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| Titel |
Uptake of NO3 and N2O5 to Saharan dust, ambient urban aerosol and soot: A relative rate study |
| VerfasserIn |
Mingjin Tang, Jim Thieser, Gerhard Schuster, John N. Cowley |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250037220
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| Zusammenfassung |
| The uptake of NO3 and N2O5 to Saharan dust, ambient aerosols and soot was investigated
using a novel and simple relative rate method with simultaneous detection of both NO3 and
N2O5. The use of cavity ring down spectroscopy to detect both trace gases enabled the
measurements to be carried out at low mixing ratios (< 500 pptv or 1Ã1010 molecules
cm-3). The uptake coefficient ratio, γ(NO3) / γ(N2O5), was determined to be 0.9±0.3 for
Saharan dust, independent of relative humidity and exposure time. Ambient (urban) aerosols
showed a very limited capacity to take up N2O5 but were reactive towards NO3 with γ(NO3)
/ γ(N2O5) >15. A value of γ(NO3) / γ(N2O5) -1.5 – 3 was obtained when using
candle generated soot. The relative rate obtained for Saharan dust can be placed on an
absolute basis using our recently determined value of γ(N2O5) = 1Ã10-2 to give
γ(NO3) = 9Ã10-3, which is significantly smaller than the present literature value.
With the present uptake coefficient, reaction with mineral dust will generally not
contribute significantly to NO3 loss in the atmosphere or to the nitration of mineral dust. |
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