What is the phenomenon called when smoke hangs low to the ground on a cool, damp, windless day?

The phenomenon where smoke hangs low to the ground on a cool, damp, windless day is known as a smoke inversion. This occurs when a layer of warmer air traps cooler air (and the smoke within it) near the surface, preventing it from rising. On such days, the stable atmosphere does not allow for the mixing of air layers, leading to the accumulation of smoke at lower levels.

While fog is often associated with damp conditions, it typically involves condensation of water vapor rather than smoke particles. A heat wave, on the other hand, refers to prolonged periods of excessively hot weather and is not relevant in this context. A backdraft is a specific fire phenomenon caused by sudden airflow into a space that is depleted of oxygen, leading to explosive combustion, but it does not relate to the behavior of smoke in low-lying conditions. Understanding smoke inversion is crucial for firefighters, as it impacts visibility and air quality during operations.