The airflow distribution and aerosol diffusion rules in the negative pressure isolation ward

Negative pressure wards are significant in preventing the spread of infectious pathogens which play a crucial role in fighting against COVID-19. Owing to the negative pressure, contaminated air with pathogens is not able to flow from the wards to non-contaminated zones while fresh filtered air will be transported to the ward via the ventilation system. As airflow controlled by ventilation systems affects the motion of pathogens, for example, infectious aerosol particles, the ability of a negative pressure ward to reduce the risk of infection highly relies on an effective ventilation system. In this investigation, impacts of airflow patterns under various human postures and ventilation processes aerosols diffusion are analyzed via the computational fluid dynamics (CFD) simulation. According to the results, among three airflow patterns, the highest contaminant removal efficiency is 57% at 200 s with the top supply and bottom return mode; besides, in three postures, in the case that the patient is in a standing position, the contaminant removal efficiency is the highest. Furthermore, it is found that the best airflow scheme is a slit tuyere in the ward, with a top supply and side return mode and a sitting position for the patient. This study may provide a reference for the design of airflow in negative pressure isolation wards, control of contaminants, and prevention of viral infections, so as to ensure a good working and recovery environment for medical staff and patients.

Automated summary

Negative pressure wards are important for preventing the spread of infectious pathogens. Effective ventilation systems play a crucial role in reducing the risk of infection by controlling the airflow and motion of pathogens. This study analyzed the impact of airflow patterns and human postures on aerosol diffusion using computational fluid dynamics simulation. The results showed that the highest contaminant removal efficiency was achieved with the top supply and bottom return mode, and the standing posture had the highest efficiency. The study recommended a specific airflow scheme for negative pressure isolation wards to ensure a safe environment for medical staff and patients.