Rapid In-Air Inactivation of Influenza A Virus Using an In-Duct Cold Atmospheric Plasma Panel

Abstract

Respiratory virus infections pose a major public health burden and pandemic risk, especially when they are transmissible via the air. Consequently, there is an urgent need for effective control measures to mitigate airborne transmission. Cold atmospheric plasma (CAP) offers a promising solution for in-air virus inactivation by exposing viruses to a mixture of electrons, ions, photons, and reactive oxygen and nitrogen species (RONS). Here, a grating dielectric barrier discharge (DBD) panel consisting of 88 glass-covered electrodes was developed. Plasma formation using a high-voltage neon transformer was confirmed across all electrodes, with a power deposition of approximately 5 W. In an open acrylic tube, representative of an air duct, ozone levels increased to a maximum of 90 ppm and returned to zero within 30 s after the DBD panel was turned off. The obstructing area of the electrodes was 13%, resulting in a lower pressure drop than the current standard HEPA filters. The DBD panel was further tested in an aerosol chamber where the viability of artificially aerosolized influenza A virus (IAV) after a single passage through the DBD panel was assessed. Plaque assays showed that virus inactivation increased with exposure time, reaching 96.9% inactivation after 15 s of exposure and up to 99.9% inactivation when aerosolization followed prior RONS accumulation, whereas RNA levels and air temperature remained largely unaffected. These results demonstrate that in-duct DBD panels can effectively inactivate IAV in aerosols without leaving persistent toxic residues. This proof-of-concept study might give future directions for implementation of CAP technology in high-risk settings such as hospitals, livestock facilities, and transportation hubs to reduce the spread of infectious virus in the environment.