March 19

Mario Molina, Protector of the Ozone Layer

On this day in 1943, Mario Molina, an MIT professor who won the Nobel Prize in Chemistry, was born in Mexico City, Mexico. Molina, F. Sherwood Rowland, and Paul Crutzen received the Nobel Prize in 1995 for their research on the ozone layer. They discovered that certain chemicals used in common items such as spray cans and air conditioners destroy the ozone in the atmosphere.

The ozone layer protects the Earth from the sun's dangerous ultraviolet rays. Molina found that chlorofluorocarbon chemicals (CFCs), used in spray cans and in refrigerators, break down the ozone when they are released into the air. This finding led to an international environmental treaty, which bans the production of industrial chemicals that deplete the ozone layer.