get relative humidity from partial pressure ratio
Relative humidity can be expressed as the ratio of the vapor partial pressure of the air-to the saturation vapor partial pressure of the air at the actual dry bulb temperature. Relative humidity by partial pressure.Ï = pw / pws 100% (1).where.elative humidity can also be expressed as the ratio at actual mass of water vapor in a given air volume-to the mass of water vapor required to saturate at this volume. Relative humidity can be expressed as: Ï = mw / mws 100% (2c).