What are the most widely used ozone-depleting halocarbons?
CFCs are widely used as coolants in refrigeration and air conditioners, as solvents in degreasers and cleaners, and as a blowing agent in the production of foam. Emissions of CFCs account for roughly 80 percent of total stratospheric depletion. HCFCs (Hydrochlorofluorocarbons) contain chlorine but, unlike CFCs, they also contain hydrogen (the H) which causes them to break down in the lower atmosphere. They are called transition chemicals because they are considered an interim step between strong ozone-depleters and replacement chemicals that are entirely ozone-friendly. Carbon tetrachloride is used as an industrial solvent, an agricultural fumigant, and in many other industrial processes including petrochemical refining. It accounts for less than 8 per cent of total ozone depletion. Methyl chloroform is a versatile, all-purpose industrial solvent used primarily to clean metal and electronic parts. Methyl chloroform accounts for roughly 5 per cent of total ozone depletion. Halons are us
