Use of membrane filters in air sampling.
Paulus-HJ; Talvitie-NA; Fraser-DA; Keenan-RG
Am Ind Hyg Assoc Q 1957 Sep; 18(3):267-273
Successful use of the aerosol type membrane filter for environmental studies in the field of occupational health over a period of 4 years was reported. The filters were composed of dry cellulose ester membrane, about 150 microns in thickness with 80 to 85 percent voids. It was composed of tubular pores with smaller diameters at the front or filtering surface than at the back. The filter, due to its brittleness, must be supported firmly or it will rupture from the high resistance to air flow. Light dust deposits may be counted directly on the filter whereas heavy deposits require the solution of the filter in a suitable solvent followed by standard dust counting procedures. Size of the particles collected has been determined by optical microscopy, electron microscopy, and by photometric sedimentation. Chemical analysis of some fumes and dusts has been improved through the removal of microquantities of toxic dusts and fumes from the filters by relatively simple procedures. The advantage of these filters over filter paper was demonstrated in studies of dust concentration by reflectance photometry.
Membrane-filters; Filtration; Air-sampling-techniques; Air-sampling-equipment; Air-quality-monitoring; Airborne-dusts; Metal-fumes; Aerosol-sampling
American Industrial Hygiene Association Quarterly