Abstract: A portable and mobile multi-stage filtering system is disclosed capable of filtering particulate of the size of one micron. An external canister filter capable of filtering down to at least 0.5 microns is connected to and located external to the cabinet of the airtight filtering system. The cabinet contains a centrally located high speed motor driving a high capacity vacuum pump completely surrounded by thermal and acoustical insulation. The air filtering path includes a plurality of baffles defining a serpentine path for exhausting the air into a series of plenums of increasing volume which communicates with a ULPA filter capable of filtering down to 0.12 micron. The plenums are also surrounded by acoustical and thermal insulation which has the effect of lowering the noise of the filtering system and increasing the efficiency of the total system.