Effects of table based air curtains on respiratory aerosol exposure risk mitigation at face-to-face meeting setups.

Face-to-face meetings on a conference table are a frequent form of communication. The short-range exposure risk of aerosol disease transmission is high in the scenario of susceptible facing the infectious person over the table. We propose a mitigation methodology using the air curtain to reduce direct exposure to virus-laden aerosols. A numerical model was validated with experimental data to simulate the dispersion of aerosols. A dynamic mesh was adopted to consider the head movement of a 3D thermal manikin model. Results show that nodding head increase the potential risk by 74 % compared to motionless. Subsequently, for a single air curtain, placing it in the middle of the table is more effective in preventing risks than on the sides. For double air curtains, increasing the distance between them has a greater risk reduction effect than a shorter distance. Increasing the air velocity or width is more effective than increasing the number of air curtains. A moderate velocity (1 m s^-1) works well to reduce the risk of nasal breathing. A higher velocity (2 m s^-1) is needed for the coughing scenario. For similar indoor environments, the air curtains on the table can offer active precautions without changing the current ventilation system.