Final answer:
CFCs remain in the atmosphere for up to 100 years, contributing to ozone depletion. The Montreal Protocol has successfully initiated the phaseout of CFCs, helping in the recovery of the ozone layer.
Step-by-step explanation:
CFCs, or chlorofluorocarbons, once widely used in products such as refrigerants, air conditioning systems, foams, and aerosols, are known to contribute to ozone depletion. These chemicals can remain in the atmosphere for a very long time. Answering the student's question, CFCs remain in the atmosphere for up to 100 years. This longevity, combined with their ability to destroy ozone molecules, poses a significant risk to the ozone layer.
Due to the Montreal Protocol agreement in 1987, international efforts have successfully started to phase out the production and use of CFCs, showing signs of recovery in the ozone layer, despite some variability and occasional enlargements in the ozone hole.