###### Abstract
They concluded that lower penetration velocity of clean air may be used to achieve lower energy consumption with less outdoor clean air. However, they also suggested that airflow disturbances in the breathing zone due to the thermal plume still need careful consideration, depending on the positioning and direction of the nonuniform flow from the nozzle, especially at a lower supply-air velocity. Lobed orifices introduced in the design of mixing ventilation by a perforated panel-ceiling diffuser were found to have better initial spread due to increased induction, without reducing the jet-throw length [39; 40]. The lobed edge of the nozzle generated large streamwise structures known to be responsible for the jet induction phenomenon [41; 42]. The possibility of controlling the characteristics of the inserted jet by introducing a lobed nozzle design was explored in a study by [PERSON] et al. [43]. The inhaled air quality was assessed by the personal exposure effectiveness index (PEE) introduced by [PERSON] et al. [44]. It has been reported that lobed-geometry nozzles have wider initial spread but increased mixing compared to free circular jets or plane jets [42; 45; 46; 47; 48; 49]. For close distances between the lobed nozzles and the face corresponding to the situation considered in this article, initial side spread was considered beneficial because the inserted jet would better cover the mouth and the surroundings of the inhalation zone, resulting in higher PEE. The results, however, did not fully validate this expectation. The lowest PEE obtained was with the four-leafed lobed nozzle. The six-lobed jet performed equally well compared to the circular and elliptical nozzles for distances of 0.04 m and 0.06 m from the mouth and a velocity of 0.4 m/s. If air is diffused in proximity of an occupant's face, the inserted flow should not affect the body's thermal sensation [23]. Local discomfort is likely if the initial velocity is high. Experiments evaluating the performance of a rectangular diffuser incorporated in a headset [32] with an initial velocity of around 1.7 m/s were met with reports of unpleasant sensations from the human test subjects. Velocities had to be diminishes by around three times (\(\sim\)0.6 m/s) to reduce the unpleasant sensations of draft [33]. PV airflow on the face can substantially reduce exposure, regardless of the location of the pollution source. Local exhaust ventilation integrated into seats may reduce exposure. [PERSON] et al. [50] investigated how the performance of a desk-mounted PV system may be affected by the presence of two personalized exhaust (PE) systems above shoulder level. Their study found that such an integration introduced more PV air into the breathing zone and exhausted part of the exhaled air with the free convective flow. PV diffusers in proximity of the human face also reduce exposure of the eyes due to the protective effect of the flow of fresh air if the PV can target the occupant's breathing zone, which is rarely the case when the distance between the head and the PV diffuser is significant, in which case an increased frequency of eye blinking has been reported [34]. Considering the previous results, we propose to install a six-lobed PV diffuser situated in proximity to the occupant at a distance of 0.06 m (equivalent to 2 De, based on previous studies [31]). This PV diffuser geometry and distance enable the PV jet to supply fresh air to a wider region around the face, compensating for small changes in head position. The aim of the present paper is to study the possibility of using a low-momentum PV system that can penetrate a passenger's convective boundary layer, improving air quality in their breathing zone. A successful implementation of such a PV solution is the first step towards increasing passenger protection against airborne pathogens. The evaluation of the proposed PV solution is analyzed using numerical simulations, supported by experimental measurements for validation purposes, allowing us to make preliminary conclusions about the efficiency of such systems.