Airborne virus collection using the BioSampler at various sampling flow rates and periods under different airborne virus concentrations and collection liquid volumes

Abstract

The SKC BioSampler has been widely utilized as a standard microbial air sampler, and its manufacturer recommends a sampling flow rate of 12.5 L/min. However, the effects of sampling flow rates on the collection of airborne viruses have rarely been studied. In this study, we assessed the collection of airborne MS2 viruses using the SKC BioSampler at various sampling flow rates (4.0, 8.0, 10.0, 12.5, and 13.3 [±0.01] Standard L/min (SLPM); standard conditions: 21.1 C and 101.3 kPa), sampling periods (10, 60, and 360 min), and airborne virus concentrations (10^8,10^6 , and 10^4 PFU/m3) in 20-mL collection liquid. The concentrations of infectious viruses in the collected samples and collection efficiencies for MS2 viruses increased with the sampling flow rate at 10- and 60-min sampling periods, except at the lowest airborne virus concentration. Moreover, a sampling flow rate of 13.3 SLPM was the most efficient for collecting airborne viable MS2 viruses. At 104 PFU/m3 of air, close to the field-level concentrations of respiratory viruses, viable MS2 viruses were detected at 10.0–13.3 SLPM during 360-min sampling. The gene copy concentrations and collection efficiencies for influenza viruses were also measured using RT-qPCR at various sampling flow rates (10.0–13.3 SLPM), and at two concentrations (10^6 and 10^5 gene copies/m3 of air) and collection liquid volumes (20 mL and 13 mL). Similar to MS2 viruses, 13.3 SLPM was the most efficient for collecting the nucleic acids of influenza viruses.