Airborne bioaerosol transmission in hospital waiting corridor: Characteristic, exposure risk and evaluation of prevention strategies

Following the global COVID-19 pandemic, greater attention has been paid to public health safety, especially in hospital environments. In waiting areas with interconnected spaces, complex airflow, unclear bioaerosol dispersion, and the limitations of traditional control methods pose major challenges. This study combined real-world experiments and numerical simulations to investigate the airborne transmission characteristics of pathogen-laden aerosols in a hospital waiting corridor. Serratia marcescens was used as a tracer bacterium to measure bioaerosol concentrations through release experiments. Computational Fluid Dynamics(CFD) has been used to analyze airflow characteristics in hospital corridor by Ω-vortex and air of age, and the improved Wells-Riley model was used to evaluate time-averaged exposure risk and identify high-risk zones under different conditions. The transport of bioaerosols within the waiting corridor is significantly influenced by its interaction with adjacent spaces. For instance, airflow from the main entrance can effectively reduce the overall deposition rate. However, opening the doors to consultation rooms diminishes the effectiveness of this entrance airflow, leading to an 8.14 % increase in the corridor's deposition rate compared to the scenario with only the entrance open. Two control strategies were examined: increasing air changes per hour (ACH) and enhancing exhaust air pressure difference. Both approaches were found to lower mean indoor bioaerosol concentrations. Notably, increasing exhaust air pressure difference to the −3 Pa can reduce the average concentration by up to 35.66 % and lowered deposition across multiple zones (decreasing 9.27 % in all zones). In contrast, raising ACH could worsen local deposition despite reducing airborne concentration because it can also increase deposition rate (10ACH, increasing 6.12 %). The results demonstrate that airflow from adjacent spaces is a significant factor within the hospital waiting corridor and should not be overlooked. Furthermore, in corridors with mechanical ventilation, increasing the exhaust pressure differential is a more effective and practical strategy for bioaerosol control.