Hotels as quarantine facilities with airborne virus controls.

During the COVID-19 pandemic, hotels were converted into quarantine facilities, often lacking adequate air-cleaning infrastructure. This study aimed to design effective air-cleaning strategies for controlling viral aerosol transmission, especially inter-zonal transmission, which can undermine the quarantine effectiveness in isolating infected individuals. We developed a validated multi-zone model for an actual quarantine hotel to evaluate performance of air-cleaning strategies. Importantly, we developed the inter-zonal air exchange rate (zACH) index to evaluate the air-cleaning infrastructure effectiveness in reducing inter-zonal transmission of aerosols. The zACH improved significantly from a total of 0.4 1/h of clean air in the baseline strategy without additional air-cleaning to a total of 3.5, 2.8, and 1.7 1/h of clean air for strategies with only GUV fixtures, only HEPA air cleaners, and only air curtains, respectively. We also evaluated the combined air-cleaning strategies that integrated these systems, including air hygiene strategies with fewer devices complementing each other. Our best air hygiene strategy, resulting in the zACH of 8.5 1/h, reduced maximum individual infectious exposure risk below 0.4 % in rooms and below 1.6 % in corridors for a generation rate of 50 quanta/h. Importantly, air-cleaning effectiveness was not linearly proportional to the number of deployed devices, highlighting the importance of balancing performance with installation costs and energy consumption considerations. These findings offer an analytical framework for enhancing infection control in quarantine hotels and provide insights for public health mitigation strategies during pandemics.