Mitigation of Airborne Disease Transmission and Particle Capture by Ceiling Fan Ventilation in Street Stores

Street stores are high-density environments that are regarded as high-risk public spaces during epidemics and influenza outbreaks. The use of ceiling fans (CF) to improve airflow organization is considered an effective strategy for mitigating airborne virus transmission. While CFs offer advantages such as energy efficiency, cost-effectiveness, and ease of implementation, their effectiveness has not been quantitatively described. In this study, tracer gas diffusion experiments combined with computational fluid dynamics (CFD) simulations were conducted to evaluate various CF operation strategies in a representative street store in northern China. Occupant infection risk was further quantified using the Wells-Riley model. Results indicated that in enclosed environments, CFs could provide only short-term reductions in breathing-zone concentrations. When combined with natural ventilation (NV), particle removal efficiency increased by at least 60%. Comparative analysis revealed that low CF speeds were insufficient for particle removal, while excessively high speeds facilitated viral dispersion. Optimal control of overall infection risk was achieved when NV+CF operated at 196 RPM.