Mitigating bioaerosol exposure risks in high-traffic clinics: Experimental and numerical optimization of air purifier...

In outpatient clinics, close contact between doctors and patients increases the infection risk for doctors due to the presence of pathogenic bioaerosols exhaled by patients. Therefore, investigating the bioaerosols dispersion in outpatient clinics and evaluating the intervention effects of air purifiers is of significant practical importance. In this study, employing Serratia marcescens as a tracer to conduct a comparative analysis of the aerosol control effects of air purifiers. Then, numerical simulation is utilized to complement bioaerosol experiments. Analyzed six different placement positions and heights for the air purifiers. The results indicate that air purifiers can effectively reduce aerosol concentrations. The time to reach 95% of the steady-state concentration decreased from about 400 s to 200 s. The peak concentrations being reduced to 25% of those in the original clinic. Placement at breathing height significantly outperformed ground-level placement, achieving "near-source capture." Furthermore, relying solely on spatial average concentrations is insufficient to evaluate the purification effect; incorrect placements may reduce spatial concentrations but primarily increase wall deposition (increased by 13%) rather than actual removal. Additionally, the interference of the purifier exhaust with the original airflow may inadvertently increase the exposure risk for the doctor. Aligning the exhaust of the purifier towards the room's exhaust vent can enhance expulsion efficiency. Considering three dimensions, CPB (Conventional position at breathing height) and SPB (Source capture position at breathing height) emerge as the optimal configurations.