What is the first step in the process of ozone depletion?

The initial step in the process of ozone depletion involves chlorofluorocarbons (CFCs) being released into the atmosphere, particularly through products like aerosols, refrigerants, and foam-blowing agents. These CFCs are stable compounds and can persist in the atmosphere for a long time, allowing them to slowly migrate to the stratosphere.

Once in the stratosphere, CFCs are subjected to ultraviolet (UV) radiation, which breaks them down and releases chlorine atoms. This released chlorine plays a pivotal role in the destruction of ozone molecules. The interaction begins with the presence of CFCs in the stratosphere; without their initial release into this layer of the atmosphere, the subsequent processes of ozone depletion cannot occur.

In contrast, options that mention reactions involving water or the breakdown of ozone occur later in the process and are contingent upon the initial presence of CFCs in the stratosphere. Additionally, while chlorine can be released through other compounds like methane, it is not the primary path for the ozone depletion mechanism initiated by CFCs. Thus, understanding this sequence highlights the importance of CFCs as the starting agents of ozone layer destruction.