How is the partial pressure of oxygen in a Nitrox mixture determined?

The partial pressure of oxygen in a Nitrox mixture is determined by multiplying the fraction of oxygen in the mixture by the ambient pressure. This process relies on Dalton's Law of Partial Pressures, which states that in a gas mixture, the total pressure is equal to the sum of the partial pressures of each individual gas.

In the context of Nitrox, which is a blend of oxygen and nitrogen, the fraction of oxygen (expressed as a percentage or decimal in the mixture) is multiplied by the total ambient pressure to yield the partial pressure of oxygen. This is crucial for divers because it helps them understand the oxygen exposure they are getting at different depths and situations.

Other methods, such as subtracting the nitrogen fraction or summing all gas pressures, would not accurately yield the partial pressure of oxygen in this context. Additionally, while oxygen sensors can measure concentration, they do not directly calculate the partial pressure without considering the ambient pressure. Thus, correctly using the fraction and ambient pressure is essential for safe and effective diving practices.