Which element in CFC and HCFC refrigerants is responsible for destroying ozone in the stratosphere?
Environmental impacts · EPA 608 Core. The correct answer, and the reasoning behind it.
How CFCs and HCFCs destroy stratospheric ozone, and what that does to health and the environment.
The question
Which element in CFC and HCFC refrigerants is responsible for destroying ozone in the stratosphere?
- Fluorine
- Carbon
- ChlorineCorrect answer
- Hydrogen
Why “Chlorine” is correct
CFCs and HCFCs contain chlorine. When ultraviolet light breaks these molecules apart high in the stratosphere, the chlorine atoms that are freed attack ozone. That is why chlorine-free refrigerants such as HFCs have an ozone depletion potential of zero.
Source: EPA: Test Topics
Why the other answers are wrong
- Fluorine — Fluorine is in CFCs, HCFCs and HFCs alike, yet HFCs do not deplete ozone, so fluorine is not the culprit.
- Carbon — Carbon is the backbone of the molecule but does not attack ozone.
- Hydrogen — Hydrogen is what makes HCFCs break down sooner in the lower atmosphere; it does not destroy ozone.
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