Which of the following is NOT a common atmospheric pollutant?

• A. Sulfur dioxide (SO_2)
• B. Carbon monoxide (CO)
• C. Ozone (O_3)
• D. Nitrogen gas (N_2)

Answer: (D)

Verified step by step guidance

1. Understand what constitutes a common atmospheric pollutant: these are substances found in the atmosphere that can harm human health, ecosystems, or materials.
2. Identify the listed substances and their roles in atmospheric chemistry: Sulfur dioxide (SO_2), Carbon monoxide (CO), and Ozone (O_3) are well-known pollutants produced by industrial processes, combustion, and photochemical reactions.
3. Recognize that Nitrogen gas (N_2) makes up about 78% of Earth's atmosphere and is chemically inert under normal conditions, meaning it does not typically act as a pollutant.
4. Compare the chemical nature and sources of each substance to determine which one does not fit the category of a pollutant.
5. Conclude that Nitrogen gas (N_2) is NOT a common atmospheric pollutant because it is a stable, naturally abundant gas essential for life and does not cause pollution.