Environmental Protection Agency (EPA) MVAC Certification

Which agent is primarily responsible for stratospheric ozone depletion?

1. Carbon Dioxide

2. Chlorine Dioxide

3. Chlorine Monoxide

4. Ozone itself

The correct answer is: Chlorine Monoxide

Chlorine monoxide is primarily responsible for stratospheric ozone depletion because it plays a significant role in the chemical processes that break down ozone molecules in the stratosphere. When chlorofluorocarbons (CFCs) and other ozone-depleting substances (ODS) are released into the atmosphere, they eventually rise to the stratosphere where UV radiation breaks them down, releasing chlorine atoms. These chlorine atoms can react with ozone (O3), leading to the formation of chlorine monoxide (ClO) and the depletion of ozone. Since a single chlorine atom can break down thousands of ozone molecules, the impact of chlorine monoxide on stratospheric ozone is profound, making it a key agent in ozone depletion. In contrast, carbon dioxide, chlorine dioxide, and ozone itself do not directly contribute to the same extent to the depletion of stratospheric ozone as chlorine monoxide does. Carbon dioxide is mainly a greenhouse gas and does not have the reactive properties necessary for ozone depletion. Chlorine dioxide is a different chlorine compound that does not play a significant role in ozone depletion. Ozone, while affected by depletion, does not have a role as a depleting agent but rather is the substance being depleted. Thus, chlorine monoxide's direct involvement