Quantifying the Impact of Ultraviolet Subtype C in Reducing Airborne Pathogen Transmission and Improving Energy Efficiency in Healthy Buildings: A Kahn–Mariita Equivalent Ventilation Model

• Published in: Frontiers in built environment 2021-10, Vol.7
• Main Authors: Kahn, Kevin, Mariita, Richard M.
• Format: Article
• Language: English
• Subjects: ACH and eACH; air quality; airborne transmission; healthy buildings; UVC disinfection; ventilation
• ISSN: 2297-3362; 2297-3362
• DOI: 10.3389/fbuil.2021.725624

There is growing evidence that viruses responsible for pandemics, such as Middle East respiratory syndrome and severe acute respiratory syndrome, are mainly spread through aerosols. Recommendations have been introduced to reduce the transmission risks of virulent airborne viral particles by increasing ventilation rates, expressed in air changes per hour (ACHs), effectively improving the dilution of pathogens via mechanical ventilation. However, infrastructural and operational costs associated with upgrades of building heating, ventilation, and air conditioning systems make these solutions expensive. It is well documented that Ultraviolet Subtype C (UVC) disinfection can help lower exposure risks by inactivating viruses and the performance of such solutions can translate into equivalent ventilation. Here, we present the first framework to extract the optimal UVC requirements to improve facility management yet ensuring compliance with ventilation guidelines at lower energy costs. The Kahn–Mariita (KM) model considers the air quality of shared enclosed spaces over time by supplementing the existing mechanical ventilation with localized UVC air treatment and includes variables such as room size, occupancy, existing ventilation, and target equivalent ACH. For example, the model applied to a conference room shows that a UVC chamber with recirculation rates of 160 m 3 /h increases ventilation from an ACH 3 to 7.9 and reduces the room’s reset time from 46 to