Which gas is primarily responsible for increased narcosis effects during deeper dives?

Nitrogen is primarily responsible for increased narcosis effects during deeper dives due to its properties and behavior under pressure. As a diver descends, the partial pressure of nitrogen increases, which enhances its solubility in body tissues. This can lead to a narcotic effect similar to alcohol intoxication, which impairs judgment, coordination, and other cognitive functions.

Narcosis, often referred to as "depth narcosis" or "the rapture of the deep," occurs when the brain becomes flooded with nitrogen due to the increasing pressure, making divers less aware of their surroundings and more prone to make poor decisions. The effects of nitrogen narcosis can be exacerbated at greater depths, as the nitrogen saturation increases significantly.

While other gases like oxygen, helium, and carbon dioxide can affect a diver's experience, nitrogen is the predominant gas linked with narcosis at depth, particularly when diving with air or standard nitrox mixtures. Oxygen toxicity, which can occur at high partial pressures of oxygen, and high levels of carbon dioxide, which can lead to hypercapnia, do not directly correlate with depth-related narcotic effects like nitrogen does. Helium is often used in technical diving to reduce narcosis symptoms, as it has a