Question

which of the following is not an air pollutant? carbon monoxide ozone oxygen sulfur oxides

Explanation:

To determine which is not an air pollutant, we analyze each option:

• Carbon monoxide (CO) is a toxic gas and an air pollutant.
• Ozone ($O_3$) at ground level is a pollutant (though beneficial in the stratosphere).
• Oxygen ($O_2$) is essential for life and not an air pollutant.
• Sulfur oxides (e.g., $SO_2$) contribute to acid rain and are pollutants.

Answer:

C. oxygen