10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Investigation of Bioaerosol Charge Levels Indoors Using the Rutgers Electrostatic Passive Sampler (REPS)
SYDONIA MANIBUSAN, Gediminas Mainelis, Rutgers, The State University of New Jersey
Abstract Number: 1552 Working Group: Bioaerosols
Abstract Previous studies have demonstrated the Rutgers Electrostatic Passive Sampler (REPS) as a novel and effective method for collecting bioaerosol samplers. REPS uses specially arranged and permanently polarized ferroelectric films to electrostatically attract charged airborne particles and deposit them on a film for easy elution and analysis. The REPS device’s method of electrostatic deposition of bioaerosol particles onto film offered a unique opportunity to study the polarity of bioaerosol particles.
The aim of this study was to determine the effect of seasonality on bioaerosol charge using a direct-plating analysis method. REPS devices were used to sample indoor residential environments during the summer and winter over 48-hour intervals. The devices were collocated with an active bioaerosol sampler, the SAS Super 180 Microbial Sampler (Bioscience International, Inc., Rockville, MD), and passive sampling using agar settling plates. The SAS sampler and settling plates sampled at 6 intervals for 3 minutes and 2 hours, respectively. REPS films with the collected microorganisms were either press-plated or eluted into the water for analysis. The press plate method involved applying one side the film directly onto two identical square Tryptic Soy Agar (TSA) or Malt Extract Agar (MEA) plates for bacteria and fungi, respectively. Both the film position and charge (+ or -) of the pressed film face were recorded for each sample plate. The elution method of the collected microorganisms included vortexing and sonication of the entire REPS sampler into 40mL of autoclaved milli-Q water followed by spreading 100µL of the elution liquid onto TSA and MEA plates. All plates were incubated at room temperature and counted for 5 consecutive days.
Passive sampling using the REPS device found average bioaerosol concentrations of 0.784 CFU/cm2h in the summer and 0.131 CFU/cm2h during winter for study location. Active sampling by SAS 180 yielded average culturable bioaerosol concentrations of 291.9 CFU/m3 of bacteria and 109.1 CFU/m3 fungi during winter. The data from summer months showed that almost 90% of bacteria and fungi were attracted to the positively polarized film face, i.e., they carried a negative charge; no significant difference among bioaerosols due to charge was observed during the winter months. This approach to bioaerosol sampling provides a novel method of observing the different impacts of the season and other factors that may affect the behavior and composition of bioaerosols in indoor environments. The study will be expanded to include additional and more diverse indoor environments.