How many molecules of ozone can be harmed by one molecule of CFC?

A single CFC molecule can destroy 100,000 ozone molecules.

How long will it take for the ozone layer to recover?

Almost 30 years after the Montreal Protocol was signed, the ozone layer is just starting to heal, according to a panel of 300 scientists that reports every four years to the United Nations on the subject. However, it will take until 2050 for the ozone layer in the mid-latitudes to return to relatively healthy 1980s conditions, the U.N. report said.