Use of portable air purifiers to reduce aerosols in hospital settings and cut down the clinical backlog

• Published in: Epidemiology and infection 2023-01, Vol.151, p.e21, Article e21
• Main Authors: Salmonsmith, Jacob, Ducci, Andrea, Balachandran, Ramanarayanan, Guo, Liwei, Torii, Ryo, Houlihan, Catherine, Epstein, Ruth, Rubin, John, Tiwari, Manish K., Lovat, Laurence B.
• Format: Article
• Language: English
• Subjects: Aerosols; Air cleaners; Air Filters; Air purification; Alternative energy sources; COVID-19; Disease transmission; Emission control equipment; Experiments; Gastroenterology; Health risks; Hospitals; Humans; Indoor environments; Laboratories; Mechanical ventilation; Original Paper; Otolaryngology; Patients; Portability; Respiratory Aerosols and Droplets; SARS-CoV-2; Severe acute respiratory syndrome coronavirus 2; State Medicine; Velocity; Ventilation
• ISSN: 0950-2688; 1469-4409; 1469-4409
• DOI: 10.1017/S0950268823000092

SARS-CoV-2 has severely affected capacity in the National Health Service (NHS), and waiting lists are markedly increasing due to downtime of up to 50 min between patient consultations/procedures, to reduce the risk of infection. Ventilation accelerates this air cleaning, but retroactively installing built-in mechanical ventilation is often cost-prohibitive. We investigated the effect of using portable air cleaners (PAC), a low-energy and low-cost alternative, to reduce the concentration of aerosols in typical patient consultation/procedure environments. The experimental setup consisted of an aerosol generator, which mimicked the subject affected by SARS-CoV-19, and an aerosol detector, representing a subject who could potentially contract SARS-CoV-19. Experiments of aerosol dispersion and clearing were undertaken in situ in a variety of rooms with two different types of PAC in various combinations and positions. Correct use of PAC can reduce the clearance half-life of aerosols by 82% compared to the same indoor-environment without any ventilation, and at a broadly equivalent rate to built-in mechanical ventilation. In addition, the highest level of aerosol concentration measured when using PAC remains at least 46% lower than that when no mitigation is used, even if the PAC's operation is impeded due to placement under a table. The use of PAC leads to significant reductions in the level of aerosol concentration, associated with transmission of droplet-based airborne diseases. This could enable NHS departments to reduce the downtime between consultations/procedures