What percentage of oxygen defines an oxygen deficient atmosphere?

An oxygen deficient atmosphere is defined as an environment where the concentration of oxygen falls below the normal level found in the Earth's atmosphere, which is approximately 21 percent oxygen by volume. The threshold for determining oxygen deficiency is typically set at 19.5 percent oxygen.

At this level, individuals may begin to experience symptoms of hypoxia, which affects their ability to perform tasks effectively and can lead to unconsciousness if the oxygen levels continue to drop. Therefore, recognizing that an atmosphere becomes deficient in oxygen at 19.5 percent is crucial for safety in various environments, particularly in confined spaces or areas where oxygen displacement can occur.

Understanding these thresholds helps in implementing safety measures and ensuring that individuals working in potentially hazardous environments are adequately monitored and equipped with appropriate safety gear or breathing apparatus to mitigate risks associated with low oxygen levels.