Pioneers In Ozone Research Win Nobel Prize

Three fellows of the American Geophysical Union were awarded the Nobel prize in the

area of atmospheric research by the Royal Swedish Academy of Sciences in 1995. The

honored professors were: Paul Crutzen of the Max-Plank Institute for Chemistry in Mainz,

Germany; Mario Molina of the Massachusetts Institute of Technology, and F. Sherwood

Rowland of the University of California, Irvine. The steps they took to gain an understanding

of the chemistry of the ozone layer (formation and decomposition of ozone) well qualified

them for this honor.

In the past, most researchers thought that ozone depletion was a direct result of

catalytic reactions involving OH and HO2 radicals. Crutzen did not believe in this and,

therefore, chose to demonstrate significance of nitrogen oxides (NO and NO2). Noticing a

correlation between ozone depletion and nitrogen oxide concentration in the upper

atmosphere, he became the first to propose how the nitrogen oxides got to the stratosphere.

The nitrogen oxides react with ozone without being consumed, thus greatly enhancing the

ozone layers rate of reduction.

Molina and Rowland then came into play with their joint hypothesis stating that,

fluorocarbons in general and chlorofluorocarbons (CFC's and freons) in particular, posed a

serious threat to the ozone layer. At the time of their hypothesis, chlorofluorocarbons were

used in refrigerators, air conditioners, plastic foams, and most aerosol sprays. Molina and

Rowland realized that the chemically stable CFC's could be transported to the stratosphere via

normal air movements. There, ultraviolet light would break up the molecules and release

chlorine, a chemical which catalyzes ozone destruction. Because of this finding, the U.S.

banned CFC's as aerosol propellants in 1978. This award is being hailed as a great

recognition for atmospheric science as a whole. May other scientists follow in their footsteps.