What is considered a safe oxygen level in terms of breathing?

A safe oxygen level for breathing is typically around 20%. This concentration is crucial because it is the percentage of oxygen present in the air that humans require for optimal respiration and overall health. At this level, the body can efficiently extract oxygen from the air and use it effectively for cellular processes, ensuring that organs and tissues receive the oxygen they need to function.

When oxygen levels drop significantly below 20%, individuals may begin to experience symptoms of hypoxia, which can lead to confusion, dizziness, shortness of breath, and in severe cases, unconsciousness. Levels below about 19.5% are considered unsafe for breathing in occupational environments like mines, where any deviations can pose significant health risks.

Thus, while levels of 16% and below are inadequate for normal respiration, and levels above 20% can potentially indicate an environment too rich in oxygen, 20% remains the standard for safe breathing in typical atmospheric conditions.