Abstract
This article describes the evaluation of optimal operating modes for three existing respirable dust samplers by computer modeling of their experimentally determined sampling characteristics. The motivation behind this study is the agreement, in principle, to replace the diverse United States, European, and International conventions for respirable dust sampling with a single new convention. In assessing the sampler performance with respect to the new convention, some questions of general importance in the development of performance specifications for dust sampling instruments are discussed.
The three instruments considered in this study were the U.K. SIMPEDS cyclone, the U.S. 10-mm nylon cyclone, and the MRE 113A horizontal elutriator. Although there is a considerable body of experimental data on these instruments, in no case is the complete picture available.
The experimental data were used to computer model the mass that the instruments would sample from a range of ideal lognormally distributed aerosols by numerical integration and to compute the bias in sampled mass compared to an ideal instrument matching a sampling convention exactly. The optimum instrument flow rate and mass correction factor were calculated as those which resulted in the smallest mean bias over a range of aerosol size distributions. The aerosol size distributions considered had aerodynamic mass median diameters between 1-25 μm and geometric standard deviations from 1.5 to 3.5. However, three different methods for choosing or weighting the size distributions within this range were investigated and their effect on the outcome of the sampler optimization were evaluated. Lidén, G.; Kenny, L.C.: Optimization of the Performance of Existing Respirable Dust Samplers. Appl. Occup. Environ. Hyg. 8(4):386-391; 1993.