Ozone has a molecular weight of 47.998. Pure ozone is a pale blue gas that has a sharp, irritating odor. The word ozone comes from a Greek word meaning to smell. The German chemist Christian Friedrich Schonbein discovered ozone in 1840. Ozone in the upper atmosphere.
Most ozone is found in the upper atmosphere.
This ozone layer in the upper atmosphere shields the earth from 95 to 99 percent of the sun's ultraviolet rays. Overexposure to these rays is a cause of skin cancer. At that time, CFC's were widely used as propellants in aerosol spray cans. Chlorofluorocarbons do not occur in nature. They are industrially produced chemicals.