Final answer:
Water purification systems do not source chlorofluorocarbons (CFCs). CFCs, which damage the ozone layer, are mainly used in refrigeration, air conditioning, and as solvents. The correct source not associated with CFCs is a) water purification systems.
Step-by-step explanation:
Chlorofluorocarbons (CFCs) are man-made chemical compounds that have been used in a variety of applications, including as refrigerants, propellants, and solvents. The sources of CFCs include refrigeration systems, air conditioning systems, and industrial solvents. On the other hand, water purification systems do not release CFCs. Therefore, the correct answer to which of these is not a source of chlorofluorocarbons is a) water purification systems.
CFCs have a significant environmental impact as they deplete the ozone layer. Due to their long lifetime in the atmosphere and the harm they cause, CFCs have been phased out under the Montreal Protocol and replaced with hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs). However, both CFCs and substitutes such as HCFCs and HFCs have their environmental consequences. In summary, CFCs have historically been used extensively in refrigeration systems, air conditioning systems, and as industrial solvents.