Air - Humidity Ratio
Calculate the humidity ratio of moist air based on vapor partial pressure and atmospheric pressure. The humidity ratio expresses the mass of water vapor per unit mass of dry air.
Air - Humidity Ratio
The humidity ratio of moist air can be expressed as the ratio of the mass of water vapor to the mass of dry air.
Humidity Ratio by Vapor Partial Pressure
Based on the Ideal Gas Law, the humidity ratio can be expressed as:
x = 0.62198 × pw / (pa - pw)
Where:
- x = humidity ratio (kg water/kg dry air)
- pw = partial pressure of water vapor (Pa)
- pa = atmospheric pressure (Pa)
For saturated air:
xs = 0.62198 × pws / (pa - pws)
Where:
- xs = maximum saturation humidity ratio
- pws = saturation pressure of water vapor (Pa)