What is atmospheric inversion?

Atmospheric inversion is when the temperature in the atmosphere inverts, making the temperature rise instead of fall in areas higher above the ground. Inversions occur most commonly in the afternoon due to the ground emitting more radiation than it is receiving from the waning sunlight.

Another cause of atmospheric inversions is cold winds entering valleys from hillsides as well as anticyclones.

One quality of atmospheric inversion includes low air that is heavy and cold, which suppresses turbulence and the likelihood of upward currents. Pollutants can become trapped for longer times in the inversion layers due to the layer inhibiting both vertical and horizontal diffusion.