Saturated exit air humidity is the level of water vapor in air that has reached its saturation point, often expressed as the maximum amount of moisture the air can hold at a specific temperature. And is denoted by YS'. Saturated Exit Air Humidity is usually measured using the Kg of water vapour per Kg of air for Specific Humidity. Note that the value of Saturated Exit Air Humidity is always negative. Typically, the value of Saturated Exit Air Humidity is greater than -0.00000001.