
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