What are safe levels of CO and CO2 in rooms?

CO2

250-350ppmNormal background concentration in outdoor ambient air
350-1,000ppmConcentrations typical of occupied indoor spaces with good air exchange
1,000-2,000ppmComplaints of drowsiness and poor air.
2,000-5,000 ppmHeadaches, sleepiness and stagnant, stale, stuffy air. Poor concentration, loss of attention, increased heart rate and slight nausea may also be present.
5,000Workplace exposure limit (as 8-hour TWA) in most jurisdictions.
>40,000 ppmExposure may lead to serious oxygen deprivation resulting in permanent brain damage, coma, even death.

CO

9 ppmCO Max prolonged exposure (ASHRAE standard)
35 ppmCO Max exposure for 8 hour work day (OSHA)
800 ppmCO Death within 2 to 3 hours
12,800 ppmCO Death within 1 to 3 minutes