The classification of asbestos fibres by scanning electron microscopy and computer-digitizing tablet.
Platek-SF; Riley-RD; Simon-SD
Ann Occup Hyg 1992 Apr; 36(2):155-171
A classification method for asbestos (1332214) fibers using scanning electron microscopy (SEM) and computer assisted image digitized sizing was developed and evaluated. Seven groups of asbestos were tested. An SEM micrograph of a randomly selected field was taken at magnification of X2500, and referred to as the primary micrograph (PM). A second micrograph at reduced magnifications (RM) (x500 to x2000) included extremities of long fibers which extended beyond the PM field. The micrographs were further processed so that final magnifications of the PMs was x10,000 and that of the RMs was x8000. Individual measurements were made using a computerized digitizing tablet. Statistically, fiber size correlations for all the asbestos types was good between filters. Representation of fibrous and nonfibrous particles on a filter was possible with five sets of micrographs per filter. The authors conclude that their method permits reproducible and fairly accurate fiber and particulate size classification.
NIOSH-Author; Asbestos-fibers; Computers; Fibrous-dusts; Particulate-sampling-methods; Respirable-dust; Microscopic-analysis
Annals of Occupational Hygiene