What distinguishes aviation breathing oxygen from other commercially available compressed oxygen?

The distinguishing feature of aviation breathing oxygen is that it has had all the water vapor removed. This is crucial because moisture in the oxygen system can lead to the formation of ice at high altitudes, which can obstruct flow or damage the equipment. Removing water vapor helps ensure the oxygen remains in a gaseous state and functions reliably in the harsh conditions of aviation environments.

In contrast, other compressed oxygen sources may not undergo such rigorous drying processes, as their primary applications do not require the same level of purity and performance under extreme conditions. Consequently, aviation breathing oxygen is specifically treated to meet the safety and performance demands of aircraft operations.