Can the ozone layer repair itself?
The concentration of ozone varies throughout the day, presumably because it is generated by the action of ultra-violet light on oxygen molecules. So you could say it "repairs" itself each day during the daylight hours. The long-term average depends mainly on the long-term average intensity of ultra-violet from the Sun, going up and down according to that intensity.
Aerosol chemicals breakdown ozone faster than it builds and that is what scientist think caused the problem in the first place. However recent studies show that not only can the ozone layer repair itself it has already repaired 1%.