What is the condition of air at 100% relative humidity (RH)?

When air reaches 100% relative humidity, it means that the air is saturated with moisture. At this point, the air cannot hold any more water vapor at a given temperature and pressure, resulting in a state where the air is filled to its capacity with water vapor. This condition can lead to the formation of water droplets, fog, or clouds, as any additional moisture may condense out of the air. Saturation is key in understanding humidity and its effects on temperature, comfort, and condensation processes in buildings.

In contrast, other conditions, such as high pressure, dry air, or the notion of condensed without specific context, do not accurately describe the state of air when it is at 100% relative humidity. High pressure can occur at varying humidity levels; dry means there isn’t enough moisture present, and the term condensed typically refers to the state that occurs when air cools and water vapor transforms into liquid, rather than indicating the situation at full saturation.