What term describes the ratio of actual water vapor pressure to the saturated pressure at a given temperature?

The term that describes the ratio of actual water vapor pressure to the saturated pressure at a given temperature is relative humidity. This measurement is crucial in understanding how much moisture is present in the air compared to the maximum amount the air can hold at that specific temperature.

Relative humidity is expressed as a percentage, indicating the extent to which the air is saturated with water vapor. For instance, a relative humidity of 50% means the air holds half the amount of moisture it could hold at that temperature. This concept is fundamental in respiratory medicine, as it influences gas exchange and respiratory comfort.

Other terms, while related to humidity and moisture in the air, describe different aspects. Absolute humidity refers to the total mass of water vapor present in a given volume of air, without consideration of temperature. Specific humidity is the mass of water vapor per unit mass of air, and vapor density pertains to the mass of water vapor in a given volume of air, also without directly comparing it to the air's capacity for moisture. Understanding these distinctions solidifies the importance of relative humidity in atmospheric science and its application in respiratory care.