Aerodynamic performance of a ventilation system for droplet control by coughing in a hospital isolation ward

Over 766 million people have been infected by coronavirus disease 2019 (COVID-19) in the past 3 years, resulting in 7 million deaths. The virus is primarily transmitted through droplets or aerosols produced by coughing, sneezing, and talking. A full-scale isolation ward in Wuhan Pulmonary Hospital is modeled in this work, and water droplet diffusion is simulated using computational fluid dynamics (CFD). In an isolation ward, a local exhaust ventilation system is intended to avoid cross-infection. The existence of a local exhaust system increases turbulent movement, leading to a complete breakup of the droplet cluster and improved droplet dispersion inside the ward. When the outlet negative pressure is 4.5 Pa, the number of moving droplets in the ward decreases by approximately 30% compared to the original ward. The local exhaust system could minimize the number of droplets evaporated in the ward; however, the formation of aerosols cannot be avoided. Furthermore, 60.83%, 62.04%, 61.03%, 60.22%, 62.97%, and 61.52% of droplets produced through coughing reached patients in six different scenarios. However, the local exhaust ventilation system has no apparent influence on the control of surface contamination. In this study, several suggestions with regards to the optimization of ventilation in wards and scientific evidence are provided to ensure the air quality of hospital isolation wards.

Automated summary

In this study, a full-scale isolation ward in Wuhan Pulmonary Hospital was modeled and computational fluid dynamics (CFD) were used to simulate water droplet diffusion. It was found that the number of moving droplets in the ward decreased by approximately 30% when the outlet negative pressure was 4.5 Pa. The local exhaust ventilation system could minimize droplet evaporation but could not prevent the formation of aerosols. Furthermore, 60.83% to 62.97% of droplets produced through coughing reached patients in different scenarios. However, the local exhaust ventilation system had no apparent influence on surface contamination control.