Which gas is primarily responsible for ozone layer depletion?

Chlorofluorocarbons, commonly known as CFCs, are primarily responsible for the depletion of the ozone layer. This is because CFCs are stable compounds that can persist in the atmosphere for years. When they reach the stratosphere, they are broken down by ultraviolet (UV) radiation, releasing chlorine atoms. These chlorine atoms are highly reactive and can destroy ozone molecules efficiently, breaking them apart and leading to a significant reduction in ozone concentration.

The ozone layer is crucial for protecting the Earth from harmful UV radiation, which can lead to increased rates of skin cancer, cataracts, and other health issues, as well as negative effects on ecosystems. The awareness of CFCs’ role in ozone depletion led to international regulations such as the Montreal Protocol, which aimed to phase out the production and use of substances that harm the ozone layer.

The other options do not contribute to ozone layer depletion in the same manner. Carbon dioxide and methane, while important greenhouse gases, do not have the same destructive impact on ozone as chlorine does. Oxygen is a vital component of the atmosphere but does not play a role in ozone depletion.