Establishes a test procedure for evaluating the performance of air-cleaning devices as a function of particle size. Describes a method of laboratory testing to measure the performance of general ventilation air cleaning devices. This is the third public review for this standard. It previously appeared in the April 12, 1996 and November 8, 1996 issues of Standards Action. It is being resubmited now due to substantive changes made to the original submittal.