The ozone layer is depleted by free-radical catalysts, which break reactive O3 (ozone) back into the benign O2 we eagerly breathe. Chlorofluorocarbons (CFCs) are a class of such catalysts, as is nitrous oxide. CFCs contain only carbon, chlorine, and fluorine in various configurations. CFCs are potent greenhouse gases.
From the late 19th century into the early 1980s, CFCs were used extensively in aerosols and as refrigerants. CFCs were adopted for many industrial processes because they seemed inert: they did not burn, did not react with other substances, nor were they particularly poisonous. Environmentally, the relative stability of CFCs is a substantial hazard: their slow breakdown in the atmosphere produces chlorine free radicals which decimate the ozonosphere.
The lingering presence of CFCs in the atmosphere and their power to extinguish ozone was belatedly discovered in the mid-1970s. They were then quickly regulated, though some CFCs remain in use, as chemists have yet been able to concoct acceptable substitutes. That we refuse to inconvenience ourselves to save ourselves is exemplary of the collective folly which ensures self-extinction.
Because CFCs remain in the stratosphere for up to 100 years, they will deplete ozone long after industrial production of the chemicals ceases. ~ American environmental scientist Bruce Johansen