Exhaust effectiveness indicates how effectively contaminated air can be removed from a space, whereas air change effectiveness indicates how effectively distribute fresh air into the space. It is intended to describe the exhaust effectiveness based on the residual-life-time of contaminant in the context of logical extension of supply effectiveness based on LMA. It is proved theoretically that the room-mean values of LMA and LMR are identical, even though their local distributions are different from each other depending on inlet/outlet configurations. It is necessary to define ventilation effectiveness clearly so as to distinguish supply and exhaust effectiveness in describing local distributions in a room. Overall ventilation effectiveness, however, need not be distinguished, since both of the room averages of supply and exhaust indices are identical. They are dependent on the airflow pattern only, but not on the contaminant distribution in the space.
Exhaust effectiveness based on residual lifetime of contaminant in a ventilated space
31st AIVC Conference " Low Energy and Sustainable Ventilation Technologies for Green Buildings", Seoul, Korea, 26-28 October 2010