Air moved through ceiling-mount air purifiers is cleansed as it passes through the HEPA filter. This helps reduce airborne pathogens in a variety of high-risk areas, including exam rooms, waiting areas, and more. These units can be utilized to create either negative or positive pressure environments. Our ceiling-mount air purifiers offer: 99.97% HEPA filtration MERV 8 pre-filters (to protect and prolong the life of the HEPA filter) Quiet operation HEPA exhaust units create negative pressure and help contain infectious airborne pathogens HEPA supply units create positive pressure and help create protective environments A variety of speed control options Simple installation and maintenance.