CFCs And Alternative Aerosol Propellents

In 1928, an industrial organic scientist by the name of Thomas Midgley was working at a research lab at General Motors. There he discovered “two inert, nontoxic, nonflammable gasses with excellent refrigerant properties” (Fisher). These two gasses were dichlorodifluoromethane and trichloromonofluoromethane, which are both simple variations of methane. Methane has the formula CH4, where there are four hydrogen molecules for each carbon molecule. In dichlorodifluoromethane, chlorine and fluorine replace the hydrogen to have the formula CCl2F2. In trichloromonofluoromethane, the four hydrogen are kicked out and replaced with three chlorines and only one fluorine. Combined together they create chlorof

In 1970, Jim Lovelock, a “respected researcher holding a PhD” had quit his job because of the stability it offered. He believed that the stability would inhibit his creativity and restrict him from enjoying science. He ended up setting up a small lab in his country home in Bowerchalke and did consulting research. One day, in 1970, Lovelock got an idea to measure CFC’s in the atmosphere. Since the CFCs could not be broken down by water (or by any other substance for that matter) Lovelock calculated all the cans that had been sold and how many refrigerators had been thrown away in the world and concluded that there would be a trace amount of the gas in the atmosphere. Lovelock wanted to measure the amount of CFCs in the atmosphere just because he could. He had invented a new device that was capable of measuring trace amounts of gasses and wanted to try it out. He also figured that since CFCs had been around for about 15 years, they would be excellent tracers for studying atmospheric circulation.

Since CFCs can no longer be used as propellants in aerosol cans, the industry had to discover other gasses that could do the job and still be friendly to the environment. There are several common types that can be classified into three groups.

In 1973 Mario J. Molina, who had just received his PhD, was looking for a subject to study for his postdoctoral. The professor who he was supposed to work with, F. Sherry Rowland, was on his way to a six-month vacation and suggested to Molina to find out what happens to CFCs. The readings from Lovelock showed that the amount of CFCs in the atmosphere almost equaled the amount of CFC produced up until that time. That proved the theory that the gas was totally un-reactive and once they floated up in the air, they stayed there. Rowland gave Molina the task of finding out how the CFCs decomposed. He pointed out that nothing could last forever so something must happen to the CFCs.

Some topics in this essay:
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