<p>In this work, indoor air quality in a fitting room fitted with mixing ventilation (MV) and displacement ventilation (DV) systems is examined using the computational fluid dynamics (CFD) approach. The two ventilation systems capacity to remove the airborne pollutant from the room is measured using the mean age of air technique. Air quality in the room is also evaluated using indicators such as ventilation efficiency and air change effectiveness. The findings showed that the placement of the inlet and outlet, in addition to the kind of mechanical ventilation system, affect the delivery of fresh air to the occupants and either attenuate or intensify the spread of pollutants in the room space. When compared to the MV system, the evaluation showed that the DV system performs successfully in terms of the system capacity to distribute air and remove internally produced pollutants. In fact, the benchmarking showed that the DV system works well since it offers little contamination dispersion in the room space and exhibits a better quantity/quality of fresh air at the breathing level.</p>