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| Titel |
Dinitrogen pentoxide (N2O5): A nighttime artefact in denuder measurements of nitric acid |
| VerfasserIn |
Gavin Phillips, Ulla Makkonen, Nicolas Sobanski, Gerhard Schuster, Hannele Hakola, John Crowley |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250078684
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| Zusammenfassung |
| A MARGA (Monitor for Reactive Gases and Aerosols, Metrohm Applikon BV, Netherlands)
wet-rotation denuder/steam-jet aerosol collector-ion chromatography system for reactive
gases and particles was deployed alongside a cavity ring-down spectroscopy (CRDS) system
for the measurement of dinitrogen pentoxide (N2O5) at the Taunus Observatory, Kleiner
Feldberg in SW Germany during August 2012.
The measurements show a strong indication that the well-known heterogeneous reaction,
N2O5(g) + H2O(l) - 2HNO3 results in the detection of a significant proportion of N2O5 as
NO3- in the MARGA system. This process, which is likely to affect analytical systems using
similar denuder technologies, results in the over estimation of HNO3 and will bias
assessments of chemistry in regions where N2O5 is a large proportion of Σ[HNO3 + 2N2O5].
The chemistry of N2O5 differs markedly from that of HNO3 not least as a significant
chemical loss of N2O5 in regions affected by particulate chloride is the formation of ClNO2,
a relatively unreactive photolabile species which regenerates NOx on photolysis in addition to
the production of Cl radical. The differing loss pathways of N2O5 and HNO3 may
result in the misdiagnoses of model output using denuder-based estimates of HNO3
to assess N-deposition. Denuder and filter-based methods should be assessed for
the size of the N2O5 bias and the likely result of using these techniques should be
estimated. |
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