The aim of the proposed project is to provide an improved scientific framework for developing new samplers suitable for use in the health- related measurement of workplace aerosols. New particle size-selective criteria, which are expected to form the basis of new industrial hygiene standards, are stimulating a critical examination of samplers, currently in use (in the light of those criteria) and the development of new devices. A major limiting factor in the current apprnach to the development and design of such instruments lies in the lack of sufficient understanding of the actual sampling process itself, in particular of the factors governing the efficiency with which airborne particles are drawn into the sampling device from the ambient air outside. As a result, the development of practical instruments matching desired performance characteristics has so far been largely empirical. The proposed project therefore comprises a scientific enquiry into some of the outstanding relevant scientific questions. The objective will be to generate quantitative working guidelines for the future design of practical particle size-selective sampling devices. The conduct of the work itself will involve laboratory-based experimental research, using techniques which have been established in extensive previous research with which the principal investigator has been associated for the past 15 years. This will be backed up by physical and statistical modeling aimed at enabling the generalization of the scientific knowledge gained towards practical outcomes. The project is particularly timely in view of the current move towards international harmonization on methodology for the assessment of worker exposures to aerosols.
