 |
| Titel |
Observational constraints on the global atmospheric budget of ethanol |
| VerfasserIn |
V. Naik, A. M. Fiore, L. W. Horowitz, H. B. Singh, C. Wiedinmyer, A. Guenther, J. A. Gouw, D. B. Millet, P. D. Goldan, W. C. Kuster, A. Goldstein |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 10, no. 12 ; Nr. 10, no. 12 (2010-06-17), S.5361-5370 |
| Datensatznummer |
250008558
|
| Publikation (Nr.) |
 copernicus.org/acp-10-5361-2010.pdf |
|
|
|
|
|
| Zusammenfassung |
| Energy security and climate change concerns have led to the promotion of
biomass-derived ethanol, an oxygenated volatile organic compound (OVOC), as
a substitute for fossil fuels. Although ethanol is ubiquitous in the
troposphere, our knowledge of its current atmospheric budget and
distribution is limited. Here, for the first time we use a global chemical
transport model in conjunction with atmospheric observations to place
constraints on the ethanol budget, noting that additional measurements of
ethanol (and its precursors) are still needed to enhance confidence in our
estimated budget. Global sources of ethanol in the model include
5.0 Tg yr−1 from industrial sources and biofuels, 9.2 Tg yr−1 from
terrestrial plants, ~0.5 Tg yr−1 from biomass burning, and
0.05 Tg yr−1 from atmospheric reactions of the ethyl peroxy radical
(C2H5O2) with itself and with the methyl peroxy radical
(CH3O2). The resulting atmospheric lifetime of ethanol in the
model is 2.8 days. Gas-phase oxidation by the hydroxyl radical (OH) is the
primary global sink of ethanol in the model (65%), followed by dry
deposition (25%), and wet deposition (10%). Over continental areas,
ethanol concentrations predominantly reflect direct anthropogenic and
biogenic emission sources. Uncertainty in the biogenic ethanol emissions,
estimated at a factor of three, may contribute to the 50% model
underestimate of observations in the North American boundary layer. Current
levels of ethanol measured in remote regions are an order of magnitude
larger than those in the model, suggesting a major gap in understanding.
Stronger constraints on the budget and distribution of ethanol and OVOCs are
a critical step towards assessing the impacts of increasing the use of
ethanol as a fuel. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|