Dry-basis humidity

Absolute humidity Y Mass of water (or solvent) vapor carried by unit mass of dry air (or other carrier gas). It is also known as the mixing ratio, mass ratio, or dry-basis humidity. Preferred units are Ib/lb or kg/kg, but g/kg and gr/lb are often used, as are ppm and ppb (parts per million/billion by weight) ppm = 10 Y, ppb = 10 Y. 

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