Aspiration efficiency of IOM-like personal aerosol samplers from experiments with a new rapid data acquisition system.
Aerosol Sci Tech 2005 Dec; 39(12):1164-1173
New automated instrumentation for the rapid acquisition of aerosol sampler aspiration efficiency data has been applied to an investigation of a range of personal aerosol samplers of the type developed during the 1980s at the Institute of Occupational Medicine (IOM) in Edinburgh, Scotland, U.K. The experimental research was carried out in a small wind tunnel, and the relation of the results for IOM-like samplers to full-scale life-size personal aerosol sampling scenarios-like those encountered in occupational aerosol exposure assessment-was investigated by reference to the scaling laws that have been developed based on familiar aerosol mechanics as they apply to the physics of aerosol sampling. In the small-scale experimental study, the IOM-like sampler was mounted centrally on a rectangular bluff body, simulating the wearing of the sampler on the body (e.g., as by a worker in an industrial setting). Scaling with respect to the corresponding, more-realistic full-scale system for a corresponding full-scale windspeed of 1.0 m/s was achieved by varying the inlet diameter, the windspeed and the sampling flowrate. The results for windspeeds in the scaled experiments of 1.5 m/s and lower were found to differ significantly from those for windspeeds of 2.0 m/s and higher. In particular, the measured aspiration efficiency values for the lower windspeeds were markedly higher than-and clearly not consistent with-the higher windspeed group of results. It is considered likely that such divergence may be associated with a characteristic of the small wind tunnel in which the experiments were conducted. However, the scaling laws developed were found to work well for windspeeds in the scaled experiments of 1.5 m/s and higher. The results confirm that the performance of the IOM personal inhalable aerosol sampler is in quite good general agreement with the inhalability criterion.
Aerosols; Aerosol-particles; Aerosol-sampling; Sampling; Sampling-methods; Samplers; Occupational-exposure; Models
Aerosol Science and Technology
University of Michigan, Ann Arbor, Michigan