What are safe levels of CO and CO2 in rooms?

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CO₂	250-350ppm	Normal background concentration in outdoor ambient air
	350-1,000ppm	Concentrations typical of occupied indoor spaces with good air exchange
	1,000-2,000ppm	Complaints of drowsiness and poor air.
	2,000-5,000 ppm	Headaches, sleepiness and stagnant, stale, stuffy air. Poor concentration, loss of attention, increased heart rate and slight nausea may also be present.
	5,000	Workplace exposure limit (as 8-hour TWA) in most jurisdictions.
	>40,000 ppm	Exposure may lead to serious oxygen deprivation resulting in permanent brain damage, coma, even death.
CO	9 ppm	CO Max prolonged exposure (ASHRAE standard)
	35 ppm	CO Max exposure for 8 hour work day (OSHA)
	800 ppm	CO Death within 2 to 3 hours
	12,800 ppm	CO Death within 1 to 3 minutes

2013