SARS-CoV-2 Aerosol Susceptibility to Bipolar Ion Disinfection

Following the onset of the COVID-19 pandemic, bipolar ionization (BPI) emerged as a widely implemented technology that purports to reduce human exposure to airborne pathogens. Though BPI has been deployed for bulk-air disinfection to interrupt disease transmission within congregate settings, limited data is present in the peer-reviewed literature to examine the efficacy of bipolar ions to reduce airborne concentrations of infectious enveloped viruses. This study characterizes the effectiveness of BPI to facilitate inactivation and deposition of SARS-CoV-2 aerosols as a function of bipolar ion concentration and develops dose–response relationships for airborne viral decay. While BPI promoted enhanced airborne SARS-CoV-2 inactivation and depositional loss rates at high concentrations (>105 ions cm–3) of bipolar ions, scaling for a small room with realistically attainable ion concentrations (103 ions cm–3) yields an equivalent air exchange rate of less than 0.1 h–1 for airborne SARS-CoV-2, resulting in limited pathogen reduction under ion concentrations that have been reported during full-room applications. The results presented give context to large chamber and full-room studies that observed no additional bioaerosol decay during BPI conditions and enable the scaling of enveloped viral aerosol decay rates under varying ion concentrations and room volumes to assess the application of BPI technology.