chlorofluorocarbon

Chlorofluorocarbons, or CFCs, are a class of synthetic organic compounds that contain carbon, chlorine, and fluorine, often with no hydrogen. They are typically manufactured as colorless, nonflammable liquids or gases. Because of their stability and low reactivity at ground level, CFCs persist in the atmosphere for many years and are transported globally.

Historically, CFCs were widely used as refrigerants, solvents for cleaning precision parts, and propellants in aerosol products and foam-blowing agents. Common examples included refrigerants used in air conditioning and commercial refrigeration, as well as cleaning solvents for electronics.

In the upper atmosphere, ultraviolet radiation breaks down CFC molecules, releasing chlorine atoms that catalytically destroy ozone molecules. This ozone depletion is long-lasting because CFCs have lifetimes of several decades, contributing to the seasonal ozone hole over Antarctica and increased surface UV radiation. The environmental impact is both ozone layer loss and indirect climate effects, although CFCs are not as strong greenhouse gases as some other halogenated compounds.

Policy and phaseout: The recognition of ozone depletion led to international measures such as the Montreal Protocol of 1987 and its subsequent amendments, which progressively banned production and use of CFCs and promoted safer alternatives. By the early 21st century, most developed countries had ceased new CFC production, with some essential-use exemptions and ongoing management of existing stocks in older equipment. Alternatives include HCFCs (less ozone-depleting but still reactive), HFCs, and non-ozone-depleting solvents and refrigerants such as hydrofluoroolefins and hydrocarbons.