Respirable Aerosol Sampler Performance Testing

Abstract

Performance tests for evaluating respirable aerosol sampling methods were developed. The tests entail measurement of the flow-dependent collection efficiency of the aerosol size-discriminating part of the sampler using an aerodynamic particle sizer. The bias relative to an international sampler standard adopted by the American Conference of Governmental Industrial Hygienists, the International Standards Organization, and the Comité Européen de Normalisation is mapped over aerosol size distributions of intended application. Imprecision from flow-effects, filter weighing errors, and intersampler variability is either measured or estimated. Uncertainty in the evaluation experiment itself is explained. Samplers can be rejected if, at specified confidence in the evaluation testing, accuracy is lacking in too large a fraction of samples. Alternatively, the data permit specifying a value of the inaccuracy. Two commercially available personal samplers were subjected to the performance tests suggested. The result was the specification of the flowrates at which the samplers closely match the international definition. Furthermore, upper limits on the inaccuracy at which a sampler can be expected to operate were determined. The effect of the acceptance of such performance criteria rather than sampler design specification for compliance sampling would be to encourage the use of accurate samplers and, thus, the development of improved samplers.