How much percentage of oxygen do human need to survive?

Question

How much percentage of oxygen do human need to survive?

Answer 1

16% is the minimum we breath in in fire fighting apparatus in the military but they also tell us that you are still exhailing some too.  I'll go with something in that neighborhood...

Answer 2

20%

Answer 3

21% normal

17% anoxia

10-14% dizzy

6-8% collapse

3-6 % death by asphyxiation within 6-8 min

<3 % death in 45 sec

navy marine corps and occupational safety health rules said that a person should wear a breathing apparatus when oxygen is 19.5 %, a pilot should put on the mask at 12,000 ft

Answer 4

Humans need an atmosphere of about 16-17% oxygen to survive The percentage can dip but only at low depths where the high pressure compensates. At sea level the percentage is 17%. Of course the real percentage varies according to different factors.

Answer 5

50

Answer 6

About 20 percent of oxygen.