"High oxygen" diving, "oxygen rich" diving...... So, different names are translated to the term "ENRICHED AIR", which refers to the high oxygen content in the air (>21%) gas mixture of oxygen and nitrogen composition, we use "NITROX" or "nitrogen oxygen mixture" called. 22% - 40% oxygen and nitrogen are usually used for recreational scuba diving.
The use of NITROX diving has its advantages as well as its limitations, but most importantly, the safety of diving (NITROX use development, as well as diving safety).
You can have a safer diving environment after good theoretical training and proper equipment inspection and marking. The development of NITROX has decades of history, is the main commercial and military uses for the first, during this period there have been four degrees to enter the large-scale promotion of recreational diving areas, due to lack of conditions of the basic theory of diving population, to the cost of NITROX is slightly higher, the penetration rate is not ideal and other factors, all fail on the verge of success. At present, the recreational diving system in the world is still dominated by compressed air diving.