A Novel Device for Measuring Respirable Dustiness Using Low-Mass Powder Samples

Abstract

Respirable dustiness represents the tendency of a powder to generate respirable airborne dust during handling and therefore indicates the propensity for a powder to become an inhalation hazard. The dustiness of fourteen powders, including ten different nanopowders, was evaluated with the use of a novel low mass dustiness tester (LMDT) designed to minimize the use of the test powder. The aerosol created from 15-mg powder samples falling down a tube were measured with an aerodynamic particle sizer (APS). Particle counts integrated throughout the pulse of aerosol created by the falling powder were used to calculate a respirable dustiness mass fraction (D, mg/kg). An amorphous silicon dioxide nanopowder produced a respirable D of 121.4 mg/kg which was significantly higher than all other powders (p<0.001). Many nanopowders produced D values of that were not significantly different from large-particle powders such as Arizona Road Dust and Bentonite clay. In general, fibrous nanopowders and powders with primary particles > 100 nm are not as dusty as those containing granular, nano-sized primary particles. The method used here, incorporating an APS, represents a deviation from a standard method but resulted in dustiness values comparable to other standard methods.

Dustiness of Fine and Nanoscale Powders

“…O’Shaughnessy et al ., (2012) constructed a small-scale falling powder test and used APS counts to estimate respirable mass for several powders, two of which were also investigated here. They report respirable dustiness values of 45.3 (±8.5) mg kg −1 for Aeroxide P25 fumed TiO 2 and 42.9 (±6.0) for Printex 90 carbon black.…”

A system to assess the stability of airborne nanoparticle agglomerates under aerodynamic shear

“…4. These systems include the standard rotating drum method (Tsai et al, 2009), the continuous drop method (Dahmann & Monz, 2011), the modified rotating drum method (Schneider & Jensen, 2008), and the vortex shaker method (Morgeneyer et al, 2013;Ogura, Sakurai, & Gamo, 2009). Lower and upper concentration limits under different experimental parameters in these studies were identified.…”

“…Recently, a modified rotating drum method based on a downscaled version of EN 15051 was developed, which uses much less powder (6 g) per test (Schneider & Jensen, 2008). Other aerosolization systems which employs relatively lower amount of raw material include the Venturi dustiness testing device (Evans, Turkevich, Roettgers, Deye, & Baron, 2013) and the low-mass dustiness tester that simulates the powder falling process (O'Shaughnessy, Kang, & Ellickson, 2011). The powder quantities used in these two methods are 10 mg and 15 mg.…”

The Effectiveness of Specific Risk Mitigation Techniques Used in the Production and Handling of Manufactured Nanomaterials: A Systematic Review

“…The automated packing machine was not covered completely, but the workers did not have to fully attend to the operation of the machine. We found five papers that measured dustiness [43][44][45][46][47]. However, there was no paper that compared changes in the dustiness of nanomaterials, wetting or surface coating of the nanomaterials.…”

“…However, there was no paper that compared changes in the dustiness of nanomaterials, wetting or surface coating of the nanomaterials. However, three papers suggested that nanomaterials had much higher dustiness than pigment grade (submicron size) materials of the same chemical composition and thus could be subject to suppression controls [43,44,47]. All studies were observational.…”