Humidity

The word humidity as used on con­nection with refrigeration, air conditioning, and weather information refers to water vapor or moisture contained in the air. Air absorbs moisture (water vapor) the amount depending on the pressure and temperature of the air. The higher the temperature of the air, the more moisture it can absorb. The higher the pressure of the air, the smaller the amount of moisture it can absorb. The amount of moisture carried in a sample of air, compared to the total amount which it can absorb at the stated pressure and temperature, is called relative humidity.