The development of a rapid testing method for personal aerosol samplers.

Development and characterization of samplers whose performances mimic the inhalability of the human head will be an important step forward in exposure assessment for environmental and occupational aerosols. The current method for sampler characterization involves arduous experiments in large wind tunnels, of which only a few exist. Therefore a new, rapid and cost-effective method is needed. The main objective of this research was to develop a new methodology for aerosol sampler characterization in a small-scale wind tunnel using an aerodynamic particle sizer (APS), which counts and sizes sampled particles. For this purpose, a prototype automated experimental system was designed and built, which included a novel approach to account for particle losses inside the sampler inlet. For this, the sampler entry was filled with a plug of porous plastic foam that smoothed the aspirated air flow and provided well-defined particle penetration into the instrument. The first experiments with this system investigated the aspiration efficiency of a thin-walled probe at 90° to the wind. The results were in fair agreement with previously published data, but indicated some internal functional relationships not previously seen. For the main experimental study aimed at practical aerosol samplers, scaling relationships were developed to describe the way in which full-scale experimental conditions may be simulated by small-scale experiments. A key component is that not only are the sampler dimensions and air flows able to be scaled, but the particle size itself may be scaled as well. This allows for particles in the range of the APS (up to 20 mum) to be used to simulate the behavior of much larger particles. These scaling laws were applied to experiments for testing the performance of three commercially-available personal aerosol samplers, namely: the IOM Personal Inhalable Aerosol Sampler, the CIS Inhalable Aerosol Sampler and the Button Aerosol Sampler. Results from these experiments provided validation of the scaling laws and were broadly consistent with what has been previously observed in large wind tunnels. Again, some additional functional relationships were observed that were not previously seen by others. Despite some differences in sampler performance when compared to full-scale studies, it is concluded that the new testing method developed in this research will be an excellent starting point for the preparation of a standard protocol for the evaluation of practical aerosol samplers.PhDEnvironmental scienceHealth and Environmental SciencesOccupational safetyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/123797/2/3106023.pd