Efficacy of flow-through air purification device in removing aerosolized SARS-CoV-2

Abstract

The COVID-19 pandemic, attributed to the highly infectious nature of the SARS-CoV-2 virus, has prompted the exigent need for the development and evaluation of effective countermeasures. Previous studies have found that antimicrobial technology and increased ventilation can dilute virus concentration in the air or destroy SARS-CoV-2 on indoor surfaces, reducing the risk of spreading COVID-19. However, evidence showing the efficacy of air purifiers equipped with high-efficiency filters in the direct removal of aerosolized SARS-CoV-2 is limited. To plug this research gap, a study was pursued in which aerosolized virology testing was conducted to evaluate the efficacy of a flow-through air purification device in removing aerosolized SARS-CoV-2 (Delta variant). The device was equipped with an internal fan, a high-efficiency particulate air (HEPA) filter, UVC-LEDs, and an ionizer for multipass large-volume air recirculation. TCID50 assays were conducted to quantify and compare the infectious SARS-CoV-2 with and without the operation of the device. It was found that the air purifier was highly effective in removing aerosolized SARS-CoV-2 virus, achieving over four-log reduction within 36 s of operation and under 10 equivalent air changes in the test chamber. These findings suggest that the tested air purifier is a useful countermeasure against the spread of COVID-19 in enclosed spaces. Further research is warranted to evaluate the efficacy of air purifiers in real-world indoor environments to ascertain the wider implications of using such purifiers in safeguarding public health against COVID-19.