Moist Air - Specific vs. Relative Humidity
Specific humidity of moist air vs. relative humidity, water vapor and air density.
Humidity is the quantity of water vapor present in air. It can be expressed as an absolute, specific or a relative value.
If we know the relative humidity of the moist air and the water vapor density and the density of the air, the specific humidity can be expressed as:
x = 0.622 φ ρws / (ρ - ρws) 100% (1)
where
x = specific humidity (humidity ratio) of air vapor mixture (kgh2o/kgdry_air)
φ = relative humidity (%)
ρws = density of water vapor (kg/m3)
ρ = density of the moist or humid air (kg/m3)
