The amount of carbon dioxide in a building is usually related to how much fresh air is being brought into that building. In general, the higher the CO2 level in the building, the lower the amount of fresh air exchange. Therefore, examining levels of CO2 in indoor air can reveal if the HVAC systems are operating within guidelines.
- 400 ppm - average outdoor air level
- 400 - 1,000 ppm - typical level ranges found in occupied spaces with good air exchange
- 1,000 - 2,000 ppm - level associated with complaints of drowsiness and poor air, often resulting in low performance
- 2,000 - 5,000 ppm - also known as the typical occupational limit.
- 5,000 ppm - This is the permissible exposure limit for daily workplace exposures.
- 30,000 ppm - very harmful and hazard levels