Performance analysis of air purification-enhanced air curtains in particle transport mitigation at building entrances

This study proposes an air curtain system integrated with air purification functionality to enhance the reduction of indoor infiltration of ambient PM_2.5 at building main entrances. CFD simulations on airflow and particle transport were conducted, and a field experiment was carried out for validation of the simulation. Results showed that air curtains effectively minimized particle ingress under low-pressure conditions (e.g., 5 Pa) but showed reduced performance under high-pressure differentials (e.g., 25 Pa). Filter integration significantly enhanced particle reduction efficiency, particularly in low-pressure environments, though its effect diminished at higher pressure differentials. Among various configurations, the dual-side vertical (counter-flow) system demonstrated the highest resilience, maintaining superior airflow sealing and particle blocking efficiency. Architectural factors such as door width and airflow path orientation strongly influenced air curtain effectiveness, with wider doorways and diagonal airflow paths reducing performance. This study can enhances the understanding of outdoor particle ingress at building entrances and contributes to the design of air curtain systems to reduce the particle ingress.