It is a critical factor in environmental control for many situations.

Controlling the humidity in food storage, grain for example, helps protect against decay.

Maintaining a relative humidity of around 50% provides a comfortable and healthy environment so humidity is a common measurement in office and domestic air conditioning systems.

Computer rooms and semiconductor production areas need highly controlled levels of humidity. Too high levels of moisture will damage circuits but too low humidity increases the risk of damage from static electricity.

Plants in nurseries and greenhouses will develop mould and disease if the humidity levels are too high, but moisture is essential to maintain healthy growth.