What is the primary difference between aviation oxygen and medical oxygen?

The primary difference between aviation oxygen and medical oxygen is that aviation oxygen is specifically manufactured to be 100% oxygen with no moisture content. This is crucial for aviation applications because moisture can lead to the formation of ice in high-altitude environments, which can be dangerous and disruptive to the aircraft's systems.

Aviation oxygen systems must ensure that the delivered oxygen is dry to maintain safety and efficiency during flight, where low temperatures and pressures can exacerbate the presence of moisture. In contrast, while medical oxygen is also intended to be high purity oxygen, it may allow for small amounts of moisture, as its primary concern is providing breathable oxygen rather than maintaining integrity under fluctuating atmospheric conditions like those encountered at high altitudes.

The other options describe aspects that do not accurately represent the key distinctions between these two types of oxygen. For instance, medical oxygen is indeed typically higher in purity than regular industrial oxygen but does not refer back to the main characteristic that sets apart aviation oxygen in terms of its environment-specific requirements.