👉 The passenger fluid, also known as air or nitrogen, is a critical component of the cabin atmosphere in aircraft. It circulates through the cabin, diluting carbon dioxide produced by passengers' respiration and ensuring a comfortable environment. This fluid is introduced into the cabin via vents and is continuously circulated by the aircraft's air handling system, maintaining a consistent level of oxygen and minimizing carbon dioxide concentrations. By doing so, it helps prevent issues like hypoxia and enhances passenger comfort and safety during flight.