Relative humidity (abbreviated RH) is the ratio of the partial pressure of water vapor to the equilibrium vapor pressure of water at the same temperature. Relative humidity depends on temperature and the pressure of the system of interest.
Definition[edit]
The relative humidity left(phi
ight) of an air-water mixture is defined as the ratio of the partial pressure of water vapor (H2O) left({e_w}
ight) in the mixture to the equilibrium vapor pressure of water left({{e^*}_w}
ight) at a given temperature.
Relative humidity is normally expressed as a percentage and is calculated by using the following equation:[1]
phi = {{e_w} over {{e^*}_w}} imes 100\%