What makes cfc

Commemorative Booklet PDF. In the s, refrigeration and air conditioning systems used compounds such as ammonia, chloromethane, propane and sulfur dioxide as refrigerants. Though effective, the compounds were toxic and flammable, and exposure to them could result in serious injury or death.

A team of chemists at Frigidaire led by Thomas Midgely Jr. The team focused their effort on compounds containing carbon and halogens such as fluorine and chlorine. Such compounds were known to be volatile and chemically inert, both important properties for the team studying their use in refrigeration.

Chlorofluoromethanes are being added to the environment in steadily increasing amounts. These compounds are chemically inert and may remain in the atmosphere for years, and concentrations can be expected to reach 10 to 30 times present levels. Photodissociation of the chlorofluoromethanes in the stratosphere produces significant amounts of chlorine atoms, and leads to the destruction of atmospheric ozone. From an environmental standpoint, ozone is a confusing molecule.

But in the stratosphere, the region of the atmosphere from 6 to 31 miles, ozone absorbs potentially damaging ultraviolet UV radiation. Without a protective ozone layer in the atmosphere, animals and plants could not exist, at least not upon land. Lovelock had measured trichlorofluoromethane CFC in the atmosphere in amounts that suggested that practically all of the CFC ever manufactured was still present in the atmosphere.

Rowland decided to devote a portion of his research to understanding the fate of CFCs in the atmosphere. Although CFCs are inert in the lower troposphere, Rowland realized that they can be broken down by UV radiation once they drift up into the stratosphere.

Each chlorine atom would react immediately with an ozone molecule, setting off a chain reaction that would destroy thousands of ozone molecules. In their paper, they estimated that if CFC use was banned immediately, ozone loss would go on for years. If CFC production continued, however, ozone loss would be even greater. In , the National Academies of Science issued a report affirming the destructive effects of CFCs on stratospheric ozone.

Congressional hearings reached similar conclusions, and states and the federal government began exploring bans on the use of CFCs in aerosol cans. When Rowland lectured on CFCs, industry groups often released statements disputing his claims. Use of HFCs in mobile air conditioning will end with Model Year , while prohibitions on HFC use in new fire suppression systems, cold storage, residential refrigeration, and building chillers go into place on January 1 of , , and , respectively.

In addition to the various production bans, servicers and disposers of appliances and motor vehicle air conditioners are required to obtain technician certification, proper refrigerant recovery or recycling equipment, and keep records. Skip to main content. Air How's the air? Ozone depletion Man-made compounds such as chlorofluorocarbons CFCs , hydrofluorocarbons HCFCs and halons destroy ozone in the upper atmosphere stratosphere.

What Effects do Chlorofluorocarbons Have on Humans? Environmental Problems Caused by Minerals. Landfills Vs. Technological Advancement and the Effect on the Ecosystem. Man-Made Causes of Air Pollution. What Is Industrial Smog? How Tantalum Is Mined. Swanson, J. Butler, B. Hall, S. Cummings, D. Fisher, and A. Raffo, Decrease in the growth rates of atmospheric chlorofluorocarbons 11 and 12, Nature , , , Weiss, B. Miller, J. Huang, F. Alyea, D. Cunnold, P. Fraser, D.

Hartley, and P. Myers, J. Butler, S. Cummings, and J. Butler, J. Elkins, L. Lock, A. Clarke, and A. Suggested Additional Reading: Cagin, S. Scientific Assessment of Ozone Depletion: , edited by D. Albritton, R. Watson, and R. Aucamp, 37 , pp.