Why does a temperature inversion trap smog and prevent it from dispersing?

• A. Because the cooler air at the surface rises quickly, carrying smog away from the city.
• B. Because a layer of warm air above cooler air prevents vertical mixing, keeping pollutants near the ground.
• C. Because the warm air at the surface absorbs pollutants, removing them from the atmosphere.
• D. Because temperature inversions increase wind speed, which disperses smog horizontally.

Answer: (B)

Verified step by step guidance

1. Understand what a temperature inversion is: Normally, air temperature decreases with altitude, allowing warm air near the surface to rise and mix with cooler air above.
2. Recognize that during a temperature inversion, this pattern reverses, and a layer of warm air sits above cooler air near the surface.
3. Analyze how this warm layer acts like a lid, preventing the cooler air (and any pollutants it contains) from rising and dispersing vertically.
4. Realize that because vertical mixing is inhibited, pollutants such as smog become trapped near the ground, leading to higher concentrations.
5. Conclude that this trapping effect explains why smog remains close to the surface during a temperature inversion, worsening air quality in the affected area.