CFCs and other ozone-depleting substances (ODS) stay for a very long time (10-20 yrs) while ascending to the stratosphere
In the stratosphere, they break down under UV radiation into highly reactive atoms of chlorine (Cl), fluorine (F) and Bromine (Br)
These atoms then react with and break ozone (O3) down into oxygen (O2) and atoms of oxygen (O)
Each Cl in CFC can convert hundreds of O3 into O2