Bioaerosol risk assessment of air curtain ventilation in isolation wards based on static and dynamic scenarios

Due to high concentrations of virus-carrying bioaerosols, the healthcare worker (HCW) faces a high risk of infection in isolation wards. Air curtain ventilation (ACV) has the potential to reduce the infection risk in healthy people. This work studied the effect of ACV on the diffusion of bioaerosols released when the patient was speaking. Combined with the improved Lagrangian-based Wells-Riley model and numerical simulation, the infection risk of HCWs was quantitatively predicted. The results show that the ACV mode performed better in bioaerosol removal and HCW protection than the original downward ventilation mode. Under the same ventilation conditions, both the suspended bioaerosol concentration and HCW infection risk were higher for the sitting case than for the lying case. For the same ventilation rate, increasing the supply velocity was more effective in reducing risk than increasing the air curtain width. The HCW infection risk decreased to 2.34 × 10^-7, when the velocity and width were 1.34 m/s and 0.1 m, respectively. The ACV with a larger length-to-width ratio improved bioaerosol removal and infection risk reduction. Bioaerosol concentrations and infection risk were slightly higher in the dynamic scenario than in the static scenario, but no significant difference was observed. This work can provide a reference for the design and application of ACV in isolation wards.