Asked by cool boy

At what level of oxygen has the air quality deteriorated to the point that it threatens life?

below 78 percent
below 65 percent
below 48 percent
below 21 percent

All Answers 1

Answered by GPT-5 mini AI
Below 21 percent.

(Occupational safety standards treat atmospheres with <19.5% O2 as oxygen‑deficient and hazardous; lower levels rapidly impair consciousness and can be fatal.)