The ozone layer is the part of the earth's stratosphere which contains relatively high concentrations of ozone (O3), meaning a few parts per million, much higher than the concentrations in the lower atmosphere, but less than the main components of the atmosphere. The ozone layer was discovered in 1913 by the french physicists Charles Fabry and Henri Buisson.
Various federal laws regulate products which are thought harmful to the ozone layer. After Sweden banned CFC-containing aerosol sprays in 1978, the United States and other developed nations soon passed similar laws. Chlorofluorocarbons continued to be used in other applications, such as refrigeration and industrial cleaning, until after the discovery of the antarctic ozone hole in 1985. After negotiation of an international treaty (the Montreal Protocol), CFC production was sharply restricted beginning in 1987 and phased out completely by 1996.
