Airborne virus capture and inactivation by an electrostatic particle collector

Airborne virus capture and inactivation were studied in an electrostatic precipitator (ESP) at applied voltages from -10 to +10 kV using aerosolized bacteriophages T3 and MS2. For each charging scenario, samples were collected from the effluent air stream and assayed for viable phages using plaque assays and for nucleic acids using quantitative polymerase chain reaction (qPCR) assays. At higher applied voltages, more virus particles were captured from air with maximum log reductions of 6.8 and 6.3 for the plaque assay and 4.2 and 3.5 for the qPCR assay at -10 kV for T3 and MS2, respectively. Beyond corona inception (i.e., at applied voltages of -10, -8, +8, and +10 kV), log reduction values obtained with the plaque assay were much higher compared to those of the qPCR assay because nonviable particles, while present in the effluent were unaccounted for in the plaque assay. Comparisons of these assays showed that in-flight inactivation (i.e., inactivation without capture) was greater for the highest applied voltages with a log inactivation of 2.6 for both phages at -10 kV. We have demonstrated great potential for virus capture and inactivation via continual ion and reactive species bombardment when conditions in the ESP are enforced to generate a corona discharge.