Calculation of the mean yearly mixing height over urban areas, from air pollution data

Conditions for the usefulness of the ventilation-volume or box model in the representation of long-term averages of pollutant concentrations are discussed. It is shown that yearly averages of mixing heights can be calculated from air pollutant concentration data without reference to meteorological observations. With no pretence to high accuracy, average mixing heights thus obtained are adequate to rapidly characterize an urban area in the low, medium or high bracket of pollutant concentrations. Estimates of yearly average mixing heights for six French and two Japanese towns are given.