Chlorofluorocarbons (CFCs) are a group of chemical compounds that has been shown to have caused the ozone holes in the stratosphere over both the North and South poles. A seasonal hole appears above Antarctica in September.

These holes in the atmosphere allow the sun’s rays to enter the earth without a protective layer to shield us, which may cause an increase in skin cancer.

CFCs are an aggregation of chemical compounds that include alkanes and haloalkanes. These chemicals are used in aerosol spray cans, refrigerants, foam blowing (to make packing foam and foam cups), fire extinguishers and solvents to clean electronic equipment.

The use of CFCs began in the 1920, when carbon tetrachloride was used in fire extinguishers, until the end of World War II. In 1928, Thomas Midgley developed CFCs as a replacement for a mixture of ammonia, chloromethane and sulfur dioxide that was commonly used as a refrigerant.

The CFC was superior to the former compounds because it was non-toxic, had a low boiling point and was generally non-reactive.

CFCs continued to be used, mostly by the military and in firefighting, until 1974 after the journal, ¬Nature by Molina and Rowland, showed their findings regarding the ozone layer depletion. They won the Nobel Prize in Chemistry for that work.

They found that by adding hydrogen and creating hydrochlorofluorocarbons (HCFC), made the compound less stable in the lower stmosphere, which meant they would break down before they reached the ozone layer. Eventaully, the chlorine would be taken out, creating HFC with an even less stable compound.

Scientists show that the decreases in CFCs have been helping the ozone layer, particularly over Antarctica, and predict that that particular hole will close permanently by the year 2050.

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