Carbon Dioxide Detection and Indoor Air Quality
Occupational Health and Safety: Carbon dioxide (CO2) is a byproduct of combustion, as well as a result of the metabolic process in living organisms. Because carbon dioxide is a result of human metabolism, concentrations within a building often are used to indicate whether adequate fresh air is being supplied to the space. Moderate to high levels of carbon dioxide can cause headaches and fatigue, and higher concentrations can produce nausea, dizziness, and vomiting. Loss of consciousness can occur at extremely high concentrations. To prevent or reduce high concentrations of carbon dioxide in a building or room, fresh air should be supplied to the area.
At room temperature, carbon dioxide is a colorless, odorless, faintly acidic-tasting, non-flammable gas. Carbon dioxide is a byproduct of normal cell function and is removed from the body via the lungs in the exhaled air. Carbon dioxide is also produced when fossil fuels are burned.
Surface soils can sometimes contain high concentrations of this gas from decaying vegetation or chemical changes in the bedrock. Depending on the temperature and pressure, carbon dioxide also can exist as a liquid or a solid. In its solid form, carbon dioxide is called dry ice.
Exposure to carbon dioxide can produce a variety of health effects. These may include headaches, dizziness, restlessness, a tingling or pins or needles feeling, difficulty breathing, sweating, tiredness, and increased heart rate.
Carbon dioxide levels and potential health problems are indicated below:
250-350 ppm: background (normal) outdoor air level
350-1,000 ppm: typical level found in occupied spaces with good air exchange
1,000-2,000 ppm: level associated with complaints of drowsiness and poor air
2,000-5,000 ppm: level associated with headaches, sleepiness, and stagnant, stale, stuffy air; poor concentration, loss of attention, increased heart rate and slight nausea may also be present.
>5,000 ppm: This indicates unusual air conditions where high levels of other gases also could be present. Toxicity or oxygen deprivation could occur. This is the permissible exposure limit for daily workplace exposures.
>40,000 ppm: This level is immediately harmful due to oxygen deprivation.