The paper gives results of an evaluation of the fractional filtration efficiency of air cleaners. The test duct accepts air cleaners up to 610 x 610 mm in size and provides test flow rates up to 470 L/s. Filtration efficiency is computed from upstream and downstream aerosol concentration measurements performed with a differential mobility analyzer, a laser aerosol spectrometer, and a white-light optical particle counter. The measurements cover the particle diameter size range from 0.0l to 3 micrometer in 16 sizing channels. Air cleaners tested include furnace filters, pleated filters, and statically charged panel filters. The efficiency of the air cleaners was often found to be highly dependent on particle size and dust load. A minimum in efficiency was frequently observed in the 0.1 to 0.5 micrometer range. The presence of a dust load on the air cleaners frequently increased their efficiency. However, for some air cleaners, little change or a decrease in efficiency accompanied the dust loading. The common furnace filter was seen to have a fractional efficiency of less than 10% over much of the 0.01 to 1 micrometer size range.

Project Officer: Leslie E. Sparks. Performing Organization: Research Triangle Institute. "Presented at IAQ '93, Helsinki, Finland, 7/4-8/93"--Technical Data Report insert. EPA/600/A-93/234. AEERL-P-1043. PB93-236636. Includes bibliographical references (leaf 6) and abstract.