Scuba divers breathing air at increased pressure can suffer from oxygen toxicity—too much oxygen in their bloodstream— when the partial pressure of oxygen exceeds about 1.4 atm. What happens to the amount of oxygen in a diver's bloodstream when he or she breathes oxygen at elevated pressures? How can this be reversed?

Partial pressure refers to the pressure exerted by a single component of a gas mixture. In the context of scuba diving, as a diver descends, the total pressure increases, which also raises the partial pressure of the gases they breathe, including oxygen. This relationship is described by Dalton's Law, which states that the total pressure of a gas mixture is the sum of the partial pressures of its individual gases.

Oxygen toxicity occurs when the partial pressure of oxygen in the bloodstream becomes excessively high, leading to harmful physiological effects. Symptoms can include visual disturbances, seizures, and lung damage. This condition is particularly relevant for divers, as breathing oxygen at pressures above 1.4 atm can overwhelm the body's ability to process oxygen safely, resulting in toxicity.

Reversing oxygen toxicity primarily involves reducing the partial pressure of oxygen in the diver's environment. This can be achieved by ascending to shallower depths where the pressure is lower, thereby decreasing the partial pressure of oxygen in the lungs and bloodstream. Additionally, administering pure oxygen in a controlled environment can help manage symptoms and facilitate recovery.