How Oxygen Levels are Maintained in an Aeroplane at High Altitudes

The percentage of oxygen in the atmosphere remains constant, but as altitude increases, the pressure of air decreases. This means that at higher altitudes, the air becomes thinner, making it harder for the body to absorb the necessary amount of oxygen. To maintain a comfortable and safe flying environment, airplanes are equipped with a pressurization system that ensures the cabin pressure remains at a level where the oxygen is more readily available to all passengers and crew.

Cabin Pressurization System

The cabin pressurization system works by taking in outside air and pressurizing it to a level equivalent to a lower altitude. This is achieved by using compressed air from the engines. Here's how it works in different types of planes:

Piston Engine Planes

In piston engine planes, pressurized air is taken from the engine's turbocharger, which then cools the air through a heat exchanger in the wings. This cooled and pressurized air is then piped into the cabin, ensuring the pressure is maintained at a level that makes breathing easier.

Jet Engine Planes

Jet engine planes use a different method. Air is drawn from the compressor section of the jet engine, heated to about 900 degrees Fahrenheit, and then cooled down through various heat exchangers and environmental air packs. This cooled and pressurized air is then used to maintain the cabin pressure at an equivalent of about 7,000 feet altitude.

Regardless of the method, the goal is to create a pressurized environment that reduces the altitude to about 7,000 feet, ensuring the oxygen molecules are more accessible to breathe. A typical jet airliner will maintain this level of pressure, even when flying at much higher altitudes, such as 35,000 feet. This means that passengers experience the same level of oxygen as they would at an elevation of 7,000 feet, which is approximately the altitude of Denver, Colorado.

Oxygen Levels in the Airplane

The air outside the plane is the same as at ground level in terms of oxygen content, containing approximately 21% oxygen. However, because it is thinner, the oxygen concentration is more dispersed, making it harder to breathe. This is why the cabin is pressurized to mimic a lower altitude. The pressure inside the plane is equivalent to an altitude of 5,000 to 6,000 feet, which is why most commercial planes have an altitude equivalent to around 7,000 feet.

What Happens in Case of Depressurization

In the event of a cabin depressurization, commercial planes are equipped with chemical oxygen generators. These generators are positioned over each group of seats and provide enough oxygen to last for 10 to 15 minutes. This is sufficient time for the plane to descend to a lower altitude where the air is breathable.

Thus, through precise control of the cabin pressure, the aircraft ensures a safe and comfortable flying experience for all passengers and crew, even at high altitudes. Modern technology has made it possible to maintain the same level of oxygen availability regardless of the external altitude, ensuring a pleasant and healthy environment for everyone on board.