Pressure Dependence
The relative humidity of an air-water system is dependent not only on the temperature but also on the absolute pressure of the system of interest. This dependence is demonstrated by considering the air-water system shown below. The system is closed (i.e., no matter enters or leaves the system).
If the system at State A is isobarically heated (heating with no change in system pressure) then the relative humidity of the system decreases because the saturated vapor pressure of water increases with increasing temperature. This is shown in State B.
If the system at State A is isothermally compressed (compressed with no change in system temperature) then the relative humidity of the system increases because the partial pressure of water in the system increases with increasing system pressure. This is shown in State C.
Therefore a change in relative humidity can be explained by a change in system temperature, a change in the absolute pressure of the system, or change in both of these system properties.
Read more about this topic: Relative Humidity
Famous quotes containing the words pressure and/or dependence:
“The mother whose self-image is dependent on her children places on those children the responsibility for her own identity, and her involvement in the details of their lives can put great pressure on the children. A child suffers when everything he or she does is extremely important to a parent; this kind of over-involvement can turn even a small problem into a crisis.”
—Grace Baruch (20th century)
“All charming people have something to conceal, usually their total dependence on the appreciation of others.”
—Cyril Connolly (1903–1974)