This research investigated a couple of aspects of CO emissions from car vehicles. Firstly, it explored the influence of varying the number of vehicles in operation. Secondly, it analysed the significance of exhaust vents affecting the concentration of CO through parking space lots. The conducted analysis relied on simulation data obtained using ANSYS-Software, as opposed to experimental data. The accuracy of the natural ventilation model was validated. The impact of various running vehicles was examined, including those with half, partially, and fully-loaded. The objective was to determine the correlation between the number of running vehicles and the increase in CO concentration. In addition, several configurations of exhaust vents were examined for the fully loaded scenario. As a result, it was shown that the architectural layout has an impact on the natural ventilation system, which may not be suitable for human health, especially when dealing with greater car emission rates.