Normal CO2 Levels
The effects of CO2 on adults at good health can be summarised to:
- normal outdoor level: 350 – 450 ppm
- acceptable levels: < 600 ppm
- complaints of stiffness and odors: 600 – 1000 ppm
- ASHRAE and OSHA standards: 1000 ppm
- general drowsiness: 1000 – 2500 ppm
- adverse health effects may be expected: 2500 – 5000 ppm
- maximum allowed concentration within a 8 hour working period: 5000 – 10000 ppm
- maximum allowed concentration within a 15 minute working period: 30000 ppm
CO2 levels in commercial offices are maintained by the air handling units. In older offices windows are opened.
Maintaining healthy CO2 levels is important for the welfare and productivity of staff.