Gaseous Pollutants Explained

Gaseous pollutants are substances in the atmosphere existing in a gas state that can negatively impact health and the environment. They differ from particulate pollutants, which are solid or liquid particles suspended in the air.

Analysis of Atmospheric Pollutants

We need to identify the option that is NOT a gaseous pollutant:

• Tropospheric ozone: Exists as a gas ($O_3$) in the atmosphere.
• Sulphur dioxide: A well-known gaseous pollutant ($SO_2$).
• Atmosphere aerosols: These are fine solid or liquid particles (like dust, soot, salt) suspended in the air, not a gas. They are classified as particulate matter.
• Nitrogen dioxide: Exists as a gas ($NO_2$) and is a common air pollutant.

Conclusion on Non-Gaseous Pollutant

Atmosphere aerosols are composed of particles, not gas. Therefore, they are the correct answer as the option that is not a gaseous pollutant.