Relative Humidity (RH) is expressed as?

Relative Humidity (RH) is expressed as a percentage, which quantifies the amount of water vapor present in the air relative to the maximum amount of water vapor that the air can hold at a given temperature. When RH is reported as a percentage, it indicates how close the air is to being fully saturated with moisture. For example, an RH of 50% means the air is holding half of the moisture it could potentially hold at that specific temperature.

While the concept of relative humidity involves a ratio of water vapor to the total air in the atmosphere, this ratio is specifically represented as a percentage to make it easier to understand and apply in various contexts, such as weather reports and indoor air quality assessments. The understanding of relative humidity is crucial for home inspections because high humidity levels can lead to mold growth, structural damage, and decreased indoor air quality.

The other options refer to different concepts. Moisture in solid form relates to substances like ice or frost, which doesn't pertain to the definition of relative humidity. A unit of pressure is not a measure of humidity; rather, relative humidity pertains to the moisture content in the air. Thus, expressing RH as a percentage provides clarity and relevance for assessing air quality and comfort levels within indoor environments.