Refrigerants

• The most common emitter of CFCs are refrigerants, particularly those used after the 1930s. Dupont brand named their new product "Freon," but the CFC-based refrigerant was produced worldwide under a variety of brand names. When old refrigerators, cars, air conditioners and other machines with this coolant are not properly disposed of, they leak CFCs into the atmosphere as liquids evaporate or work their way into the soil.
  
  

Aircraft Halon

• Aviation regulations in some countries still require fire suppression systems outfitted with Halon, a coolant containing CFCs. As of 2011, a safe and effective alternative has not been found. Despite using the dangerous chemical, the industry must follow certain safety measures to dispose of the refrigerant responsibly and to recycle the material when possible.
  
  

Aerosols

• Gasses containing CFCs were used for a long time as components in aerosol cans and propellant liquids. They were phased out of aerosol production in 1999 in favor of less harmful hydrocarbon alternatives. However, since CFC molecules have a lifetime of 20 to 100 years in the stratosphere, the damage done in previous decades continues to make an impact.
  
  

Rogue CFCs

• As refrigerants and aerosol cans containing CFCs become older and more obsolete, people tend to forget about them, leaving them eventually to leak and further contaminate the atmosphere. E! Science News reports that researchers at the University of East Anglia are working on methods to pinpoint local sources of CFC exposure, such as old CFC refrigerators. Their research involves collecting air from the stratosphere and using mass spectrometers to determine the chemical makeup of CFC contamination.