What is the key agent responsible for stratospheric ozone depletion?

The substance primarily responsible for stratospheric ozone depletion is chlorofluorocarbon (CFC). CFCs are stable compounds that can ascend to the stratosphere, where they are broken down by ultraviolet radiation, releasing chlorine atoms. These chlorine atoms participate in a series of reactions that lead to the destruction of ozone molecules.

While chlorine monoxide does play a role in the ozone depletion process, it is actually formed from the breakdown of CFCs in the stratosphere. Therefore, while the presence of chlorine monoxide is crucial within the reaction cycle contributing to ozone loss, it is not the primary agent responsible for the initial depletion.

Bromine is also a potent ozone-depleting compound, but it is less prevalent than CFCs. Carbon dioxide does not contribute to ozone layer depletion; instead, it is more associated with global warming as a greenhouse gas.

In summary, the key agent responsible for stratospheric ozone depletion is CFCs, as they release chlorine, which is directly involved in the breakdown of ozone.