Empirical calibration of a laser particle size analyzer for silica dust.
Am Ind Hyg Assoc J 1982 Mar; 43(3):145-148
An empirical calibration procedure for nonideal aerosols using laser particle size analyzers (LPSAs) was described. The procedure was based on calibrating the LPSA against silica (7631869) dust profiles determined by scanning electron microscopic analysis. A plot of signal pulse voltage versus particle size was developed, which was based on uncorrected signal pulse voltages measured for a test silica aerosol. This was compared with the particle size distribution curve obtained with the electron microscope for the same aerosol. From this comparison, the LPSA optical particle size and electron microscope geometric particle size at a given cumulative fraction level could be determined. A given LPSA optical particle size in the original curve could then be replaced with an electron microscope geometric particle size having the same light scattering intensity. This resulted in a new empirical calibration curve for the LPSA. When tested against a NIOSH silica dust aerosol, the geometric median diameter of the particle size distribution obtained by the LPSA was 0.48 microns with a standard geometric deviation of 1.6. The geometric median diameter of the distribution obtained by the electron microscope was 0.50 microns with a standard deviation of 1.6. The authors note that in order to develop a reliable calibration curve for the LPSA, a sufficient number of particle counts must be obtained in the upper size range, and that operator techniques when using the scanning electron microscope must be standardized.
NIOSH-Author; Analytical-methods; Analytical-instruments; Airborne-dusts; Mineral-dusts; Laboratory-testing; Dust-analysis; Optical-analysis; Mathematical-models; Microscopic-analysis
American Industrial Hygiene Association Journal