Which term describes the amount of water in a given volume of air?

• A. Humidity
• B. Relative humidity
• C. Air mass
• D. Wind

Answer: (A)

Humidity is the term for the water vapor present in air. It describes how much moisture is in the air overall. Relative humidity, by contrast, is a percentage of how close the air is to being saturated, which depends on temperature, so it doesn’t directly state the actual amount of moisture. Air mass refers to the amount of air itself, not its moisture content, and wind is simply the movement of air. While absolute humidity or specific humidity give precise amounts per volume or per mass, the general term used to describe the water content in air is humidity, making it the best fit here.