Virucidal, bactericidal, and sporicidal multilevel antimicrobial HEPA-ClO2 filter for air disinfection in a palliative care facility

Abstract

• HEPA-ClO 2 with contact-killing and release-killing properties against microbes. • HEPA-ClO 2 with effective in filtering and killing viruses, bacteria, and spores. • HEPA-ClO 2 is safe according to in-vitro and in-vivo studies. • HEPA-ClO 2 is more efficient than unmodified HEPA in field trial and CFD studies. Pathogenic microbes in the air are the leading cause of respiratory diseases and illnesses, and respiratory viruses are responsible for some of the world’s most devastating epidemics and pandemics. Therefore, their capture, removal, and disinfection are essential in preventing the spread of diseases. A multilevel antimicrobial HEPA-ClO 2 prepared by coating micro-encapsulated chlorine dioxide on high-efficiency particulate air (HEPA-H13) filter, displays broad-spectrum virucidal and bactericidal, as well as sporicidal activities through the combined “contact-killing” and “release-killing” properties. In-vitro cytotoxicity (i.e., human A549 cells) and in-vivo inhalation toxicity tests (i.e., Kunming mice) indicate HEPA-ClO 2 has low inhalation toxicity and is safe. Furthermore, it has superb performance against a panel of infectious respiratory viruses (e.g., influenza viruses, EV-71) and bacteria (e.g., L. pneumophila , K. pneumonia ) and drug-resistant organisms (e.g., MRSA, MRPA), attaining log 2 reduction (99%) within a minute. However, spores required 30 min to reach 99% inactivation. A 260-day field trial study at a palliative care facility demonstrated that air purifiers could significantly decrease airborne particulates and microbes (bacteria and mold/fungi) and confirmed the long-term efficacy of the HEPA-ClO 2 filters and their superiority over uncoated HEPA-H13 against microbes. The experimental results from the wardroom were validated by a computational fluid dynamics (CFD) simulation.