Determination of the submicrometer fraction of beryllium aerosol.
Berakis-M; McCawley-M; Kent-M
American Industrial Hygiene Conference and Exposition, May 20-25, 2000, Orlando, Florida. Fairfax, VA: American Industrial Hygiene Association, 2000 May; :74
Controversy currently surrounds the choice of both the correct exposure limit for beryllium and the means of measuring that limit. Recent evidence has indicated that there might be a link between the number concentration of beryllium particulate and disease. Because number concentration is strongly influenced by smaller particle sizes, a determination of the size distribution of the processes that generates the aerosol was undertaken. This investigation was done to establish the relative quantity of material throughout the size range of interest for human inhalation and to connect that information with published epidemiologic data. To span the size range of interest it was necessary to use several instruments with overlapping ranges and various means of collecting and sizing the particles. At the smallest size an electrical mobility analyzer coupled with a condensation nuclei counter was used for particle counting. The lower limit of this instrument was 0.01 microm and the upper limit was 0.40 microm. Overlapping this was a low-pressure impactor with a range of 10 microm down to 0.08 microm. The impactor allowed determination of the particle mass as well as beryllium content of the collected material. Personal impactors were also used to compare area samples collected with the two previous instruments with personal measurements made on workers. Samples were taken involving processes that generated sizes, including fumes and coarse particles. The processes involved various chemical forms of beryllium both as a ceramic and alloy. Those processes established as most hazardous for disease had the highest submicrometer fraction of material. Particle count was subsequently highest in those areas as well.
Exposure-assessment; Exposure-levels; Beryllium-compounds; Measurement-equipment; Analytical-instruments; Analytical-methods; Particle-counters; Particulates; Epidemiology; Aerosol-particles; Aerosols; Inhalants; Particulate-sampling-methods; Ceramic-materials; Beryllium-disease; Sampling-equipment; Sampling-methods; Chemical-composition
American Industrial Hygiene Conference and Exposition, May 20-25, 2000, Orlando, Florida