AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Long-Term Viable Bioaerosol Sampling Using a Temperature- and Humidity-Controlled Filtration Apparatus
HOWARD WALLS, Jean Kim, Lauren Harvey, Robert Yaga, Laura Haines, David S. Ensor, Susanne Hering, Steven Spielman, Nathan Kreisberg, Research Triangle Institute
Abstract Number: 319 Working Group: Bioaerosols
Abstract Sampling for culturable (e.g. viable) aerosolized microbes (bioaerosols) is a useful means to provide information for public health monitoring and studies. However, it is challenging to maintain microbe culturability when sampling at high flow rates (>12 L/min) and extended periods of time (≥4 hours). We developed a first-generation, viable bioaerosol collection system (VBCS) utilizing temperature (T) and relative humidity (RH)–conditioned filtration at a flow rate of 25 L/min. A two-stage system of tube-in-shell Nafion™ exchange units provides cooling to ≤10°C and RH conditioning to 80–95%. Aerosol particles are collected on a polyurethane nanofiber filter providing a physical collection efficiency of >95% for sizes 0.06–10 µm. The T and RH conditions at the collection filter are maintained, despite changes to ambient conditions. The initial testing of the VBCS was done under indoor, laboratory conditions with aerosolized, vegetative E. coli. A scenario of a 30-minute challenge of bioaerosol followed by continued sampling of clean air for various times was used to judge culturability maintenance under extended-term sampling. An initial, loss of culturability upon collection onto the filter was observed; 23±13% relative to 4-mm all-glass impinger. However once collected, 98% of culturability was maintained for an additional 4.5 hours of sampling. An exponential decay in culturability was observed from 8 hours to 15 hours of sampling. Also, 24-hour cold storage of the filters collected was studied. The VBCS is based on the use of dry filter cassettes, needs minimal maintenance, and preserves culturability of vegetative bacteria for >4 hours.