Carbon Dioxide In Rooms

Indoor air in a room becomes stale, when there are too many people in that room. This is mostly caused by high concentration of carbon dioxide (CO₂). Carbon Dioxide levels that are unusually high may cause room occupants to feel unwell and drowsy. This can be combined with symptoms of headache, lack of concentration and deterioration in performance.

Humans absorbs oxygen (O₂) from the inhaled air and exhale carbon dioxide (CO₂) to the air. The amount of CO₂ in a given air sample is expressed as parts per million (ppm).

It is important to maintain adequate indoor air quality in public places like schools and offices, since workers and students spend half their waking hours there. Using CO₂ as an indicator of ventilation, ASHRAE (American Society of Heating and Air Conditioning Engineers) has recommended indoor CO₂ concentration be maintained at or below 1000ppm in schools and 800 ppm in offices.

The measurement of carbon dioxide is important to ensure adequate fresh air ventilation while simultaneously saving energy by reducing the loss of conditioned air from over-ventilation. Technological breakthrough have made it possible to use relatively inexpensive CO₂ sensors to continuously monitor the CO₂ in rooms.

CO₂ concentration values can be used by HVAC (Heating, Ventilation and Air Conditioning) system to automatically modulate the volume of fresh air to maintain targeted CO₂ level. This strategy is known as CO₂- Demand Controlled Ventilation (DCV). This ventilation system can track occupancy level and provide air ventilation as required.