The term for the temperature-specific measure of moisture in air, defined as the ratio of water vapor to saturation at that temperature, is what?

• A. Relative Humidity (RH)
• B. Dew Point
• C. Vapor Pressure
• D. Humidity

Answer: (A)

Relative humidity is the percentage of moisture in the air relative to the maximum amount the air can hold at that temperature. Since air’s capacity to hold water vapor increases with temperature, the same amount of water vapor corresponds to different percentages as temperature changes. The ratio of the actual water vapor to the saturation amount at that temperature, expressed as a percent, is exactly relative humidity. Dew point is the temperature at which air becomes saturated and condensation forms; vapor pressure is the actual pressure exerted by water vapor in the air; humidity is a general term for moisture and doesn’t specify this specific ratio.