On the filtration of fibrous aerosols

Basic peculiarities occuring during the filtration of fibrous aerosols are discussed. Using aerosols of very fine asbestos fibers, filtration efficiencies of some analytical filters -Nuclepore and Millipore filters - were investigated. The collection efficiences were measured by means of electron microscopy and radiolabeled asbestos fibers. The collection efficiencies, which depended on the pore sizes of the filters and on the fiber form of the used aerosol, lay in the range of about 40-99.9%. A special problem discussed is the orientation of fibrous particles in the vicinity of filter pore entrances. (author)