What is the primary reason divers use nitrox mixtures?

Divers primarily use nitrox mixtures to increase bottom time. Nitrox, specifically enriched air nitrox with a higher percentage of oxygen (usually between 32% to 40%), allows divers to extend their time underwater without exceeding the no-decompression limits when compared to regular air, which is about 21% oxygen and 79% nitrogen.

The increased oxygen content in nitrox reduces the percentage of nitrogen, which plays a significant role in the risk of nitrogen narcosis and decompression sickness. By decreasing the amount of nitrogen being absorbed by the body during a dive, divers can safely spend longer periods at certain depths, making it an advantageous choice for dives where extended bottom time is desired.

Other options such as reducing equipment weight, negating the effects of cold, or enhancing buoyancy do not accurately reflect the benefits of using nitrox. While divers may experience improved comfort or buoyancy control through different equipment or methods, the primary motivation remains the extended dive time effectively afforded by nitrox mixtures.