What is the primary composition of the air inside the space station?

The air inside the space station is primarily composed of oxygen and nitrogen, much like the air we breathe on Earth. This composition is vital for providing a breathable atmosphere for astronauts. Oxygen is essential for respiration, while nitrogen is used to balance the pressure and create a safe environment for humans in space.

The choice of having oxygen and nitrogen reflects the need for maintaining human physiological functions, as this mixture closely resembles terrestrial air. It helps prevent issues related to hyperoxia (excessive oxygen) and maintains normal atmospheric pressure that would be found on Earth.

Other options involve gases that are either not suitable for maintaining a breathable atmosphere or are present in much smaller quantities. Hydrogen and helium, for instance, are not used in the atmosphere of the space station because they do not support human respiration. Similarly, carbon dioxide and argon are gases that could be harmful or are not abundant enough to serve as a primary atmospheric component.