Ozone is a colorless gas with a pungent, irritating odor.
It is a natural part of the environment where it is found both in the upper atmosphere and at ground level. In addition, man's activities create emissions which contribute substantially to ozone formation at ground level. In the upper atmosphere, the problem is too little ozone. CFC's are used as the coolant in air conditioners and refrigerators and have also been used in hair and deodorant sprays. In the United States and many other countries, CFC's are being phased out.