Long-term viable bioaerosol sampling using a temperature- and humidity-controlled filtration apparatus, a laboratory investigation using culturable E. coli.

Abstract

ABSTRACTSampling 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 h). 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-min challenge of bioaerosol followed b...