Aerosol penetration characteristics for disposable respirator facepieces.
Ruuskanen-J; Chen-C; Carpenter-DR; Sherman-A; Willeke-K
J Aerosol Sci 1988 Jan; 19(7):1445-1448
The effect of filter material on particle size distribution was studied in a dummy test, and the effect of leakage on particle size distribution was measured with a human test subject. The test aerosol was produced with an ultrasonic atomizing nozzle device from undiluted corn-oil. Penetration measurements of filter material were made by mounting a mask on a filter holder in the chamber and measuring inside and outside concentrations. Measurements were made for six different suction flow rates. The mask was totally sealed in these measurements. In the human study test, the test subject breathed through the nose and sat inside the chamber without moving his head or changing facial expressions. Sampling was then performed in three conditions: the sealed case, in normal use, and in normal use with an artificial leak. In the filter material test, the penetration was influenced by suction flow rate. The results indicated an increase in penetration with increasing suction flow rate. Diffusion was the dominant force in the filtration with interception and sedimentation mechanisms being less important and impaction having only a minor role due to the low velocities used. In studying the different leakage rates, the results indicated that penetration of aerosols varied quite little with leak conditions for particles having physical diameters less than 1 micrometer. In the size range larger than 1 micrometer, the penetration indicated a different size dependent effect between the sealed mask and the mask in normal use. Larger particles were able to enter through facial leaks.
NIOSH-Publication; NIOSH-Grant; Aerosol-particles; Particulate-dust; Air-sampling-equipment; Respiratory-protective-equipment; Personal-protective-equipment; Dust-control; Air-quality-monitoring; Air-sampling-techniques
Environmental Health University of Cincinnati Dept of Environmental Health Cincinnati, Ohio 45267
Journal of Aerosol Science
University of Cincinnati, Cincinnati, Ohio