What element in refrigerant contributes to ozone layer depletion?

The element that contributes to ozone layer depletion is chlorine. Chlorine is a key component in many ozone-depleting substances, particularly chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). When these compounds are released into the atmosphere, they eventually break down due to ultraviolet radiation, releasing chlorine atoms. Each chlorine atom can catalyze the destruction of thousands of ozone molecules before it is removed from the stratosphere, significantly impacting the ozone layer's ability to filter harmful ultraviolet radiation from the sun.

In contrast, fluorine, carbon, and hydrogen do not have the same destructive effect on ozone. While fluorine is often present in refrigerants as a stabilizing element, it does not have the same ozone-depleting properties as chlorine. Carbon, being a major constitutive part of hydrocarbons, typically does not contribute directly to ozone depletion, and while hydrogen is a part of various refrigerants, it is not associated with ozone layer damage in the same manner as chlorine. Thus, chlorine's unique destructive mechanism makes it the primary concern regarding ozone layer depletion.