What if there were a way to get more bottom time while reducing your risk of getting decompression sickness on most dives? That sounds like something every diver would want, so it’s no surprise that PADI’s Enriched Air Diver (also called nitrox) is the most popular specialty course among divers the world over.

“Nitrox certifications make up about 70 percent of all the courses we teach,” says Jay Roberts, operations manager for the Aggressor Adventures fleet of liveaboards. “And I’d say around 90 percent of divers on our boats use nitrox.”

Benefits

Enriched air nitrox is a mixed gas available at most dive centers around the world. It’s made by blending pure oxygen with the air in a dive tank. An example of a common nitrox blend is 32 percent oxygen—the air we breathe at the surface has about 21 percent.

Increasing the amount of oxygen reduces the amount of nitrogen you breathe. Since nitrogen absorbed by your body is the issue in reducing DCS risk, less nitrogen means longer no-stop times and longer dives within the depth limits for your particular blend. This is especially beneficial when you’re doing multiple dives a day, Roberts notes, as you accumulate less residual nitrogen.

What You’ll Learn

PADI’s Enriched Air Diver is a convenient course to take because it doesn’t require any open-water checkout dives. The specialty course primarily focuses on three aspects of diving with nitrox.

The class starts with a refresher on gas laws and the importance of carefully planning your dives based on the percentage of oxygen in your tank. Because you must make a dive plan based on the exact blend of nitrox in your tank, using an oxygen analyzer is another important skill learned in the course. You’ll also learn how to record the information about each tank of nitrox in your dive log, along with how to set your dive computer for the specific blend used on each dive.

Prerequisites

The only prerequisite is an Open Water certification (or Junior Open Water and a minimum age of 12).