Oxygen and Human Requirements
How much oxygen is needed to remain in the air
before a person goes unconscious?
This would vary greatly depending upon the condition of the person.
The following site offers an approximation:
* 20.9-23.5 percent: Maximum permissible oxygen level. No effect.
* 20.9 percent: Percentage of oxygen found in normal air. No effect.
* 19.5 percent: Minimum permissible oxygen level. No effect.
* 15-19 percent: Decreased ability to work strenuously. May
impair coordination and may induce early symptoms with individuals
that have coronary, pulmonary, or circulatory problems.
* 12-15 percent: Respiration and pulse increase; impaired
coordination, perception, and judgment occurs.
* 10-12 percent: Respiration further increases in rate and depth;
poor judgment and bluish lips occur.
* 8-10 percent: Symptoms include mental failure, fainting,
unconsciousness, an ash-colored-face, blue lips, nausea, and vomiting.
* 6-8 percent: 8 minutes - 100 percent fatal; 6 minutes - 50
percent fatal; 4-5 minutes - recovery with treatment.
* 4-6 percent: Coma in 40 seconds, convulsions, respiration
ceases - death.
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Update: June 2012