Field comparison of personal samplers for inhalable dust.

The performances of two designs of personal inhalable fraction sampler, which have been shown to differ in laboratory wind tunnel studies, were assessed in 23 real industrial environments, relative to the collection of dust by a simulated worker. This took the form of a mobile, articulated, breathing robot which was fitted with an oral filter, and could be moved around the workplace to follow and mimic real workers. Statistical analysis of the resulting data show that if a small correction for bias is applied there is no significant difference either between the personal samplers as predictors of the 'real' worker exposure, or in the reproducibility obtained with the two personal samplers. The ratio between dust concentrations measured simultaneously on opposite lapels was greater than 2 on more than 5% of occasions, and is believed to be largely due to real concentration gradients in the environments sampled. It would appear that the differences between sampler performances demonstrated in laboratory studies are not significant under conditions encountered in the field.