Narrator: This is Science Today. Chlorofluorocarbons, or CFCs, which were widely used in products such as aerosol sprays, were banned in 1995. That same year, F. Sherwood Rowland, a professor of chemistry and Earth system science at the University of California , Irvine , shared a Nobel Prize in Chemistry for his part in discovering CFCs were damaging the Earth's protective ozone layer. Rowland explains that CFCs are man-made gases composed of carbon, chlorine and fluorine that were invented in the late 1920s as substitute refrigerants.
Rowland: The early refrigerants were molecules that were easily converted from liquid to gas and the problem that sometimes they escape and they're obnoxious or worse. So, they were looking for an inert material and they specifically designed CFCs as refrigerants. And this ability to convert from a liquid to a gas is also very useful in aerosol propellants. So, the uses grew very rapidly. That's why the CFCs began to accumulate in the atmosphere.
Narrator: For Science Today, I'm Larissa Branin.