The Effect of the Isolation Hotel Facade Attachment on the Inter-Flat Transmission of Aerosols

Although natural ventilation can effectively control the indoor air quality and thermal comfort, the single-sided natural ventilation in isolation hotels may lead to the transmission of virus-laden aerosols between windows on the same façade but on different floors near the pollution source. Hereinafter, this kind of transmission is referred to as inter-flat transmission. The configuration of the building façade is a key factor influencing this risk. This study took into account various façade attachment scenarios including flat façades (with no attachments), outdoor units only, awnings only, and a combination of outdoor units and awnings. A model based on a real isolation hotel was developed, and computational fluid dynamics (CFD) simulations were carried out to investigate the inter-flat transmission of aerosols under these façade conditions. The study analyzed the risk of gaseous pollutant transmission caused by single-sided natural ventilation and quantified the effects of different outdoor wind speeds and indoor–outdoor temperature differences on this transmission route. When the indoor–outdoor temperature difference was 5 °C, the mass fraction of gaseous pollutants in the receptor rooms above the source first increased and then decreased as the outdoor wind speed increased, reaching a peak at 1 m/s. When the outdoor wind speed was 2 m/s, the mass fraction of pollutants in the receptor rooms increased with the increase in the indoor–outdoor temperature difference. Compared with the flat façade, the presence of outdoor units reduced the air exchange rate of natural ventilation, resulting in a slight increase in the infection risk. A 1 m-long awning reduced the infection risk associated with inter-flat transmission by 46%. Buildings equipped with both a 1 m-long awning and outdoor units achieved a 68% reduction in infection risk. These findings provide valuable insights for mitigating inter-flat transmission and inform the development of relevant policies.

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