What does the cabin pressurization system control regarding air?

The cabin pressurization system is crucial for maintaining a safe and comfortable environment for passengers and crew at high altitudes. One of its primary functions is to regulate the rate at which air exits the cabin to ensure that the cabin remains at the appropriate pressure level. While the cabin is pressurized, any excess air must be expelled in a controlled manner to prevent over-pressurization. This management of air flow helps maintain a stable cabin pressure, which is vital for the comfort and safety of everyone on board.

This option highlights the system's role in venting excess air, which is essential for preventing pressure build-up and ensuring that the cabin remains pressurized at levels suitable for human physiology. Understanding this aspect is important for aircrew members, as it impacts the overall functioning of the aircraft's environment during flight.