Role of photochemical reactions and photoreactants for the depletion of ozone in atmospheric waters
- Swiss Federal Institute for Environmental Science and Technology, Dubendorf (Switzerland)
In the day-time troposphere atmospheric droplets act as photoreactors and possibly are sinks for atmospheric ozone, although the rate constant for direct photolysis of ozone in waters exposed to terrestrial sunlight is very low (<0.0001 s{sup -1}). However, gaseous photoreactants such as HO{sub 2} radicals quickly equilibrate with the liquid phase and some further aqueous HO{sub 2}/O{sub 2}{sup -} is produced when ubiquitous atmospheric iron compounds, such as iron(III) oxalate are photolysed. The steadily transferred ozone reacts with these species to produce OH radicals which, by reactions with dissolved formate and formaldehyde, are transformed into further HO{sub 2}/O{sub 2}{sup -}. A radical-type chain reaction evolves that is inhibited by OH radical scavengers such as acetate. To test and calibrate the kinetics of these ozone depleting chain-reactions these were e.g. initiated by photolysing iron(III) oxalate in water that contained formate or formaldehyde as promoters and acetate as an inhibitor.
- OSTI ID:
- 214652
- Report Number(s):
- CONF-950801--
- Country of Publication:
- United States
- Language:
- English
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