What level of oxygen in air can be fatal?

What level of oxygen in air can be fatal?

• A. 20%
• B. 25%
• C. 15%
• D. 30%

Answer: (C)

The level of oxygen in air that can be fatal is more accurately represented by 15%. Normal atmospheric air contains about 20.9% oxygen, which is essential for human life. When the oxygen concentration drops to about 19.5% or lower, individuals may begin to experience symptoms of oxygen deficiency, such as dizziness, shortness of breath, and impaired cognitive function. At 15% oxygen concentration, the risk of loss of consciousness and even fatality increases significantly due to hypoxia, where inadequate oxygen is available to sustain normal bodily functions. This can lead to critical situations where brain damage or death may occur if exposure is prolonged. The other choices, at 20%, 25%, and 30% oxygen levels, represent conditions that are either within the safe range or significantly above normal atmospheric levels, and thus do not pose the same fatal risks as lower concentrations like 15%.

The level of oxygen in air that can be fatal is more accurately represented by 15%. Normal atmospheric air contains about 20.9% oxygen, which is essential for human life. When the oxygen concentration drops to about 19.5% or lower, individuals may begin to experience symptoms of oxygen deficiency, such as dizziness, shortness of breath, and impaired cognitive function.

At 15% oxygen concentration, the risk of loss of consciousness and even fatality increases significantly due to hypoxia, where inadequate oxygen is available to sustain normal bodily functions. This can lead to critical situations where brain damage or death may occur if exposure is prolonged. The other choices, at 20%, 25%, and 30% oxygen levels, represent conditions that are either within the safe range or significantly above normal atmospheric levels, and thus do not pose the same fatal risks as lower concentrations like 15%.