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| Titel |
Parameterization of N2O5 reaction probabilities on the surface of particles containing ammonium, sulfate, and nitrate |
| VerfasserIn |
J. M. Davis, P. V. Bhave, K. M. Foley |
| 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 ; 8, no. 17 ; Nr. 8, no. 17 (2008-09-05), S.5295-5311 |
| Datensatznummer |
250006365
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| Publikation (Nr.) |
 copernicus.org/acp-8-5295-2008.pdf |
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| Zusammenfassung |
| A parameterization was developed for the heterogeneous
reaction probability (γ) of N2O5 as a function of
temperature, relative humidity (RH), particle composition, and phase state, for
use in advanced air quality models. The reaction probabilities on aqueous
NH4HSO4, (NH4)2SO4, and NH4NO3 were
modeled statistically using data and uncertainty values compiled from seven
different laboratory studies. A separate regression model was fit to
laboratory data for dry NH4HSO4 and (NH4)2SO4
particles, yielding lower γ values than the corresponding aqueous
parameterizations. The regression equations reproduced 80% of the
laboratory data within a factor of two and 63% within a factor of 1.5. A
fixed value was selected for γ on ice-containing particles based on
a review of the literature. The combined parameterization was applied under
atmospheric conditions representative of the eastern United States using
3-dimensional fields of temperature, RH, sulfate, nitrate,
and ammonium. The resulting spatial distributions of γ were contrasted
with three other parameterizations that have been applied in air quality
models in the past and with atmospheric observational determinations of
γ. Our equations lay the foundation for future research that will
parameterize the suppression of γ when inorganic ammoniated particles
are mixed or coated with organic material. Our analyses draw attention to a
major uncertainty in the available laboratory data at high RH and highlight a
critical need for future laboratory measurements of γ at low temperature and
high RH to improve model simulations of N2O5 hydrolysis
during wintertime conditions. |
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