Patent ID: 6976911

Claim:
A filtration system for protecting occupants in an enclosed structure from airborne contaminants, comprising: an enclosure having a first opening and a second opening, wherein the first opening is linked to a HVAC unit and the second opening is an intake for outside air to pass through the HVAC unit; a filtration assembly mounted within the enclosure between the first and second opening; a blower mounted within the enclosure and draws the outside air from the second opening to pass through the filter assembly, and an adaptor that connects the first opening of the enclosure to the HVAC unit, at least a set of louvers mounted within the adaptor and configured to move between an open and closed position, wherein unfiltered outside air is permitted to enter the HVAC system when the louvers are in the open position and unfiltered outside air is prevented from entering the HVAC system when the louvers are in the closed position.