The Air-Care EPA Portable Bio Air Scrubber with UVC and HEPA is designed for use in schools, doctors’ offices, business offices and larger meeting rooms. This unit features a 4-stage HEPA filter, which provides 99.97% at 0.3 microns filtration. It also offers electrostatic, antimicrobial MERV 8 pre-filters plus 50 watts of UVC germicidal lights. Heavy-duty casters allow easy transportation and maneuvering. Note: The size and number of machines needed depends on the volume of the space being cleaned as well as how many Air Changes per Hour (ACH) are required by local regulation. As a starting point, calculate the square footage of the room or rooms, and multiply by the ceiling height. It is generally recommended to have 3 to 4 air changes per hour in occupied areas.