How do hydrochlorofluorocarbons (HCFCs) impact the ozone layer?

Hydrochlorofluorocarbons (HCFCs) impact the ozone layer primarily by depleting stratospheric ozone, albeit to a lesser extent than chlorofluorocarbons (CFCs). The significance of this is rooted in the chemical properties of HCFCs. Like CFCs, HCFCs release chlorine atoms in the stratosphere when they are broken down by ultraviolet (UV) radiation. These chlorine atoms can catalytically destroy ozone molecules; however, HCFCs have a shorter atmospheric lifespan and thus a lower ozone depletion potential compared to CFCs.

Since HCFCs have been developed as transitional substitutes for CFCs, they were chosen partly because they contribute less to ozone depletion while still posing some risk. Over time, as international agreements like the Montreal Protocol have phased out CFCs, the use of HCFCs was expected to significantly decrease as well, with the goal of mitigating their impact on the ozone layer. Therefore, the correct answer reflects the understanding that while HCFCs do pose a risk, their effect is comparatively less severe than that of their predecessors, the CFCs.