# Moist Air and Degree of Saturation

## Humidity ratio of moist air to humidity ratio of saturated moist air

**Degree of Saturation** is the ratio of the humidity ratio of moist air - to the humidity ratio of saturated moist air at the same temperature and pressure.

The Degree of Saturation can be expressed as

μ = x / x_{s}(1)

where

μ= degree of saturation

x= humidity ratio of the air (kg_{h20}/kg_{dry_air})

x_{s}=humidity ratioof the air at saturation at the same temperature and pressure(kg_{h20}/kg_{dry_air})

The degree of saturation can also be expressed as:

μ = φ (p_{a}- p_{ws}) / (p_{a}- p_{w})(2)

where

μ= degree of saturation

φ= relative humidity (%)

p_{w}= vapor pressure (mbar)

p_{ws}= saturation vapor pressure at the actual dry bulb temperature (mbar)

p_{a}= atmospheric pressure of moist air (mbar)