Referring now to FIG. 4, there is illustrated the air filtration system embodiment designated by the numeral 30 which includes a generally rectangular box shaped outer frame or cabinet 62 which may be constructed of a conventional material, such as steel or aluminum and characterized by a top wall 64, a bottom wall 66, an end wall 68 and opposed sidewalls 70 and 72, see FIGS. 5 and 6, also.