Particle bounce in a personal cascade impactor: a field evaluation.
Hinds-WC; Liu-CV; Froines-JR
Am Ind Hyg Assoc J 1985 Sep; 46(9):517-523
The effect of particle bounce on the impactor collection surface of a personal cascade impactor was investigated. The impactor was a baffled inlet with eight, six, or four impactor stages followed by a built in filter holder. Each stage had six radial slots with bevelled inlets. The impactor cut points were calibrated for a 2 liter per minute flow rate. Constant flow pumps provided a 3 liter per minute sampling flow rate. Simultaneous parallel samples were taken with five impactors with collection surfaces of plain uncoated stainless steel (USS), grease coated stainless steel (CSS), oil reservoir Millipore membrane filter (OMM), oil reservoir Teflon membrane filter (OTM), and oil reservoir sintered metal (OSM). Lead- dioxide (1309600) generated in a laboratory, brass pouring fume, and brass grinding dust in an automated brass foundry were used as test aerosols. Lead (7439921) content of the particulate deposited on each stage was determined and used to estimate the mass median diameter ratio (MMD). There was no difference between the MMD estimated from using the USS, CSS, or OMM in laboratory generated lead-dioxide. There was a similar trend for the brass pouring fume containing 7 percent lead. USS and CSS collection surfaces gave the same MMD. Aerosol bounce characteristics for samples collected in the laboratory, pouring, and grinding areas were different. CSS substrates had a higher average MMD than that obtained with USS and OMM substrates. OTM and OSM indicated that for grinding dust the CSS worked as well as the oil reservoir Teflon membrane. Bounce occurred with brass grinding dusts on a bare metal surface. Grease coating prevented bounce. The authors conclude that accurate estimates of the size distribution of lead aerosol in brass foundries may be determined using grease coated impaction surfaces. The results underscore the need for field evaluation of impaction surfaces.
NIOSH-Publication; NIOSH-Grant; Grants-other; Quantitative-analysis; Trace-analysis; Dust-exposure; Air-monitoring; Analytical-models; Safety-equipment; Trace-metals; Air-contamination; Analytical-methods; Occupational-exposure
Other Occupational Concerns; Grants-other
American Industrial Hygiene Association Journal