What is the composition of air commonly used by recreational scuba divers?

The composition of air that is commonly used by recreational scuba divers is primarily made up of approximately 78% nitrogen and 21% oxygen, with traces of other gases like carbon dioxide and argon. This natural mixture of gases is what divers breathe when using standard air tanks.

The high nitrogen content in the air is significant, as it affects aspects like nitrogen absorption during diving, which can lead to decompression sickness if not managed properly. The 21% oxygen is important for respiration and energy production. This standard air composition is safe for breathing at sea level and at recreational diving depths.

Understanding this composition not only helps divers ensure they have the proper mix for their dives, but it also emphasizes the importance of maintaining safe limits regarding oxygen toxicity and nitrogen absorption, which are critical considerations in dive planning and execution.