Which factor should a diver analyze to avoid high levels of oxygen toxicity during a dive?

To avoid high levels of oxygen toxicity during a dive, analyzing the mixture of breathing gas used is paramount. Enriched air nitrox contains a higher percentage of oxygen compared to regular air, which increases the risk of oxygen toxicity as the partial pressure of oxygen rises with depth. The deeper the diver goes, the greater the pressure, leading to higher partial pressures of gases being inhaled.

Monitoring the oxygen content in the breathing gas ensures that the diver stays within safe limits. For recreational nitrox diving, this typically involves regulating oxygen concentrations to avoid reaching critical partial pressures that can lead to symptoms of toxicity, such as convulsions and other harmful effects.

While the total dive depth and the depth at which a dive computer is set are relevant, they are secondary to understanding the gas mixture itself. Moreover, the proportion of nitrogen in the gas does not directly contribute to oxygen toxicity, but rather to nitrogen absorption and potential narcosis. Thus, the gas mixture is the critical factor for managing oxygen exposure during a dive.