When the concentration of carbon monoxide in the air reaches 50 ppm, healthy adults can withstand it for 8 hours
When the concentration of carbon monoxide in the air reaches 200ppm, healthy adults will have slight headache and fatigue after 2-3 hours
When the concentration of carbon monoxide in the air reaches 400ppm, healthy adults have forehead pain within 1-2 hours and life-threatening after 3 hours
When the concentration of carbon monoxide in the air reaches 800ppm, healthy adults will have dizziness, nausea and spasm within 45 minutes, lose consciousness within 2 hours and die within 2-3 hours
When the concentration of carbon monoxide in the air reaches 1600ppm, healthy adults will have headache, dizziness and nausea within 20 minutes and die within 1 hour
When the concentration of carbon monoxide in the air reaches 3200ppm, healthy adults will have headache, dizziness and nausea within 5-10 minutes and die within 25-30 minutes
When the concentration of carbon monoxide in the air reaches 6400ppm, healthy adults will have headache, dizziness and nausea within 1-2 minutes and die within 10-15 minutes
When the concentration of carbon monoxide in the air reaches 12800 ppm, healthy adults die within 1-3 minutes