Improved measurement of airborne viruses using a two-stage highly virus-enriching electrostatic particle concentrator...

High enrichment of airborne viruses during sampling is critical for their rapid measurement and requires a high sampling flow rate (or velocity), small collection areas, and high collection efficiency; however, high collection efficiency can rarely be achieved at high flow velocities and in small collection areas in electrostatic sampling. Herein, we present improved measurement of airborne viruses using a two-stage highly virus-enriching electrostatic particle concentrator (HEPC) with wire electrodes and high values of the-inlet-velocity-to-collection-electrode-width ratio. This sampler was evaluated using MS2 viruses and 0.05-2.0 µm diameter polystyrene latex particles at 20 liters/min. Computer simulations and experiments agreed well, showing that the wire electrodes increased collection efficiency (by up to 37 % than the without-wire-electrodes case) without high viability losses through local electric field enhancement for high-flow-velocity regions over the collection electrode and minimization of local corona discharge. The relative infectious virus concentrations of the HEPC were 41-70 times higher than those of the BioSampler. Airborne influenza A viruses at field-level concentrations (1.8 × 10⁵ and 2.6 × 10⁴ copies/m³) were also detected at 10-min sampling due to the high enrichment capability of HEPC. The HEPC has strong potential as a rapid airborne virus monitoring system in the field.