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Aerodynamics and Exposure Variability.
Department of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, North Carolina 1990 Feb:12 pages
Exposure levels and how orientation of the body with respect to air flow direction affect mean exposure were investigated in wind tunnel studies with a mannequin and sulfur-hexafluoride as a tracer gas. The mannequin was 41 inches high, and air velocities of 49, 152 and 265 feet per minute were used. Using a point source of tracer gas indicated that locating a contaminant source within a separated boundary layer results in greater exposure variability than when the source is outside such a region. These results provide information for estimating the relative exposure variability between processes under different aerodynamic conditions. While these findings focus on worker position as the generator of such a separated region, such examples will occur in any instance where there is relative motion between the air and a bluff body. Work occurring in large recirculating eddies formed by air movement around machines, or internal walls and boundaries will likely result in greater exposure variability when the pollutant source is within such a zone. The number of measurements needed to evaluate exposure is likely to be greater for such situations. This should serve as a crude guide to help industrial hygienists identify situations of high exposure variability on a relative basis.
NIOSH-Grant; Control-technology; Air-flow; Fluid-mechanics; Work-environment; Ventilation-systems; Air-contamination;
Environmental Sciences & Engr University of North Carolina Rosenau Hall 201H Chapel Hill, NC 27514
Final Grant Report;
NTIS Accession No.
Control Technology and Personal Protective Equipment; Research Tools and Approaches; Control-technology;
Department of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, North Carolina
University of North Carolina Chapel Hill, Chapel Hill, North Carolina
Page last reviewed: April 12, 2019
Content source: National Institute for Occupational Safety and Health Education and Information Division