Nobel Prize-winning American scientist F. Sherwood Rowland, whose work demonstrated the role of human activity in the thinning of the Earth's protective ozone layer, has died at the age of 84.
The university where he conducted his research, the University of California at Irvine, in southern California, said Rowland passed away of complications from Parkinson's disease.
Rowland was among three scientists awarded the 1995 Nobel Prize for chemistry for explaining how the ozone layer is depleted through chemical processes in the atmosphere, including by human use of chlorofluorocarbons (CFC).
The depletion of the ozone layer results in a reduction of Earth's protection from ultraviolet radiation. The work of Rowland and his associates showed how manmade compounds can combine with solar radiation to destroy ozone molecules.
In early 1970s, when the scientists published their findings, CFCs were used in many household products, from hair spray cans to refrigeration units. The scientists predicted that if human use of CFCs were to continue at an unchanged rate, the ozone layer would be depleted within several decades.
The scientists' work faced strong opposition from U.S. chemical manufacturers, who viewed the research as a threat to the billion-dollar chemicals industry.
The leading CFC maker, DuPont, took out full-page newspaper advertisements indirectly questioning Rowland's credibility and calling the CFC problem a hypothesis.
"Aerosol Age" magazine even said Rowland must be a Soviet KGB agent to promote such a wild idea.
The nontoxic properties of CFCs were at one time thought to be environmentally safe.
The findings of Rowland and the other researchers, however, were confirmed by other scientists. And their work gained widespread recognition with the later discovery of the ozone hole over the Earth's polar regions.
Manufacturers began to phase out CFCs in the late 1980s and the Montreal Protocol, an international agreement to phase out CFC products, was signed by the United States and other nations in 1987.
'Integrity And Grace'
In a written statement, Kennth Janda, the dean of UC Irvine's physical sciences department, said Rowland's work had "saved the world from a major catastrophe" that could have been caused by uncontrolled CFCs.
The statement added that Rowland had pursued his research with "integrity and grace" and an unwavering "commitment to science, truth, and humanity."
His work is also seen as adding key momentum to the global environmental movement and the subsequent work by scientists to understand the consquences of the manmade emissions thought to contribute to global warming.
Rowland's research earned him many prizes. He is seen as having an influence on a generation of climate-change scientists.
With AP and U.S. media reports