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| Titel |
Modeling of gaseous methylamines in the global atmosphere: impacts of oxidation and aerosol uptake |
| VerfasserIn |
F. Yu, G. Luo |
| 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 ; 14, no. 22 ; Nr. 14, no. 22 (2014-11-27), S.12455-12464 |
| Datensatznummer |
250119190
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| Publikation (Nr.) |
 copernicus.org/acp-14-12455-2014.pdf |
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| Zusammenfassung |
| Gaseous amines have attracted increasing attention due to
their potential role in enhancing particle nucleation and growth and
affecting secondary organic aerosol formation. Here we study with a
chemistry transport model the global distributions of the most common and
abundant amines in the air: monomethylamine (MMA), dimethylamine (DMA), and
trimethylamine (TMA). We show that gas phase oxidation and aerosol uptakes
are dominant sinks for these methylamines. The oxidation alone (i.e., no
aerosol uptake) leads to methylamine lifetimes of 5–10 h in most parts
of low and middle latitude regions. The uptake by secondary species with
uptake coefficient (γ) of 0.03 (corresponding to the uptake by
sulfuric acid particles) reduces the lifetime by ~30% over
oceans and much more over the major continents, resulting in a methylamine
lifetime of less than 1–2 h over central Europe, eastern Asia, and eastern
US. With the estimated global emission flux, from the literature, our
simulations indicate that [DMA] in the model surface layer over major
continents is generally in the range of 0.1–2 ppt (parts per trillion) when γ = 0.03
and 0.2–10 ppt when γ = 0, and decreases quickly with altitude.
[DMA] over oceans is below 0.05 ppt and over polar regions it is below 0.01 ppt.
The simulated [MMA] is about a factor of ~2.5 higher
while [TMA] is a factor of ~8 higher than [DMA]. The modeled
concentrations of methylamines are substantially lower than the limited
observed values available, with normalized mean bias ranging from −57
(γ = 0) to −88% (γ = 0.03) for MMA and TMA, and
from −78 (γ = 0) to −93% (γ = 0.03) for DMA. |
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