Ozone decomposition on Saharan dust: an experimental investigation
Item
Title (Dublin Core)
Ozone decomposition on Saharan dust: an experimental investigation
Description (Dublin Core)
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.
Creator (Dublin Core)
Hanisch, F.
Crowley, J. N.
Date (Dublin Core)
2018-06-29
Type (Dublin Core)
Text
Format (Dublin Core)
application/pdf
Identifier (Dublin Core)
10.5194/acp-3-119-2003
https://acp.copernicus.org/articles/3/119/2003/
Source (Dublin Core)
eISSN: 1680-7324
Language (Dublin Core)
eng
