Figure 2.

Aerosol chamber schematic. The test system consisted of a cylindrical 67.5-L polycarbonate chamber supplied with room temperature humidity controlled air. Aerosol generation used an air assist nozzle attached to the top of the chamber that produced aerosol with an initial VMD of 6.3 μm and a GSD of 1.5. The generated aerosols were sampled from ports located at the distal end of the chamber using two 25-mm PTFE filters and an aerodynamic particle sizer (APS), all flowing at 5 L/min. The final equilibrated particle size distribution measured by the APS had an MMAD of 1.3–1.5 μm and a GSD of 1.5–1.6. An additional 40 L/min of exhaust flow was pulled from a separate HEPA-filtered port, resulting in a total exhaust flow of 55 L/min.