An air induction system for an engine to remove contaminants from intake air prior to delivery to the engine. The system includes a filtering unit having barrier filter panels attachable to a mounting frame. The filter panels are interchangeably usable. A juncture between first and second filter panels and the mounting frame is located at a region of relatively lower quantity of intake air flow. The juncture includes lugs on the filter panels which facilitate interchangeability. An opening above the filtering unit permits easy installation and removal of filter panels.