Enriched Air, also known as “nitrox”, is a form of breathing gas that allows divers to extend bottom time and reduce nitrogen loading. It is PADI's most popular specialty course. PADI Enriched Air Diver Online can be completed in as little as an afternoon. After completing your online learning you'll apply the knowledge you've learned by practicing procedures for obtaining and analyzing enriched air with your PADI Instructor. You also have the option of completing two open water enriched air dives. This certification counts towards the PADI Master Scuba Diver rating.