Explain why the photolysis of chlorine during polar sunrise did not lead to an Antarctic ozone hole back then prior to the 1930?

The rate constants for the reactions of atomic chlorine and hydroxyl radical with ozone are given by 3 x 10-11e-250/T and 2 x 10-12 e-940/T where T is the temperature in Kelvin. Calculate the ratio of rate of ozone destruction by atomic chlorine to the rate of ozone destruction by hydroxyl radical in the Antarctic ozone hole, in which the temperature is -80 oC and the concentrations of atomic chlorine and hydroxyl radical are equal. Assume that the reaction of ozone with the X. species ( either atomic chlorine and hydroxyl radical) is rate determining.

Chlorine monoxide accumulates in the stratosphere above Antarctica each winter and plays a key role in the formation of the ozone hole above the South Pole each spring. Eventually, ClO decomposes according to the equation: 2ClO(g) --> Cl2​(g)+O2​(g) The second-order rate constant for the decomposition of ClO is 7.33×109 M–1s–1 at a particular temperature. Determine the half-life of ClO when its initial concentration is 1.11×10-8 M .