Decoupled synergistic control of airborne infection risk and thermal comfort in open layout dental clinics: Integration of indoor airflow pattern, physical barrier, and air purifier.

Open layout dental clinics represent a typical medical environment characterized by high bioaerosol exposure risk and stringent thermal comfort requirements. Optimization of conventional air-conditioning airflow patterns often fails to simultaneously control thermal comfort and infection risk. Moreover, existing studies have largely overlooked surface contact infection caused by bioaerosol deposition. This study proposes a decoupled synergistic optimization strategy for indoor thermal comfort and airborne infection risk, based on the integration of airflow pattern, physical barrier and air purifier. First, airflow pattern of HVAC system is optimized to ensure indoor thermal comfort. Subsequently, low-intervention pollution-control devices (physical barriers and air purifiers) are introduced to reduce indoor bioaerosol concentrations and suppress dispersion pathways without compromising thermal comfort. Based on Dose-response model, CFD-based bioaerosol surface deposition model and corresponding contact infection risk assessment method are developed. To overcome the low computational efficiency of traditional Lagrangian particle-tracking approach in air-purifier simulations, an air-purifier performance prediction model is established using Eulerian contaminant transport equation combined with customized parallel computing. Results show that optimal airflow pattern reduces indoor average Predicted Percentage Dissatisfied (PPD) to 8.5%. Under this thermal comfort scenario, the addition of 1.5-meter-high physical barrier or air purifier with output airflow rate of 0.06 m3/s reduces respiratory infection risk to below 0.1% and surface contact infection risk to below 1E-06. Meanwhile, the PPD variation remains within 12%, with slight improvement in overall thermal comfort. This study provides an engineering reference for indoor environmental optimization and infection-risk control in dental clinics and similar healthcare environments.