Final answer:
CFCs contribute to the depletion of ozone in the stratosphere. Ultraviolet light causes CFCs to decompose, producing atomic chlorine, which interacts with ozone molecules. The decrease in atmospheric concentrations of atomic chlorine has led to a reduction in the size of the ozone hole.
Step-by-step explanation:
The actual measurements of CFCs in air samples from the stratosphere are not explicitly stated in the given information. However, it is mentioned that CFCs contribute to the depletion of ozone in the stratosphere. Ultraviolet light causes CFCs to decompose, producing atomic chlorine, which then reacts with ozone molecules, resulting in a net removal of ozone from the stratosphere. The worldwide effort to reduce the use of CFCs has led to a decrease in atmospheric concentrations of atomic chlorine and a decrease in the size of the ozone hole.