What determines the maximum surfacing nitrogen levels in diving models?

The maximum surfacing nitrogen levels in diving models are primarily determined by the controlling compartment. In diving physiology, the body is divided into various compartments that absorb and release nitrogen at different rates. The controlling compartment is the one that dictates the overall nitrogen loading and unloading for the diver, as it has the fastest kinetics. This means that the compartment with the highest saturation of nitrogen will significantly influence the recommendations for safe ascent and surfacing.

While the other factors, such as depth of the dive and dive duration, play roles in determining how much nitrogen is taken up during the dive, they do not directly dictate the maximum levels of nitrogen when surfacing. Surface water temperature might affect various physiological aspects of diving but does not influence nitrogen levels directly as the controlling compartment does. Thus, focusing on the controlling compartment provides the clearest insight into nitrogen management in the context of diving safety.