Question

In air pollution, which of the following is/are classified as primary pollutants?

• A. Carbon monoxide (CO)
• B. Sulphur dioxide (SO2)
• C. Ozone (O3)
• D. Nitrogen dioxide (NO2)

Hint:

Primary pollutants are directly emitted into the atmosphere, while secondary pollutants like ozone are formed through chemical reactions involving primary pollutants.

Answer 1

The Correct Option is A, B, D

Primary pollutants are substances directly emitted into the atmosphere that can cause harm or discomfort. These include:
- Carbon monoxide (CO), which is produced by incomplete combustion of carbon-containing fuels.
- Sulphur dioxide (SO2), which is primarily released from burning fossil fuels.
- Nitrogen dioxide (NO2), which is produced during combustion processes, especially in vehicles and power plants.
Ozone (O3), however, is a secondary pollutant formed by chemical reactions in the atmosphere involving primary pollutants such as nitrogen oxides (NOx) and volatile organic compounds (VOCs). Therefore, the correct answer is (A), (B), and (D).
Final Answer: \[ \boxed{(A), (B), (D) \, \text{Carbon monoxide (CO), Sulphur dioxide (SO2), Nitrogen dioxide (NO2).}} \]