[AIVC, Air infiltration and ventilation glossary, 1992]:a quantity which expresses the ability of a ventilation system to reduce a pollution concentration relative to the feasible theoretical maximum performance.
[AIVC, Air infiltration and ventilation glossary, 1992]:a quantity describing how the ventilation ability of a system varies between different parts of a room.
[AIVC, Air infiltration and ventilation glossary, 1992]:the heat lost or gained by virtue of warm and/or humid air flowing into or leaking from a space.