The sampling efficiency of personal inhalable aerosol samplers in low air movement environments

Experimental systems were developed in two laboratories for measuring the s ampling efficiency of personal inhalable aerosol samplers in low aii moveme nt environments, using sedimenting aerosols. The sampling efficiencies of f our types of personal inhalable or total dust sampler were measured; the sa mplers chosen were the IOM sampler, the GSP conical inhalable sampler, the UK seven-hole sampler and the 37 mm closed face sampling cassette. Isolated samplers or manikin mounted samplers were slowly rotated in an aerosol cha mber, whilst mounted in orientations similar to those in which they are nor mally used for personal sampling. Measurements were made using nine alumini um oxide test aerosols with aerodynamic diameter values ranging from 6 to 9 0 mu m. Reference concentrations in the aerosol chamber were measured using slowly circling sharp-edged probes with matched forward and aspiration vel ocities, to simulate isokinetic sampling. Sampling efficiencies for the IOM , GSP and seven-hole samplers measured using this system were generally hig her than wind tunnel results previously reported at an external wind speed of 0.5 m s(-1) For the 37 mm sampler the results were generally lower than the previous wind tunnel results. Measurements made with the samplers mount ed on the torso of the manikin showed positional differences in sampling ef ficiency, but the average sampling efficiencies were similar whether the sa mplers were on or off the manikin. The experimental system developed in thi s work is simpler and gives more reproducible results than the wind tunnel tests of samplers (mounted on a life-size manikin) that are normally used t o assess personal sampler performance. Crown Copyright (C) 1999 Published b y Elsevier Science Ltd. All rights reserved.