EXPERIMENTAL-DETERMINATION OF SIZING PARAMETERS AND WALL LOSSES OF 5 SOURCE-TEST CASCADE IMPACTORS

A calibration study of five source-test cascade impactors has been conducted to determine sizing parameters and wall losses. A vibrating orifice aerosol generator was used to produce monodisperse ammonium fluorescein aerosol particles 18 to 1 µm in diameter. A pressurized Collison nebulizer system was used to disperse polystyrene latex (PSL) spheres 2 to 0.46 µm in diameter. Results are reported showing stage collection efficiencies vs. the square root of the inertial impaction parameter, ѱ, and impactor wall losses vs. particle size. It has been determined that the values of the inertial impaction parameter for 50% collection efficiency are not generally the same for each impactor stage. Published theories do not successfully predict these √ѱ50 values, so empirical calibration is required before these devices can be accurately used in the field or laboratory. © 1979, American Chemical Society. All rights reserved.