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Details van artikel 14 van 21 gevonden artikelen
| Titel: |
Ozone decomposition on Saharan dust: an experimental investigation |
| Auteur: |
F. Hanisch J. N. Crowley |
| Verschenen in: |
Atmospheric chemistry and physics |
| Paginering: | Jaargang 3 (2003) nr. 1 pagina's 119-130 |
| Jaar: |
2003 |
| Inhoud: |
The heterogeneous reaction between O<sub>3</sub> and authentic Saharan dust surfaces was investigated in a Knudsen reactor at approx 296 K. O<sub>3</sub> was destroyed on the dust surface and O<sub>2</sub> was formed with conversion efficiencies of 1.0 and 1.3 molecules O<sub>2</sub> per O<sub>3</sub> molecule destroyed for unheated and heated samples, respectively. No O<sub>3</sub> desorbed from exposed dust samples, showing that the uptake was irreversible. The uptake coefficients for the irreversible destruction of O<sub>3</sub> on (unheated) Saharan dust surfaces depended on the O<sub>3</sub> concentration and varied between 3.5 x 10<sup>-4 </sup> and 5.5 x 10<sup>-6</sup> for the initial uptake coefficient (<font face='Symbol'>g</font><sub>0</sub> approx 3 x 10<sup>-5</sup> at 30 ppbv O<sub>3</sub> STP) and between 4.8 x 10<sup>-5</sup> and 2.2 x 10<sup>-6</sup> for the steady-state uptake coefficient (<font face='Symbol'>g</font><sub>ss</sub> approx 7 x10<sup>-6</sup> at 30 ppbv O<sub>3</sub> STP). At very high O<sub>3</sub> concentrations the surface was deactivated, and O<sub>3</sub> uptake ceased after a certain exposure period. Sample re-activation (i.e. de-passivation) was found to occur over periods of hours, after exposure to O<sub>3</sub> had ceased, suggesting that re-activation processes play a role both in the laboratory and in the atmosphere. |
| Uitgever: |
Copernicus GmbH (provided by DOAJ) |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 14 van 21 gevonden artikelen
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