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Deposition of Respirable Dust in an Airway.

Courtney-WG; Cheng-L; Divers-EF
MISSING :10 pages
Because of the inherent safety problem associated with the deposition of airborne respirable dust onto the floor and other airway surfaces, the Bureau of Mines investigated the rate of reduction of airborne respirable dust in an airway due to deposition of the particles onto the surfaces of the airway. The effects of relative humidity and air velocity on the deposition rate were examined. It was found that the deposition rate was comparable in magnitude with the stokes sedimentation rate and that it was independent of relative humidity. However, near the dust source the deposition rate depended significantly upon the air velocity with such dependence decreasing with increasing distance from the dust source. In addition, the size distribution of the airborne particles was approximately constant along the first 300 ft of the airway, indicating that it was not merely the larger (heavier) particles that were being deposited. These results suggest that deposition, though comparable with the stokes sedimentation rate in magnitude, does not follow a simple stokes-type process, and that the process of deposition remains to be explained.
Publication Date
Document Type
IH; Report of Investigations
Fiscal Year
Identifying No.
RI 9041
NIOSH Division
Source Name
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division