How is ozone layer damaged?

Man-made chemicals have damaged the ozone layer that protects the earth from ultra violet (UV) radiation.Aerosols and old refrigerators have released CFCs into the atmosphere. UV radiation breaks down CFCs in the upper stratosphere, releasing chlorine. Once released, chlorine becomes a catalyst of ozone destruction. A catalyst is something that makes a chemical reaction happen more easily, but it remains unchanged or reforms by the end of the reaction. It can then take part in the reaction again.