What term describes the ratio of water vapor in a volume of air to the amount of vapor that air can hold at the same temperature when saturated?

Relative humidity is the term that describes the ratio of water vapor in a volume of air to the maximum amount of vapor that air can hold at the same temperature when saturated. This measurement is typically expressed as a percentage. For instance, if the relative humidity is 60%, it means the air currently holds 60% of the maximum amount of water vapor it can contain at that temperature. This concept is essential in mine ventilation as it directly affects the comfort of workers and the overall safety of the environment by influencing condensation, airflow, and the potential for mold growth.

Absolute humidity, on the other hand, measures the actual amount of water vapor in a specific volume of air regardless of that air's temperature. Specific humidity represents the mass of water vapor per unit mass of air, which also differs from relative humidity. The term saturation ratio relates to the comparison of the actual humidity to the saturation humidity but is not commonly used as the correct term to describe the concept of relative humidity. Understanding relative humidity is crucial for assessing and managing air quality in mine environments.