ACH

ACH: Air changes per hour
Activated Charcoal: A highly absorbent form of carbon used to remove odors and toxic substances from liquids or gases.

Air Changes Per Hour (ACH) Number of times, per hour, an enclosure's total volume of air, equivalent to the volume of space, enters that space is exchanged. Air Exchange Rate The rate at which outside air replaces indoor air in a given space.

Air Changes per Hour (ACH)
The movement of a volume of air in a given period of time; if a house has one air change per hour, it means that all of the air in the house will be replaced in a one-hour period.
Air Purification Devices ...

The rate at which indoor air enters and leaves a building. Expressed as the number of changes of outdoor air per unit of time (air changes per hour (ACH), or the rate at which a volume of outdoor air enters in cubic feet per minute (CFM).

Ventilation Rate- The rate at which indoor air enters and leaves a building. Expressed as the number of changes of outdoor air per unit of time (air changes per hour (ACH), ...

See also: Air changes per hour, Water, Bacteria, Liquid, Environmental