Ozone-depletion scientist dies
Frank Sherwood Rowland, who discovered that CFCs that were once used in refrigeration and air-conditioning systems contributed to the thinning of the ozone layer, particularly above Antarctica, died last month. He was formerly professor of Chemistry and the University of California. The use of these substances was banned by the Montreal Protocol from 1 January 1989. The one remaining refrigerant with any ozone-depletion potential, HCFC 22 (ODP 0.05) is also well on its way to being phased out.
The key element of his work relating to the ozone layer was to suggest that CFCs are decomposed by solar radiation in the stratosphere, releasing chlorine monoxide and atoms of chlorine that can individually destroy large numbers of ozone molecules before eventually decomposing.
The results of his research were first published in Nature in 1974 and stimulated further scientific investigation. The US National Academy of Science agreed with the findings, leading to the banning of CFCs in aerosols in the USA from 1978.
Frank Sherwood Rowland was prompted into his investigation by the discovery by British Scientist James Lovelock of the widespread presence of CFCs in the atmosphere. He also measured the concentration of CFC 11, a popular refrigerant, in the atmosphere but did not realise the threat to the ozone layer. However, his data was used by Sherwood Rowland to put forward the theory that damage was being caused.