Performance of a prototype of the push-pull type personalized air curtain (PPAC) aimed to reduce respiratory infection risks

We present a prototype of the desktop-mounted push-pull personalized air curtain (PPAC) system. The system comprises a supplying unit and a capturing unit, which together create a lateral air barrier between an infector and an infectee. This air barrier is designed to block, entrain, and capture infectious aerosols generated during respiratory activities in close proximity.

The performance of the PPAC was examined in the office mock-up with a breathing thermal manikin and a heated cylinder, simulating two individuals sitting face-to-face at an 80 cm distance. The room was ventilated using either mixing or displacement ventilation, each supplying 20 L/s of clean outdoor air. A tracer gas was dosed into the exhaled air of the manikin to emulate infectious aerosol, and its concentration was measured at multiple locations to estimate the system's performance. The PPAC was tested at varying distances from the breathing manikin and with different airflow rates, while the manikin exhaled at different flow rates to simulate various aerosol releases.

When the PPAC was used, tracer gas concentration reduced considerably. The estimated capture efficiency reached nearly 60 %, comparable to the performance of some personal protective equipment. Capture efficiency improved with higher PPAC airflow rate and when the system was placed closer to the infector.

Further developments of the PPAC are necessary to understand its performance using actual aerosols. Still, our results show the considerable potential of using this type of solution for reducing infection risks in buildings with mostly sedentary occupants, such as schools and open-plan offices.