The air grader splits the incoming material into three fractions: acceptable material, coarse material (e.g., high density contaminants or wood particles of undesirable geometry such as needles, etc.) and material falling through the screen decks (mostly sand, minerals, glass, etc.). The product enters the air grader's suspension chamber via an airlock and a central tube. Agitator arms equalize the material uniformly over the perforated screen deck through which air is drawn. Different grades of separation are achieved by varying the air velocity. The heavy coarse material is moved to the outside of the grader and leaves the suspension chamber via airlocks. The accepted material is suspended in the air stream and separated from the air in high-efficiency cyclones.