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The effect of aerosol size distribution and measurement method on respirator fit.
Holton PM; Willeke K
Am Ind Hyg Assoc J 1987 Oct; 48(10):855-860
The effect of particle size and detection method on respirator fit tests was investigated. The leakage of aerosol particles through three circular holes 0.57, 1.07, and 1.68 millimeters (mm) in diameter in a negative pressure half face respirator worn by a human subject was measured. The test aerosols consisted of a fine aerosol (a mixture of smoke from burning incense and nebulized corn-oil), corn-oil, and limestone. Leakage of the aerosols through the three holes was determined by measuring particle concentrations for each of 11 particle sizes between 0.07 and 4.4 microns inside and outside the respirator. The fine aerosol particles were counted by an electrostatic aerosol classifier (EAC) and a condensation nucleus counter (CNC). The corn-oil and limestone particle concentrations were measured by an active scattering aerosol spectrometer and an aerodynamic particle sizer. Maximum overall leakage through the holes in the respirator facepiece occurred for particles in the 0.2 to 1.0 micron size range. Maximum leakage through the 1.07 and 1.68mm holes occurred with 0.28 to 0.54 micron sizes particles. Maximum leakage through the 0.57mm hole occurred with 0.50 to 0.98 micron size particles. The CNC measured a smaller leakage than the EAC. The authors conclude that maximum leakage through holes in a respirator facepiece occurs for aerosol particles having sizes 0.2 to 1.0 microns. To obtain a proper fit, the size distribution of the test aerosol and the aerosol that the respirator wearer will be exposed to and the measurement method should be considered.
NIOSH-Publication; NIOSH-Grant; Personal-protective-equipment; Respiratory-protection; Laboratory-techniques; Aerosol-particles; Equipment-reliability; Humans
Environmental Health University of Cincinnati Dept of Environmental Health Cincinnati, Ohio 45267
Issue of Publication
American Industrial Hygiene Association Journal
University of Cincinnati, Cincinnati, Ohio
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division