What carbon monoxide (CO) concentrations and duration correspond to what symptoms?

CO Concentration	Duration of Exposure	CarboxyHb in Blood	Common Symptoms
to 0.01%	indefinite	1-10%	Mild toxicity: slight headache; tightness across forehead.
0.01-0.02%	indefinite	10 to 20%	Worse headache.
0.02-0.03%	5-6 hr	20 to 30%	Throbbing headache.
0.04-0.06%	4-5 hr	30 to 40%	Moderate toxicity: severe headache; weakness, nausea, vomiting; collapse.
0.07-0.1%	3-4 hr	40 to 50%	Faster symptoms; death possible.
0.11-0.15%	1.5-3 hr	50 to 60%	Severe Toxicity: fast pulse and breathing; coma; seizures; death likely.
0.16-0.3%	1-1.5 hr	60 to 70%	Slowed heart and breathing; death.
0.5-1%	15-45 min	70 to 80%	Respiratory failure and death.