Does anyone know the level at which Carbon Monoxide renders unconsciousness?

At levels above 200 ppm (not transient, but persistent), you're likely to be rendered unconscious.Does anyone know the level at which Carbon Monoxide renders unconsciousness?
values in parts per million, lifted from wikipedia.





35 ppm (0.0035%) Headache and dizziness within six to eight hours of constant exposure


100 ppm (0.01%) Slight headache in two to three hours


200 ppm (0.02%) Slight headache within two to three hours


400 ppm (0.04%) Frontal headache within one to two hours


800 ppm (0.08%) Dizziness, nausea, and convulsions within 45 minutes. Insensible within two hours.


1,600 ppm (0.16%) Headache, dizziness, and nausea within 20 minutes. Death in less than two hours.


3,200 ppm (0.32%) Headache, dizziness and nausea in five to ten minutes. Death within 30 minutes.


6,400 ppm (0.64%) Headache and dizziness in one to two minutes. Death in less than 20 minutes.


12,800 ppm (1.28%) Death in less than three minutes.





threshold of consciousness is not distinctly defined, because it is not something that we would like to do tests on. however you could assume that passing out would follow after dizziness sets in.