Impact of Atmospheric Stability on Urban Bioaerosol Dispersion and Infection Risk: Insights from Coupled WRF–CFD Modeling

The rapid pace of global urbanization has exacerbated the urban wind-heat environment, posing a severe threat to public health and sustainable urban development. This study explores the aerodynamic transport characteristics of bioaerosols in a local urban area of Beijing following an accidental bioaerosol release. By coupling the Weather Research and Forecasting (WRF) model with a Computational Fluid Dynamics (CFD) model, the research accounts for the temporality of urban airflow and atmospheric stability. A dose–response model was employed to assess the exposure risks to Beijing Institute of Technology personnel. The findings reveal substantial differences in flow fields and bioaerosol dispersion under varying atmospheric stability: the infection area ratio was 42.19% under unstable conditions and 37.5% under stable conditions. Infection risk was highest near the release source, decreasing with distance. Under the three stability conditions, the probability of infection is highest near the release source and decreases with increasing distance. Contaminants propagate more rapidly under unstable conditions, while stable conditions have a higher concentration of high-risk areas. Gender-based analysis indicated a higher infection probability for males due to elevated inhalation rates. This study elucidates the critical role of atmospheric stability in bioaerosol dispersion and provides a robust scientific foundation for biosafety planning, including early warning, mitigation, and emergency evacuation strategies.