Role of chlorofluorocarbons in stratosphere ozone depletion

In the 1980s about 1 million tons of CFCs were released annually into the atmosphere. These compounds are nontoxic, nonflammable, nonreactive, and have useful condensation properties (suiting them for use as coolants, for example) on account of these favorable characteristics they found a multitude of applications. There were several CFCs of commercial importance, like CFC-11, CFC-12. The code numbers for CFC compounds are shown in Box 2. 

Until recently CFC-12 was used extensively in automobile air conditioners, from which much was released (aboutO.5 kg per vehicle annually) to the atmosphere during use and servicing. Today special equipment is used to capture the CFCs (and their modern replacements) when air conditioners in cars are serviced. 

CFC-12 has been widely used also for producing rigid plastic foams. The characteristic example is the formation of foam sheets such as those used in white trays of the sort to package fresh meat products and in hamburger clamshell cartons used by fast-food restaurants. 

Both CFC-11 and CFC-12 were employed extensively as propellants in aerosol spray cans. This application has greatly decreased in some developed countries (USA, Canada, Norway, and Sweden) but still utilization of CFCs in spray cans continues elsewhere, especially in Asia. 

The other CFC of major environmental concern was CFC-113, C2F3CI3. It was used extensively for cleaning the glue, grease and solder residues from electronic circuit boards after their fabrication, up to 2 kg m . 

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