What is ODs and CFCs ?
ODS are ozone depleting substances or substances which can react with ozone present in the stratosphere and destroy the same. The most common ODS are chlorofluorocarbons(CFCs), halons like bromochlorodifluoromethan and bromotrifluoromethane, notrogen oxides, carbon tetrachloride, methyl chloroform, methyl bromide, chlorine etc. CFCs or chloroflurocarbons are a group of highly stable, odourless, nontoxic, nonflammable and chemically inert substances made of carbon, fluorine and chlorine. They have been in use as aerosol propellant, refrigerant, blowing agent for producing soft polyurethane forms, fast freezing of foods, industrial sterilisation of medical equipments, metal cleaning and drying etc.. This CFCs are also strong depletors of ozone. According to scientist Molina and Rowl(1974) the stratosphere ozone depletion is due to CFCs because they are man-made stable chemicals which have high residence time of over 100 years, they pass upwardly in the atmosphere and enter there, where t
