The , Air Stagnation map shows areas where the atmosphere is likely to have more or less air stagnation for the current day. This affects air quality in that region, particularly in urban areas.

Air stagnation is a phenomenon which occurs when the same air mass remains over an area for an extended period of time. Usually this is because light winds and a lack of precipitation cannot "clean" the air of pollutants, either gaseous (like ozone) or particulate (like soot or dust). In the United States, the National Weather Service issues an Air Stagnation Advisory when these conditions are likely to occur.