Asbestos measurement in remote ambient air

In the study described, Spurny's (1969) Nuclepore filters with a mean pore diameter of 0.4 microns and a filter diameter of 47 mm were used to sample small chrysotile fibers and fibrils in ambient air. In nonpolluted regions, it proved possible to sample 50 cu m of air on a single filter. Under these conditions, the obscuring effect of nonfibrous particles was negligible. In highly polluted areas, the sampling volume dropped to below 10 cu m. Identification of fibers may be hindered by overlapping with isometric particles. The need for a method that would provide adequate preseparation of isometric particles and fibers is indicated.