<P> Since the late 1970s , the use of CFCs has been heavily regulated because of their destructive effects on the ozone layer . After the development of his electron capture detector , James Lovelock was the first to detect the widespread presence of CFCs in the air , finding a mole fraction of 60 ppt of CFC - 11 over Ireland . In a self - funded research expedition ending in 1973 , Lovelock went on to measure CFC - 11 in both the Arctic and Antarctic , finding the presence of the gas in each of 50 air samples collected , and concluding that CFCs are not hazardous to the environment . The experiment did however provide the first useful data on the presence of CFCs in the atmosphere . The damage caused by CFCs was discovered by Sherry Rowland and Mario Molina who , after hearing a lecture on the subject of Lovelock 's work , embarked on research resulting in the first publication suggesting the connection in 1974 . It turns out that one of CFCs ' most attractive features -- their low reactivity -- is key to their most destructive effects . CFCs ' lack of reactivity gives them a lifespan that can exceed 100 years , giving them time to diffuse into the upper stratosphere . Once in the stratosphere , the sun 's ultraviolet radiation is strong enough to cause the homolytic cleavage of the C - Cl bond . </P>
when was the problem of cfc 's discovered
1974