Saturation vapor density
Saturation vapor density is a concept closely tied with saturation vapor pressure. It can be used to calculate exact quantity of water vapor in the air from a relative humidity Given an RH percentage, the density of water in the air is given by. Alternatively, RH can be found by. As relative humidity is a dimensionless quantity, vapor density can be stated in units of grams or kilograms per cubic meter.
For low temperatures, SVD can be approximated from the SVP by the ideal gas law: where is the SVP, is the volume, is the number of moles, is the gas constant and is the temperature in kelvins. The number of moles is related to density by, where is the mass of water present and is the molar mass of water. Thus, setting to 1 cubic meter, we get = = density.
The values shown at hyperphysics-sources indicate that the saturated vapor density is 4.85 g/m3 at 273 K, at which the saturated vapor pressure is 4.58 mm of Hg or 610.616447 Pa.
Therefore, for particular mole number and volume the saturated vapor pressure will not change if the temperature remains constant.
