Positive or negative? The pressure control impact in hybrid ventilated hospitals

The outbreak of coronavirus disease 2019 (COVID-19) has had a significant impact on human life. Hybrid ventilated hospitals have emerged as multi-zone sites, necessitating ventilation strategies to mitigate viral concentration. This paper integrates multi-zone infiltration and exfiltration (MIX) model of natural ventilation, spatial flow impact factor (SFIF) model and pollutant concentration model to analyze the inter-zonal impact. Results indicate that elevated outdoor temperature corresponds to an increased influence of rooms on corridors. Adopting mechanical ventilation in rooms diminishes the influence of room pollutants on corridors but exerts minimal impact on other rooms. Mechanical air supply reduces the interaction between corridors, and the reduction is most significant when wind direction is the same as stairwell orientation. The corridors do not affect the upstream rooms when the source is in the corridor. When wind speed is below a threshold, mechanical air supply is recommended; for wind speed reaching this threshold, mechanical air exhaust volumes should be adjusted regarding the wind speed. The study reveals that corridor and room window openings exert disparate effects on corridor concentration under mechanical air supply conditions. All the findings offer valuable insights for selecting ventilation strategies in hybrid ventilated hospitals, with the aim of mitigating COVID-19 transmission.