| Concentration | Concentration | Effect on the human organism |
| O2 (%) | CO2 (%) | (CO2 increase) |
| 21 | 0.03 | natural concentration in the air |
| 0.5 | MAK-Value | |
| 20.5 | 2.5 | no effect |
| 20.4 | 3 | breathing will be more intense and also deeper, headache, heart palpitations, slower pulse, tension, dizziness, faintness |
| after ½ to 1 hour: mortal | ||
| 20.2 | 4 | |
| 20.1 | 4.5 | ½ a 1 hour:(almost) immediately mortal, the higher breathing rate is subjecively noticeable |
| 19.7 | 6.1 | |
| 19.3 | 8 | serious lack of breath, unconsciousness comes fast, followed by death caused by a too high concentration of CO2 in the blood |
| 18.9 | 10 | |
| 16.8 | 20 | within a few seconds, the central nervous system is paralysed |
| 6 | 71 |