CF₃ chemistry: Potential implications for stratospheric ozone

Abstract

Previous evaluations of the impact of fluorine chemistry on stratospheric ozone have concluded that the role of fluorine compounds in catalytic ozone removal is negligible. However, recent investigations of the degradation pathways for compounds containing CF 3 groups indicates that if the reaction of CF 3 O with O 3 is sufficiently fast, there may be an ozone impact. Some recent measurements indicate that the reaction rate constant of CF 3 O+O 3 is sufficiently low that the ozone impact is likely to be small. However, it is not possible a‐priori to rule out significant ozone removal without additional kinetic data on other reactions. We present calculations to illustrate how different key reactions affect the calculated stratospheric concentrations of the CF 3 X species (CF 3 , CF 3 O, CF 3 O 2 , CF 3 OH, CF 3 OOH, CF 3 ONO 2 , CF 3 O 2 NO 2 , CF 3 OOCl) and their ability to remove stratospheric ozone. We utilize our results to suggest kinetic measurements that could substantially reduce the uncertainties in CF 3 chemistry relevant to the determination of ozone depletion potential of CF 3 ‐bearing compounds.