ormal circulation of air can help keep the pollution at ground level from building up. The temperature of the air is usually warmer near the Earth and gets cooler with increasing altitude. The circulation cycle occurs because the sun warms the Earth and the air close to it during the day. In the evening, the warm air rises as the Earth and the air close to the ground cools.

This circulation of air takes pollutants higher in the atmosphere where they disperse. Sometimes pollution is trapped near the Earth because of a thermal inversion which occurs when a layer of warm air traps cooler air and smog close to the ground and keeps it from escaping into the atmosphere. This layer of cool air is "out of order" since warm air is usually closer to the Earth.

Next - Visibility - Look into the light ...

  Visibility

  Acid Rain/Snow

  Air Pollution Advisories

  Air Pollution Advisories

Tell me more...
Inversion layers and how they work.