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EPA 608 Core Exam·Ozone Depletion

Where is the ozone layer located?

  1. ATroposphere
  2. Stratosphere
  3. CMesosphere
  4. DThermosphere

Correct answer

Stratosphere

Why

The ozone layer is located in the stratosphere, approximately 10-30 miles above Earth's surface.

The concept behind this question

Ozone depletion potential (ODP) measures how much damage a compound does to stratospheric ozone, and chlorine is the culprit. CFCs carry the most chlorine and the highest ODP, HCFCs carry less and are transitional, and HFCs contain no chlorine and have an ODP of zero. Zero ODP is not the same as harmless — many HFCs have high global warming potential (GWP), which is what the more recent phase-down addresses.

More questions on this topic

Exam-style practice question. Not an official EPA exam question.