Depletion of the ozone layer. Choloroflourocarbon (CFCS) are dangerous because of their destructive reaction with Ozone particles, which provide the Earth with a protective layer or shield against UV radiation. Depletion of the ozone layer begins when when CFC gets into the stratosphere. Sunlight breaks up cfcs releasing Chlorine Atom. Chlorine atoms in turn react with Ozone, starting a chemical cycle that destroys the ozone layer in that area. Once the ozone layer is depleted, there's nothing holding back the harmful UVB wavelengths of ultraviolet light (UV light) from passing through the Earth's atmosphere causing havoc on plants and animals.
