Abstract: Apparatus providing a work area at which one or several people can perform tasks requiring ultra-high efficient air filtration. The work area includes an air passageway throughwhich laminar flow of air occurs from a HEPA filter. The apparatus has a leading edge around the work area from which a certain of air flows in an enclosing and parallel relationship to the laminar flow air to extend the laminar air zone a distance beyond the work surface of the apparatus. The curtain air is passed through a HEPA filter prior to discharge. Dual air blowers supply air for the laminar flow air and the enclosing air curtain. The passageways for the two sources of air are in communication so that if necessary, one blower can be the source for both the laminar flow air and the air curtain. When both sources are in operation the communication means also serves to eliminate undesirable harmonics that might originate from either blower if it were to operate alone.