Air: Composed of approximately 21% oxygen and 79% nitrogen, air is the most common gas mixture for recreational diving. The maximum depth is around 55 meters, which is also the typical safe limit for air dives.
Gas | max Depth (m) | PO2 (bar) |
Air | 55 | 1.37 |
Nitrox: This is a mixture of oxygen and nitrogen with a higher percentage of oxygen. Common nitrox blends, sorted by depth, include:
Gas | max Depth (m) | PO2 (bar) |
EAN32 | 34 | 1.6 |
EAN36 | 29 | 1.6 |
Nitrox allows for longer bottom times and reduces nitrogen absorption, thereby decreasing the risk of decompression sickness.