Purdue, NASA research provides blueprint for molecular basis of global warming, recipe for greener chemistry
Purdue Professor Joseph Francisco says we may have bigger things to worry about than carbon dioxide and the other high-profile greenhouse gases that spill profusely from our car exhausts, coal-fired power plants and the like.
Some lesser-known chemicals are far more effective at trapping heat in the atmosphere which otherwise would bleed harmlessly into space, according to a study by Francisco and NASA colleague Timothy Lee. These compounds, which contain fluorine atoms, are widely used in air conditioning, as a blood substitute, in tracking leaks in natural gas lines, and in the manufacturing of electronics, appliances and carpets, among other things.
Francisco and Lee use computer modeling to understand the complex combinations of atoms and molecules that make the chemicals such potent warming agents and give them, in some cases, lifetimes of thousands of years. The researchers have found that fluorinated compounds are far more efficient at blocking radiation in the “atmospheric window,” the frequency in the infrared region through which radiation from the Earth is released into space, helping to cool the planet. When that radiation is trapped instead of being released, a “greenhouse effect” results, warming the globe. Too many fluorine atoms in too great a concentration appears to change the bonds between atoms in the molecules under study, making them more efficient heat trappers.
An understanding of why the chemicals contribute to global warming on a molecular scale can be applied in developing “greener” alternatives and to testing new chemicals for their global warming capacity before they go to market, Francisco says.