Hotels as quarantine facilities with airborne virus controls

Abstract

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.

Keywords: Air cleaning strategies and devices; COVID-19; Multi-zone modeling; Quarantine hotel; Ventilation; Viral aerosol transmission.

Fig. A.1.

Layouts of HEPA air cleaner deployment scenarios in the common room. The small blue boxes represent the locations of HEPA air cleaners, while the crosses mark the sites selected for noise measurement.

Fig. B.1.

Photos of air cleaning systems.

Fig. B.2.

Developed infiltration models for a door equipped with an air curtain, with and without MERV-13 filter using data from [66]. A positive airflow rate indicates airflow from the room to the corridor. The standard air curtain refers to an air curtain without a filter.

Fig. C.1.

Schematic layout of air cleaning system deployment for different strategies.

Fig. C.1.

Schematic layout of air cleaning system deployment for different strategies.

Fig. 1.

Layout of the quarantine floor.

Fig. 2.

Multi-zone model of the studied floor. The zones labeled C1-C28 represent the individual segments into which the corridor was divided.

Fig. 3.

Daily schedule for the guests.

Fig. 4.

Weather parameter variations for Baltimore (March 1 to March 4) used in simulations.

Fig. 5.

Comparison of noise level and eACH for HEPA air cleaner scenarios for the common room.

Fig. 6.

Comparison of measured and model-calculated data.

Fig. 7.

Impact of applying MERV-13 filtration on air curtain performance. The star denotes index case. The standard air curtain refers to an air curtain without a filter.

Fig. 8.

Zonal distribution of average quanta concentration across the quarantine floor.

Fig. 9.

Maximum steady-state quanta concentration in adjacent rooms for different index case locations in the baseline model.

Fig. 10.

Dynamic variation of NPL at the north wall.

Fig. 11.

24-hour quanta concentration profiles in the index case room and the common room.

Fig. 12.

Reduction in the maximum individual infectious exposure with different air cleaning strategies, along with associated installation cost and energy consumption. Bars represent exposure reduction (left axis); markers represent installation cost and energy consumption (right axes).

Fig. 13.

Average infection risk under various air cleaning strategies.