Which gas is primarily responsible for ozone depletion?

Chlorofluorocarbons (CFCs) are primarily responsible for ozone depletion due to their chemical structure and stability. When released into the atmosphere, CFCs eventually rise to the stratosphere, where they are subjected to ultraviolet (UV) radiation. This exposure breaks down CFC molecules, releasing chlorine atoms.

These chlorine atoms can react with ozone (O₃) molecules, resulting in the destruction of ozone and the formation of oxygen (O₂). A single chlorine atom has the potential to destroy thousands of ozone molecules before it is removed from the stratosphere. This process significantly contributes to the thinning of the ozone layer, which is crucial for protecting the Earth from harmful UV radiation.

In contrast, while nitrogen dioxide, carbon dioxide, and methane have environmental impacts, they do not play a direct role in ozone layer depletion. Nitrogen dioxide is more associated with air quality issues, carbon dioxide is primarily a greenhouse gas associated with climate change, and methane contributes to global warming but does not significantly affect the ozone layer.