Abstract
Aerosol generation methods that continuously generate polydisperse nanomaterial particles simulating workplaces handling nanomaterials are required for evaluating nanomaterial exposure and measurement methods. In this study, a vortex shaker method that has been suggested as one of the dustiness test methods was applied, and its performance as a continuous nanomaterial generator was investigated. Nano-TiO2 powder P25, which is widely-used as engineered nanoparticles, was used to verify the performance. The time-series behavior of number concentrations and size distributions of particles were measured by real-time monitoring instruments. The results showed that almost all the nanomaterials were generated as agglomerates with more than 100-nm sizes. In the submicron size range, the profiles of the size distribution were maintained despite the elapsed time of the generation, although the concentrations were changed. By agitating the samples with small beads, the initial concentration and size distribution were maintained. In the micron size range, the initial generation state was maintained for a long period without the beads, while the concentrations were increased when the beads were used. This study proposes that these generation methods are applicable to evaluating the performance of the nanomaterial measurements with real-time particle counters, which require only a small volume of air sample.
