Final answer:
Ozone depletion is caused by the presence of CFC molecules in the atmosphere. These stable molecules can reach the stratosphere, where they break down and release chlorine atoms that react with ozone molecules. This leads to the destruction of ozone and increased UV radiation at the Earth's surface.
Step-by-step explanation:
Ozone depletion is caused by the presence of CFC (chlorofluorocarbon) molecules in the atmosphere. These CFC molecules are stable and can make their way into the stratosphere, where they can be exposed to high-energy photons. When this happens, the CFC molecules break down and release chlorine atoms. The chlorine atoms can then react with ozone molecules, leading to the destruction of ozone. A single chlorine atom can destroy thousands of ozone molecules. The depletion of ozone results in increased ultraviolet (UV) radiation reaching the Earth's surface.
CFCs are found in refrigerants, air conditioning systems, foams, and aerosols. They are relatively stable and can contribute to ozone depletion for years. However, there is a worldwide effort to reduce the use of CFCs commercially, and the ozone hole is already starting to decrease in size as atmospheric concentrations of atomic chlorine decrease.