How does a temperature inversion affect urban air quality and ground-level pollutant concentrations?

• A. Inversion enhances vertical mixing and disperses pollutants.
• B. A temperature inversion traps pollutants near the surface by suppressing vertical mixing, leading to elevated concentrations and smog.
• C. Inversions have no impact on air quality.
• D. Inversions pull pollutants away from the city.

Answer: (B)

A temperature inversion creates a stable layer in the lower atmosphere where a warmer air mass sits above cooler air near the ground. This cap prevents air from rising and dispersing pollutants, so emissions from cars, factories, and other sources stay trapped close to the surface. The result is higher ground-level concentrations of pollutants and more smog, especially on calm days when the air isn’t stirred. That’s why a temperature inversion leads to poorer urban air quality. It does not enhance vertical mixing, nor does it have no impact or pull pollutants away from the city; instead it suppresses mixing and concentrates pollutants near the ground.