What component of nitrox is primarily responsible for extending no-decompression limits?

The correct response highlights that nitrogen is the component of nitrox primarily responsible for extending no-decompression limits. When divers use nitrox, which is a mixture of oxygen and nitrogen with a higher concentration of oxygen than normal air, the reduction of nitrogen in the breathing mixture plays a critical role in decreasing nitrogen absorption during dives.

By using nitrox with a lower nitrogen content compared to air, divers can experience reduced nitrogen loading in their tissues. This means that they can stay underwater longer without exceeding safe no-decompression limits, thereby allowing for extended dive times. The main advantage here is the decreased risk of decompression sickness, as the body absorbs less nitrogen which is the gas primarily associated with this risk.

While other components like helium are sometimes used to further reduce narcosis or for deep dives, in the context of standard nitrox (EANx) mixtures, it is the reduction of nitrogen that most significantly impacts no-decompression limits. Similarly, while oxygen is beneficial in terms of increasing the percentage of usable gas, it does not directly extend no-decompression limits in the same way nitrogen reduction does.