AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Sampling Efficiencies of two Modified Cascade Impactors
JANA KESAVAN, Pamela Humphreys, Daniel Mcgrady, Garrett Nelson, Meera Kesavan, Ana Rule, US Army Edgewood Chemical Biological Center
Abstract Number: 361 Working Group: Health Related Aerosols
Abstract Prevention of airborne contagious diseases depends on successful characterization of aerosols in the environment. Andersen viable cascade impactors have been extensively used to characterize the size and concentration of culturable biological aerosols. Recently, several studies have modified the Andersen cascade impactors to acquire more information than what is provided by traditional use of agar-based impactors. In this study, we evaluated a method recently published that used liquid instead of agar in the Petri dishes (CI-L) and compared it to a method that uses wet membrane filters on top of wax-filled Petri dishes (CI-WWMF) as collection surfaces. Sampling efficiencies of the cascade impactors were evaluated using 0.5, 1, 3, and 5 μm polystyrene latex (PSL) microspheres and single spore Bacillus atrophaeus var. globigii (BG). The sampling efficiency of the CI-L was 5%, 11%, 17%, 21% and 58% for 0.5, 1, 3, 5 μm PSL and BG. Higher overall sampling efficiencies of 76%, 91%, 60%, 64% and 73% were observed for the same size and type of particles for the CI-WWMF. This study indicates that using wet filters on top of wax-filled Petri dishes (CI-WWMF) in a viable cascade impactor is a more efficient method for size-selectively collecting biological aerosols into liquid from the environment and can be used in health care settings to determine the size distribution of bioaerosols.