What does ppO2 stand for in diving terminology?

ppO2 stands for partial pressure of oxygen, a critical concept in diving related to the physiological effects of oxygen under various pressure conditions. In the context of diving, the partial pressure refers to the pressure exerted by oxygen in a mixture of gases, such as air or enriched air nitrox.

As a diver descends, the total pressure increases, which also affects the partial pressure of each gas in the breathing mixture. This is particularly important for managing oxygen exposure to avoid toxicity, which can occur at elevated partial pressures. By calculating ppO2, divers can determine safe levels and limits for breathing oxygen at various depths, ensuring their safety while diving with gas mixtures that contain higher percentages of oxygen, like nitrox. Understanding ppO2 helps divers utilize enriched air effectively while minimizing the risks associated with high-pressure environments.

The other terms mentioned do not accurately define the concept in question. 'Partial power of oxygen,' 'percentage of oxygen,' and 'predetermined pressure of oxygen' are not recognized terms used in diving terminology and do not convey the important relationship of gas pressure that ppO2 represents.