Oxygen and Human Requirements

% Atm Oxygen
% sea level Oxygen
   
23.5%
112%
Maximum permissible oxygen level. No effect.
21%
100%
Percentage of oxygen found in normal air. No effect .
19.5%
93%
Minimum permissible oxygen level. No effect.
15%
71%
Decreased ability to work strenuously. May impair coordination and may induce early symptoms with individuals that have coronary, pulmonary, or circulatory problems.
12%
57%
Respiration and pulse increase. Impaired coordination, perception, and judgment occurs.
10%
48%
Respiration further increases in rate and depth. Poor judgment and bluish lips occur.
8%
38%
  8 minutes - 100 percent fatal; 6 minutes - 50 percent fatal; 4-5 minutes - recovery with treatment.
6%
29%
  Coma in 40 seconds, convulsions, respiration ceases - death.