Field testing of a personal size-selective bioaerosol sampler

Existing samplers for the collection of bioaerosols have been designed with the aim of maintaining biological stability of the collected material, and in general do not select particles in accordance with international conventions for aerosol sampling. Many have uncharacterised sampling efficiencies and few are designed as personal samplers. If standard personal dust samplers are used for bioaerosols the viability of collected microorganisms may be compromised by dehydration. The objective of this study was to evaluate a novel personal bioaerosol sampler designed to collect the inhalable dust fraction and further subdivide the sample into thoracic and respirable fractions. The new sampler was tested to see whether it enhanced the survival of the collected microorganisms, and was assessed for ease of use in the field and in subsequent laboratory analyses. A number of occupation-related field sites were selected where large concentrations of bioaerosols were to be expected. The prototype sampler was found to be simple to use. Analysis could be carried out with similar efficiency either with all three fractions together for a total count, or separately for size selective data. The sampler performed at least as well as the standard IOM filter method but with the added advantage of size fractionation. The field trials showed that for sampling periods lasting several hours, microorganism survival within the sampler was adequate for culture and identification of the organisms present. This new sampler is now commercially available. In addition to bioaerosol sampling, the principle of size selective sampling using porous foams can be applied to other occupational hygiene problems, and also to indoor air monitoring of PM10 and PM2.5 concentrations.