We spend a lot of time, energy, and money controlling the humidity in our growing areas, and there's a lot of debate about the relative efficacy of foggers, cool-mist-, warm-mist-, and ultrasonic humidifiers, humidity trays, and the like.

I'm not really sure of the real value of this JavaScript calculator, but it's interesting to see just how much water the air can hold.  The values are approximations only, as differences in air pressure can affect these numbers, and it assumes there is absolutely no entrance or escape of air from the room.