From ten to forty miles above the earth's surface is the stratosphere. The stratosphere contains the protective ozone layer that surrounds the earth. Ozone is a form of oxygen which in the stratosphere blocks the sun's harmful rays form reaching earth.
Without this ozone layer in the stratosphere, too many harmful rays can reach the earth's surface, causing skin cancer in humans and damage to plant tissue.
In 1988 National Aeronautics and Space Administration (NASA) conducted a study which showed the ozone layer had been depleted by 3 percent over the past twenty years. Halons used in increasingly high technological fire fighter equipment, chlorofluorocarbons (CFC's) group of compounds used as propellants for aerosol spray, plastic packaging, foam insulation, cleaning fluids, air conditioning and refrigeration are contributing factors to depletion.
These halons and CFCs, once released into the air rise slowly into the atmosphere, where they and methyl chloroform, an industrial solvent, are broken up by the sun's ultraviolet rays, releasing chlorine (Cl) and bromine (Br) atoms. The chlorine atoms from CFC's and bromine from halons disrupt the ozone molecules, breaking them up into molecular oxygen. Molecular oxygen depletes the ozone layer.
Every one percent loss of the ozone layer increases the potential for skin cancer by five to seven percent. The increase radiation from the sun also burn tissues of animals and plants, as well as causing eye problems for humans and other animals. The most dangerous might be changes to the human immune system. The increased ultraviolet radiation affected the food chain, by killing plankton. Plankton is the base of the food chain. The greatest ozone loss is at the Antarctica where sometimes it measures a fifty percent decrease, usually in the winter and early spring. If it happens there it can happen anywhere on earth.