World Meteorological Organization Global Ozone Research and Monitoring Project
Quick post. But I didn't see the answer there.
I'm working from memory again (getting worse all the time), but the Civil Defense manuals written from the old International Geophysical Year data, had always stated that air from the northern hemisphere wouldn't easily cross into the southern hemisphere. That's why all the science fiction writers would go to Australia after their nuclear wars.
Since almost all the CFC's come from the northern hemisphere, there would have to be a whopper of a mechanism to preserve CFC's all the way to the south pole when almost none get to north pole.