In mine ventilation, the standard density of air for mine ventilation work is considered to be 0.075 lb/ft₃(1.2014 kg/m₃). This is based upon the weight of 1 ft₃(0.028 m₃) of dry air at 70 degrees F (21.1 degrees C) at a sea-level pressure of 29.9 in (759 mm) of mercury.