Which gas is primarily responsible for ozone depletion?

The primary gas responsible for ozone depletion is chlorofluorocarbons (CFCs). These compounds were widely used in refrigeration, air conditioning, and aerosol propellants. When released into the atmosphere, CFCs eventually reach the stratosphere, where they are broken down by ultraviolet (UV) radiation, releasing chlorine atoms. These chlorine atoms are highly reactive and can destroy ozone molecules, leading to significant reductions in the ozone layer. The depletion of ozone is concerning because it plays a critical role in blocking harmful UV radiation from reaching the Earth's surface, which can lead to increased skin cancer rates and other environmental issues.

In contrast, carbon dioxide primarily contributes to global warming rather than ozone layer depletion, while nitrous oxide and methane are significant greenhouse gases but do not have the same direct impact on the ozone layer as CFCs do. This distinction highlights the specific role that CFCs play in the atmospheric chemistry that affects ozone depletion.