4.1. Basic principles
4.1.4. Humidity

Humidity

Definitions

Absolute humidity

... is the mass of water vapour present in a given volume of air

Relative humidity

... the mass of water in a given volume of air as a percentage of the mass required to saturate that given volume of air at the same temperature.

Thus,

From the ideal gas equation,

Normal values

Maximum absolute humidity @ 0 C
= 4.8 mg/L

Maximum absolute humidity @ 20C
= 17 mg/L

Maximum absolute humidity @ 37C
= 44 mg/L

Absolute vs relative humidity

Absolute humidity doesn't change with temperature.

But,
Saturated absolute humidity varies with temperature

Thus,
Relative humidity also varies with temperature

Keywords:  Humidity ; Hygrometer
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Created20050528
Reviewed20050528


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