Molina, Mario (1943- )

Mexican-born American chemist

Mario Molina is an important figure in the development of a scientific understanding of the atmosphere. Molina earned national prominence by theorizing, with fellow chemist F. Sherwood Rowland , that chlorofluorocarbons (CFCs) deplete the earth's ozone layer. Molina and Sherwood shared the 1995 Nobel Prize in chemistry, along with the Dutch chemist Paul Crutzen, for their work on the depletion of ozone in the atmosphere. In his years as a researcher at the Jet Propulsion Lab at the California Institute for Technology (CalTech) and a professor at the Massachusetts Institute of Technology (MIT), Molina has continued his investigations into the effects of chemicals on the atmosphere.

Mario José Molina was born in Mexico City to Roberto Molina-Pasquel and Leonor Henriquez. Following his early schooling in Mexico, he graduated from the Universidad Nacional Autónoma de México in 1965 with a degree in chemical engineering. Immediately upon graduation, Molina went to West Germany to continue his studies at the University of Freiburg, acquiring the equivalent of his master's degree in polymerization kinetics in 1967. Molina then returned to Mexico to accept a position as assistant professor in the chemical engineering department at his alma mater, the Universidad Nacional Autónoma de México.

In 1968, Molina left Mexico to further his studies in physical chemistry at the University of California at Berkeley. He received his Ph.D. in 1972 and became a postdoctoral associate that same year. His primary area of postdoctoral work was the chemical laser measurements of vibrational energy distributions during certain chemical reactions. The following year, 1973, was a turning point in Molina's life. In addition to marrying a fellow chemist, Luisa Y. Tan, Molina left Berkeley to continue his postdoctoral work with physical chemist, Professor F. Sherwood Rowland, at the University of California at Irvine.

Both Molina and Rowland shared a common interest in the effects of chemicals on the atmosphere. Both were also well aware that every year millions of tons of industrial pollutants were bilged into the atmosphere. They also had questions about emissions of nitrogen compounds from supersonic aircraft. Molina and Rowland decided to conduct experiments to determine what happens to chemical pollutants that reach both the atmosphere directly above us but also at stratospheric levels, some 10–20 mi (16–32 km) above the earth. Both men knew that within the stratosphere , a thin, diffuse layer of ozone gas encircles the planet, which acts as a filter screening out much of the Sun's most damaging ultraviolet radiation. Without this ozone shield, life could not survive in its present incarnation.

They concentrated their research on the impact of a specific group of chemicals called chlorofluorocarbons, which are widely used in such industrial and consumer products as aerosol spray cans, pressurized containers, etc. They found that when CFCs are subjected to massive ultraviolet radiation they break down into their constituent chemicals: chlorine, fluorine, and carbon . It was the impact of chlorine on ozone that alarmed the two scientists. They found that each chlorine atom could destroy as many as 100,000 ozone molecules before becoming inactive. With the rapid production of CFCs for commercial and industrial use, millions of tons annually, Molina and Rowland were alarmed that the impact of CFCs on the delicate ozone layer within the stratosphere could be life-threatening.

Mario Molina published the results of his and Rowland's research in Nature magazine in 1974. Their findings had startling results. Molina was invited to testify before the United States House of Representative's Subcommittee on Public Health and Environment. Suddenly CFCs were a popular topic of conversation. Manufacturers began searching for alternative propellant gases for their products.

Over the next several years, Molina refined his work and, with Rowland, published additional data on CFCs and the destruction of the ozone layer in such publications as Journal of Physical Chemistry, Geophysical Research Letter, and in a detailed piece entitled "The Ozone Question" in Science. In 1976, Mario Molina was named to the National Science Foundation's Oversight Committee on Fluorocarbon Technology Assessment.

In 1982, Molina became a member of the technical staff at the Jet Propulsion Laboratory at CalTech; two years later he was named senior research scientist, a position he held for an additional five years. In 1989, Mario Molina left the West Coast to accept the dual position of professor of atmospheric chemistry at the MIT's department of Earth, atmosphere and planetary sciences, and professor in the department of chemistry. In 1990, he was one of 10 environmental scientists awarded grants of $150,000 from the Pew Charitable Trusts Scholars Program in Conservation and the Environment. In 1993, he was selected to be the first holder of a chair at MIT established by the Martin Foundation, Inc., "to support research and education activities related to the studies of the environment."

Molina has published more than fifty scientific papers, the majority dealing with his work on the ozone layer and the chemistry of the atmosphere. In 1992, Molina and his wife, Luisa, wrote a monograph entitled "Stratospheric Ozone" published in the book The Science of Global Change: The Impact of Human Activities on the Environment published by the American Chemical Society.

His later work has also focused on the atmosphere-biosphere interface which Molina believes is "critical to understanding global climate change processes." He is the recipient of more than a dozen awards including the 1987 American Chemical Society Esselen Award, the 1988 American Association for the Advancement of Science Newcomb-Cleveland Prize, the 1989 NASA Medal for Exceptional Scientific Advancement, and the 1989 United Nations Environmental Program Global 500 Award.

See also Atmospheric circulation; Atmospheric composition and structure; Atmospheric pollution