The ozone layer is responsible for protecting the earth from UV rays and people from skin cancer, cataracts and for keeping our immune system active. Some gases destroy the molecules of O3 (ozone) in the atmosphere, among them are the chemical pesticides used in agriculture, the use of organic fertilizer helps to reduce these pesticides that damage the atmosphere.
Gases containing chlorine and bromine destroy ozone. The air carries these materials to the stratosphere where only one of these atoms can destroy several thousand ozone molecules before they go back down into the atmosphere and are removed by rain or snow. Bromine is found in methyl bromide, commonly used in chemical pesticides.