Abstract
Dust samplers fitted with two types of size selector, the cyclone and the horizontal elutriator, were compared in a wide range of mineral dust clouds. Results indicate that the cyclone size selector (10-mm hydroclone) when operated at 1.4 liters/min gave a “respirable” dust concentration by mass approximately equal to that obtained by using the horizontal elutriator built to the Medical Research Council (United Kingdom) recommendations. This cyclone at this flow rate also gives a “respirable” mass concentration corresponding closely to that obtained by using the Atomic Energy Commission (United States) recommendations.