Specific humidity is a method of expressing the amount of aqueous vapor in air by using a ratio of water vapor to dry air. Specific humidity is expressed as a ratio of kilogram of water vapor, m_w, per kilogram of air, m_w.

That ratio can be given as:

Partial pressure of water vapor and air can also be used to express the ratio.

See also; Humidity, Absolute humidity, Relative Humidity, Concentration.

External Links

• Glossary definition of specific humidity