Sampling efficiencies of personal particulate samplers, terminal progress report.
University of Cincinnati, Cincinnati Ohio, 1981 Nov; :1-3
A newly designed inlet for a particulate air sampler was developed. The inlet was integrated into a modified optical single particle counter that recorded the aerosol concentration penetrating through the inlet. The efficiency of a 20 centimeter long thin walled sampling tube incorporating the inlet was evaluated in a wind tunnel. The device was tested at wind velocities of 250 to 1000 centimeters per second (cm/s) and inlet velocities of 125 to 1000cm/s, oriented at angles of 0 to 90 degrees to the air flow. Efficiency was significantly reduced when sampling was performed at an angle to the flow. When the sampling velocity in the inlet differed from the ambient wind velocity, sampling efficiency was significantly increased. For particles larger than 10 micrometers in diameter, sampling efficiency was affected by small angles. Orienting the inlet upwind at an angle of 15 degrees reduced efficiency, whereas downwind sampling at an angle of 15 degrees increased efficiency. For angles of 30 to 90 degrees, the sampling efficiency was a function of the Stokes number and the ratio of wind velocity to inlet velocity.
NIOSH-Grant; Air-samplers; Measurement-equipment; Dust-particles; Employee-exposure; Exposure-levels; Airborne-particles; Analytical-instruments; Equipment-design
Final Grant Report
NTIS Accession No.
University of Cincinnati, Cincinnati Ohio
Environmental Health University of Cincinnati 3223 Eden Avenue Cincinnati, Ohio 45267