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 μg/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 μm 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 μg/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.