What is the typical nitrogen percentage in air that divers are familiar with?

The typical nitrogen percentage in air that divers are familiar with is approximately 78%. This composition is consistent with the molecular makeup of Earth's atmosphere, where nitrogen makes up the largest portion. Understanding this percentage is crucial for divers, especially when considering the effects of nitrogen on the body during descents and ascents. The dive planning process, particularly for managing nitrogen absorption and decompression limits, relies on this foundational knowledge of air composition.

In diving, being aware that nitrogen constitutes such a significant percentage of the air helps divers appreciate the risks of nitrogen narcosis and decompression sickness, both of which are influenced by this gas's partial pressures as divers explore various depths.