Estimates of possible future ozone reductions from continued use of fluoro‐chloro‐methanes (CF2Cl2, CFCl3)

In agreement with arguments put forward by Molina and Rowland (1974) it is concluded that very large reductions in ozone concentrations above about 30 km may result from the continued use of fluoro‐chloro‐methanes (CF 2 Cl 2 and CFCl 3 ), which are dissociated by ultraviolet radiation in the stratosphere and mesosphere, thereby giving rise to ozone‐attacking Cl and ClO. Below about 30 km the reductions in ozone are much smaller and even a slight increase in ozone concentrations may result. The total column abundance of ozone in the atmosphere is, however, reduced by about 10%, assuming that the present rate of production of CF 2 Cl 2 and CFCl 3 remains unaltered.