CFC

CFC most commonly refers to chlorofluorocarbons, a class of synthetic organic compounds composed of carbon, chlorine, fluorine, and sometimes hydrogen. They are typically colorless, nonflammable, and chemically stable at room temperature, with long atmospheric lifetimes. This stability made them useful in a variety of applications, including refrigerants for air conditioners and refrigerators, solvents for electronics and precision cleaning, propellants for aerosol products, and blowing agents for rigid foam insulation.

Historically, CFCs were developed in the early to mid-20th century and rapidly adopted for these purposes due to their effective performance and safety compared with earlier substances. Common examples include CFC-11 and CFC-12. However, their stability allows them to persist in the atmosphere and, when they reach the stratosphere, UV radiation can release chlorine atoms from the molecules.

Chlorine atoms catalytically destroy ozone in the stratosphere, initiating cycles that convert ozone (O3) into ordinary oxygen (O2) and reduce the ozone layer that protects living organisms from ultraviolet radiation. This ozone-depletion potential led to widespread environmental concern and international action starting in the 1980s.

Regulatory action culminated in the Montreal Protocol of 1987 and subsequent amendments, which phased out production and consumption of most CFCs and established schedules for replacement with less harmful substances. While many CFCs have been largely phased out, replacements such as HCFCs and HFCs were later used, though these also pose environmental trade-offs: HCFCs are less ozone-depleting but still problematic; HFCs do not deplete ozone but contribute to greenhouse warming. Today, CFCs remain largely in older equipment and in limited, controlled production for regulated uses, with ongoing efforts to manage substitutes and curb emissions.