Table 14.1.

Health effects on humans owing to CO2 concentration in the air

CO2 concentration (percentage in air)Exposure timeHealth effectsOccupational exposure limitObservations
0.039Atmospheric air
0.58 h/day in a work environmentPermissible exposure limit
0.5–3.0Several hoursDifficulty in breathing
Increase in the cardiac rhythm
Headache
3.015 minShort-term exposure limit
>15 min100% breathing rhythm accelerates
Headache
Muscle weakness
5.0300% breathing rhythm accelerates
Headache
Muscle weakness
Depression
Sickness
Vertigo
Noise in the ears
Somnolence
10.0Several minutesUnconsciousness. Quick recovery when the person is moved to a ventilated environment
>15.0Lethal concentration. Unconsciousness and death
  • Based on NIOSH/OSHA (1981), Le Guern et al. (1982), Blong (1984), Wong (1996) and Williams-Jones & Rymer (2000).