Sampling efficiencies of two modified viable cascade impactors

Abstract

ABSTRACTPrevention of airborne contagious diseases depends on successful characterization of aerosols in the environment. The use of cascade impactors to characterize ambient aerosols is one of the most commonly used methods, providing data on both particle size and concentration. In this study, the use of a cascade impactor recently described in the literature using 8 mL of liquid in Petri dishes (CI-L) was compared with a new method that uses wet membrane filters on top of wax filled Petri dishes (CI-WWMF). Sampling efficiencies of the cascade impactors were evaluated using 0.5, 1, 3, and 5 μm polystyrene latex (PSL) microspheres and aerosol consisting of single spores of Bacillus atrophaeus var. globigii (BG). The sampling efficiency of the CI-L was 6%, 11%, 17%, 21%, and 58% for 0.5, 1, 3, 5 μm PSL microspheres and BG spores, respectively. Higher overall sampling efficiencies of 71%, 91%, 60%, 64%, and 104% were observed for the same size and type of particles for the CI-WWMF. This study indicates tha...