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Sherwood Rowland and Mario Molina

About the contributions Sherwood Rowland and Mario Molina made to environmental science

Emily Redfield

on 17 September 2012

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Transcript of Sherwood Rowland and Mario Molina

photo credit Nasa / Goddard Space Flight Center / Reto Stöckli Sherwood Rowland and Mario Molina CFCs (chlorine, fluorine, and carbon atoms) were developed in 1930s and called freon. CFCs were used in refrigerators, Styrofoam, and aerosols. Since CFCs are nontoxic, nonflammable, and don't react with any common chemicals, they were assumed to be safe for the environment James Lovelock made a device that could detect CFCs in the air and found that it was present in large amounts on hazy days, clear days, and all around the world. In 1972 he presented his findings, this got the attention of Sherwood Rowland Rowland wanted to know what would happen to CFCs once they reached the upper atmosphere. He was joined by the newest member of his research group, Mario Molina. Although, unlike many chemicals which breakdown in the lower atmosphere, no known chemical processes seemed to be able to affect CFCs in the lower atmospher, Molina knew that once any molecule got high enough solar radiation would break it apart. Molina found out that the cchlorine that would be released from CFC in the upper atmosphere would react catalytically with ozone, and a single chlorine atom could destroy around 100,000 ozone molecules A depleted ozone layer would likely mean higher rates of skin cancer, cataracts, and immune system problems, in addition more UV radiation could harm plants and marine ecosystems. In 1995 Rowland and Molina won the Nobel Prize for chemistry for discovering damage to the ozone caused by spray cans and cooling agents This led to an international treaty banning the production of industrial chemicals that reduce the ozone layer. Researcher Joseph Farman had been collecting atmospheric data at Halley Bay, Antarctica since 1957. In 1982 he noticed a 40% drop in ozone levels and thought it was an equipment failure, but after getting new equipments the next year the decrease was still there. He reanalyzed his data and found that ozone had been dropping since 1977. The discovery of this ozone hole validated Rowland and Molina's hypothesis •http://tech.mit.edu/V115/N48/nobel.48n.html
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