Which group of compounds used in refrigerators and spray products can enter the atmosphere and destroy ozone?

Which group of compounds used in refrigerators and spray products can enter the atmosphere and destroy ozone?

• A. DDT
• B. Chlorofluorocarbons
• C. Neon
• D. Uranium

Answer: (B)

Ozone-depleting chemicals are those that can travel up to the stratosphere and participate in reactions that break down ozone. Chlorofluorocarbons are a group of compounds once common in refrigerators and spray products because they’re stable in the lower atmosphere. But in the high-energy environment of the stratosphere, UV light breaks them apart and releases chlorine atoms. Those chlorine atoms set off catalytic cycles that convert ozone (O3) into ordinary oxygen (O2), and the chlorine atoms are regenerated to keep destroying more ozone. Because one chlorine atom can destroy many ozone molecules, even small releases lead to significant thinning of the ozone layer. This is why these compounds posed a major ozone issue before safer alternatives were adopted. Other options don’t fit this mechanism: DDT is a pesticide, Neon is an inert gas, and Uranium is a radioactive element—none of which drive the ozone-depleting chemistry described.

Ozone-depleting chemicals are those that can travel up to the stratosphere and participate in reactions that break down ozone. Chlorofluorocarbons are a group of compounds once common in refrigerators and spray products because they’re stable in the lower atmosphere. But in the high-energy environment of the stratosphere, UV light breaks them apart and releases chlorine atoms. Those chlorine atoms set off catalytic cycles that convert ozone (O3) into ordinary oxygen (O2), and the chlorine atoms are regenerated to keep destroying more ozone. Because one chlorine atom can destroy many ozone molecules, even small releases lead to significant thinning of the ozone layer. This is why these compounds posed a major ozone issue before safer alternatives were adopted.

Other options don’t fit this mechanism: DDT is a pesticide, Neon is an inert gas, and Uranium is a radioactive element—none of which drive the ozone-depleting chemistry described.