Which gas is primarily responsible for ozone destruction when released from refrigerants?

• A. Chlorine
• B. Oxygen
• C. Nitrogen
• D. Hydrogen

Answer: (A)

Chlorine. Refrigerants like CFCs and HCFCs contain chlorine, and when they are released and reach the upper atmosphere, sunlight breaks them apart and frees chlorine atoms. Those chlorine atoms kick off a catalytic cycle that repeatedly destroys ozone: chlorine reacts with ozone to form chlorine monoxide and O2, then chlorine monoxide reacts with a free oxygen atom to release chlorine again and produce more O2. Because the chlorine is regenerated, a single chlorine atom can destroy many ozone molecules, leading to significant ozone depletion. Oxygen itself isn’t a catalyst for destruction, and while nitrogen oxides can contribute to ozone loss in some contexts, they’re not the primary culprit from refrigerants, and hydrogen doesn’t play a major role here.