Tropospheric ozone concentration at the tropopause. About 90% of total ozone in the atmosphere is in the stratosphere, and 10% is in the troposphere. Although tropospheric ozone is less concentrated than stratospheric ozone, it is of concern because of its health effects. Ozone in the troposphere is considered a greenhouse gas, and may contribute to global warming. Photo-chemical and chemical reactions involving ozone drive many of the chemical processes that occur in the troposphere by day and by night. At abnormally high concentrations (the largest source being emissions from combustion of fossil fuels), it is a pollutant, and a constituent of smog.
Views of Lyndon LaRouche and the LaRouche movement Science & Technology", which conducted what has been called "a very effective campaign of misinformation on the issue of ozone depletion", published "The Holes in the Ozone Scare" in 1992. The book, by LaRouche followers Rogelio Maduro and Ralf Schauerhammer, said that chlorofluorocarbons (CFCs) were not destroying the ozone layer and opposed the proposal to ban them. It asserted that most chlorine in the atmosphere came from oceans, volcanoes, or other natural sources, and that CFCs were too heavy to reach the ozone layer. It went on to say that even if the ozone layer were depleted there would not