The Dew Point is directly related to Absolute Humidity, the dew point is the temperature to which air must be cooled to become saturated with water vapor. When further cooled, the airborne water vapor will condense to form liquid water (dew). When air cools to its dew point through contact with a surface that is colder than the air, water will condense on the surface. Perma Pure uses the dew point as a way to measure dryness, because at a constant atmospheric pressure it relates to a constant value.