Abstract
Two test systems for evaluating dustiness, the Stauber-Heubach (S-H) device and the laboratory dust disperser (LDD), were compared by using two different materials at airflow rates of 4, 10, 25, 50, and 75 L/min. With both devices, the dustiness index for each material increased with airflow rate. Flow rate is an important variable for dustiness tests and should be carefully controlled. Dustiness rankings for the two test materials were related to the test system used. Particle size measurements were also made to enable calculation of an inhalable dustiness index (dust levels associated with particles ≤ 15 µm). The inhalable dustiness index correlated well with the dustiness index for the LDD but not for the S-H. Caution should be used in the interpretation of laboratory dustiness tests; no one instrument or flow rate can absolutely predict dust generation in commercial settings. Dust testing systems provide a relative dust evaluation that may translate qualitatively but not quantitatively to other dust-generating systems. When there is concern for human inhalation exposure, particle size measurements should be incorporated into dustiness tests so that an estimate of “inhalable” dust may be attempted.