Performance of airflow distance from personalized ventilation on personal exposure to airborne droplets from different orientations

Abstract

This study investigated the effect of airflow distance from a personalized ventilation (PV) system on the personal exposure of a PV user to exhaled droplets from different orientations. Constant and dynamic airflow from the PV system was studied. A PV system was designed to produce both constant and dynamic airflows with different periods. Thermal manikins were used to simulate a healthy person (HP), also the PV user, influenced by a respiratory activity from an infected person (IP) at different orientations. Results show that, with a short distance of 0.2 m between the PV and the HP, both constant and dynamic PV flow can effectively protect the HP at all orientations considered; with a longer distance of 0.5 m between the PV and the HP, at some orientations, neither constant PV flow nor dynamic PV flow could protect the HP from the IP under our testing conditions. PV is a potential method to prevent disease transmission. However, a proper design is essential, and the relative position of the PV terminal, the IP and the HP and the distance of the PV from the HP are important factors to be considered so as to achieve the best performance.