What term describes an atmosphere with an oxygen concentration exceeding the normal level?

An atmosphere with an oxygen concentration exceeding the normal ambient level is referred to as an oxygen-enriched atmosphere. In typical atmospheric conditions, the oxygen concentration is around 21%. When this level rises significantly, it creates an environment that can support combustion more readily, increasing the risk of fires and explosions. Furthermore, an oxygen-enriched atmosphere can pose health risks to individuals, such as an increased potential for oxygen toxicity, if exposure occurs over an extended period or at higher pressures.

Normal air contains an acceptable balance of gases, primarily nitrogen and oxygen. Oxygen-depleted air, on the other hand, refers to environments where oxygen levels are below normal, which creates a suffocation risk rather than an enrichment of oxygen. Hazardous air generally describes an environment with various toxic, flammable, or otherwise harmful components, but it does not specifically refer to oxygen concentration alone. Thus, the correct terminology for an atmosphere with elevated oxygen levels is indeed oxygen-enriched atmosphere.