Effects of the nozzle-to-nozzle distance on the performance of the water condensation growth-based virus aerosol concentrator

Abstract

Efficient collection of airborne viruses is crucial for monitoring and preventing the spread of respiratory diseases. The laminar flow water condensation-based growth tube collector (GTC) is a microbial sampler extensively used to collect virus aerosol particles owing to its high recovery of viable viruses. The GTC involves multiple nozzles and eight tubes for sampling flow rates of 6–8 L per minute (LPM). To allow the GTC to operate at a higher flow rate, optimizing GTC performance through investigation of the effects of nozzle-to-nozzle distance is essential. Herein, we examined these effects on the collection efficiency and viability of airborne MS2 viruses collected by the growth-based virus aerosol concentrator (GVC), which is a lab-made single-tubed GTC, at flow rates of up to 6 LPM per tube. The flow interactions between adjacent jets were analyzed by observing the particle deposition patterns. The collection efficiencies of MS2 virus aerosol particles and the enrichment ratio of the GVC increased with increasing nozzle-to-nozzle distance. The infectious virus concentration relative to that in the virus suspension (RIVC) ranged from 0.0093 to 0.095 for 5 min of sampling. At flow rates of 1 and 6 LPM, the RIVC decreased as the nozzle-to-nozzle distance decreased, which may be ascribed to the higher shear stress at shorter nozzle-to-nozzle distances applied to the viruses collected through the cross-flows driven by adjacent jets. These measured RIVC values are much larger than those collected by the BioSampler. These findings can provide important insights into optimizing multiple nozzles in high-flow-rate GTCs.