Pollutant low altitude thermal inversion occurs in the winter. In this ** of the year the sun heats the soil less and the natural upward move of warm air decreases. Therefore the pollutants form a low altitude layer between the cold air layer near the ground and another layer of warmer air above. The pollutant layer over industrial areas or big urban concentrations reduces the ** of the sun' energy and the air bellow takes an even longer time to warm.
