Performance of a whole-body human dust inhalation challenge exposure chamber

Background: Evaluation of the performance of a whole-body human dust exposure chamber is presented in this report. Methods: The volume of the chamber is 2.13 m(3) and it is operated at a flow rate of 1.0 m(3)/min. Makeup and exhaust air were filtered. A Wright Dust Feeder was used to generate fly ash, the testing agent. An elutriator was used to maintain particles in the respirable range. A Rupprecht and Patashnick PM-10 TEOM, a direct reading instrument, was used to monitor particle concentration. Particle size distributions were determined by a QCM cascade impactor. The evenness of dust concentrations in the chamber was determined gravimetrically. Results: Dust concentrations measured at different points within the chamber were associated with variability less than 10%. Dust concentrations measured by the TEOM, in mu g/m(3), at 0.2, 0.4, 0.8 and 1.6 RPMs of the Wright Dust Feeder, were 110 +/- 2.8, 173 +/- 8.5, 398 +/- 20 and 550 +/- 17, respectively. Particle size distributions (MMD and GSD) were 1.27 mu m and 2.35, 1.39 and 2.22, 1.46 and 2.08, 1.15 and 2.2, respectively. Total dust concentrations measured gravimetrically in mu g/m(3), were 135 +/- 21, 200 +/- 35, 333 +/- 18 and 891 +/- 27, respectively. Conclusion: The whole-body human exposure chamber offers several advantages and has better performance than most of the inhalation challenge systems previously described.