Generation of replicate asbestos aerosol samples for quality assurance.
Appl Ind Hyg 1987 May; 2(3):114-118
A method was described for preparing replicate asbestos (1332214) samples needed for the Proficiency Analytical Testing (PAT) program. The method utilized an aerosol generation technique using a two component fluidized bed. A bronze powder bed material was used, and an aerosol charge neutralizer was included. The aerosol concentration produced by the generator was able to provide sufficient asbestos for the 320 samples in the chamber. In the overall sample preparation stage, grinding and wet sieving of chrysotile (12001295) was the most tedious and least well defined step. However, the less than 200 mesh material seemed to give aerosol filter samples resembling some field samples. The fibers were well dispersed with little clumping. Length and diameter distributions were closer to those of field samples than distributions obtained in traditional liquid suspension methods. There were no extremely long fibers such as had been seen in samples prepared by liquid suspension. Reasonable appearing samples were also obtained using crocidolite (12001284) and amosite (12172735). The reproducibility of the aerosol generated samples was determined by image analysis fiber counting and found to be good. Results between laboratories showed somewhat closer agreement for the aerosol generated samples than for those prepared by the traditional suspension generation approach. The authors conclude that this aerosol generation technique is suitable for producing asbestos fiber samples of low variability and reasonable resemblance to field samples to be used in testing a laboratory's fiber counting accuracy.
NIOSH-Author; Airborne-fibers; Asbestos-fibers; Air-sampling; Sampling-methods; Sample-preparation; Aerosol-generators; Safety-research; Aerosol-particles; Statistical-quality-control
1332-21-4; 12001-29-5; 12001-28-4; 12172-73-5
Applied Industrial Hygiene