A continuous wash of (HEPA, ULPA, or PTFE) filtered air moving horizontally across the work area. The uniform stream of filtered air moves forward over the work surface from the rear of the work area. The air flows across the work surface (product and/or application) directly at the user and exhausts into the surrounding space. Horizontal units are appropriate when the product and process at the work surface must come first in line with the clean air stream. Available in stainless steel construction, quoted on request.