Enriched Air Nitrox (EANx) — What It Is and Why It Matters
Enriched air nitrox (EANx) is a breathing gas with a higher oxygen percentage than standard air, typically 32% (EAN32) or 36% (EAN36) oxygen. The higher oxygen content reduces the nitrogen fraction, which means slower nitrogen absorption and longer no-decompression limits at the same depth compared to air.
The trade-off is a shallower maximum operating depth (MOD) due to oxygen toxicity limits. EAN32 has a MOD of about 33 meters at 1.4 ppO2, while air can safely be breathed to about 56 meters at the same ppO2 limit. Nitrox-capable dive computers allow you to set the gas mix and will track both nitrogen loading and oxygen exposure limits simultaneously.
Frequently Asked Questions
Do I need special training to use nitrox?
Yes. An Enriched Air Nitrox certification (offered by PADI, SSI, NAUI, and others) is required. The course covers oxygen toxicity, MOD calculations, gas analysis, and how to set your dive computer for nitrox. It is one of the most popular specialty courses.
Can any dive computer handle nitrox?
Nearly all modern dive computers support at least one nitrox mix. Most allow you to set the oxygen percentage between 21% and 40% (or higher on technical models). Always verify and set your gas mix before diving.
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