The objectives are to identify uncertainties regarding the potential environmental effects of the proposed substitutes of the current used CFCs, eg, hydrochlorofluorocarbons and hydrofluorocarbons.
The data obtained in this project have greatly contributed to demonstrate that the secondary degradation products of the halocarbons, especially the HCFCs, have a negligible effect on stratospheric ozone. The rate constant data provided for the primary reaction with OH have been used to determine the lifetimes of the halocarbons, which are key parameters in the calculation of the ozone depletion potential and greenhouse warming potential for these compounds.
The project is concerned with the kinetics and mechanisms of oxidation of chlorine and bromine containing compounds under atmospheric conditions. For an accurate assessment of the ozone depletion potential the degradative oxidation mechanisms of several alternative CFCs products will be investigated, with particular emphasis on the determination of tropospheric sinks for their degradation intermediates.
The rate constants will be determined for a number of these intermediates.
The following processes will be investigated:
reactions of hydroxylradicals with halogenated alkanes and aldehydes;
absorption cross sections and photolysis for halogenated carbonyl compounds;
mechanisms for the oxidation of halogenated alkanes.
Funding SchemeCSC - Cost-sharing contracts
OX11 0RA Didcot - Oxfordshire