Reduction of the concentration of ozone in the ozone layer as a result of the action of atmospheric pollutants. The thinning of the ozone layer and the appearance of a visible "hole" over the South Pole region has been the subject of extensive public policy discussions, media coverage, and national legislation and international treaties. Stratospheric ozone shields living organisms on Earth from the harmful effects of the Sun's ultraviolet radiation; even a relatively small decrease in the stratospheric ozone concentration can result in an increased incidence of skin cancer in humans and in genetic damage in many organisms. The prohibition of the manufacture or use of chlorofluorocarbons in the United States, and many other nations, is perhaps the most visible positive result to date of this debate.
