DEFINITION:

Product of the mixing height (m) and the transport wind speed (m/s) used as a tool for air quality forecasters to determine the potential of the atmosphere to disperse contaminants such as smoke or smog. The University of Washington - Dept. of Atmospheric Sciences uses the product of the planetary boundary layer (PBL) height (m) and 20m wind speed (m/s) to calculate the ventilation index.

Below is a table to describe the values of the Ventilation Index. There are many different interpretations of this value as the description (i.e. GOOD, POOR) is very subjective.