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| Titel |
Secondary aerosol formation from atmospheric reactions of aliphatic amines |
| VerfasserIn |
S. M. Murphy, A. Sorooshian, J. H. Kroll, N. L. Ng, P. Chhabra, C. Tong, J. D. Surratt, E. Knipping, R. C. Flagan, J. H. Seinfeld |
| 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 ; 7, no. 9 ; Nr. 7, no. 9 (2007-05-08), S.2313-2337 |
| Datensatznummer |
250004952
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| Publikation (Nr.) |
 copernicus.org/acp-7-2313-2007.pdf |
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| Zusammenfassung |
| Although aliphatic amines have been detected in
both urban and rural atmospheric aerosols, little is known about the
chemistry leading to particle formation or the potential aerosol yields from
reactions of gas-phase amines. We present here the first systematic study of
aerosol formation from the atmospheric reactions of amines. Based on
laboratory chamber experiments and theoretical calculations, we evaluate
aerosol formation from reaction of OH, ozone, and nitric acid with
trimethylamine, methylamine, triethylamine, diethylamine, ethylamine, and
ethanolamine. Entropies of formation for alkylammonium nitrate salts are
estimated by molecular dynamics calculations enabling us to estimate
equilibrium constants for the reactions of amines with nitric acid. Though
subject to significant uncertainty, the calculated dissociation equilibrium
constant for diethylammonium nitrate is found to be sufficiently small to
allow for its atmospheric formation, even in the presence of ammonia which
competes for available nitric acid. Experimental chamber studies indicate
that the dissociation equilibrium constant for triethylammonium nitrate is
of the same order of magnitude as that for ammonium nitrate. All amines
studied form aerosol when photooxidized in the presence of NOx with the
majority of the aerosol mass present at the peak of aerosol growth
consisting of aminium (R3NH+) nitrate salts, which repartition
back to the gas phase as the parent amine is consumed. Only the two tertiary
amines studied, trimethylamine and triethylamine, are found to form
significant non-salt organic aerosol when oxidized by OH or ozone;
calculated organic mass yields for the experiments conducted are similar for
ozonolysis (15% and 5% respectively) and photooxidation (23% and
8% respectively). The non-salt organic aerosol formed appears to be more
stable than the nitrate salts and does not quickly repartition back to the
gas phase. |
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