Time Required for Removal of Airborne Contaminants from a Room

 

volume of a room in cubic meters =

= (breadth in meters) * (width in meters) * (height in meters)

 

air exchanges for room per hour =

= (cubic meters of air moved per minute) * 60 / (volume of room in cubic meters)

 

X =

= (-1) * LN(((100 percent) – (efficiency in percent)) / 100)

 

number of minutes to achieve a level of removal efficiency =

= X * 60 / (air exchanges per hour)

 

This assumes ideal mixing of air within the room, without dead spaces. In most rooms mixing is not ideal, and the air exchanges is multiplied by a factor that reflects the level of mixing achieved.