Carbon dioxide (CO2)is a gas that is exhaled by humans during the respiratory process. This gas is measured during Indoor Air Quality studies because it provides a good indication if the ventilation system is bringing in enough fresh air for the amount of people utilizing the space. It is typically measured not as a pollutant, but as an indicator as to whether other pollutants may be in the air.
In other words, whereas it is known that CO2 can cause some sleepiness at levels in the low thousands, it really isn't considered a big deal in and of itself.
A recent study, however, may change all of this.
An experiment performed by Usha Satish et. Al. from the Department of Psychiatry and Behavioral Science at the State University of New York tested the effects of relatively low level CO2 exposure on 22 university students.
The study was performed in a controlled environmental chamber that was designed to simulate an office environment. Basic air quality parameters such as ventilation rate, relative humidity, temperature, and the like, were unchanged during the sessions. Participants were exposed to 600 ppm, 1,000 ppm, and 2,500 ppm carbon dioxide at separate 2.5-hour intervals.
During each of the 2.5-hour the sessions, the students were asked to perform computer-based questionnaires related to air quality and health effects. In the last hour and a half of each session, they were required to complete computer-based exercises designed to test their decision making performance.
Results showed a moderate decreases in decision making abilities for those exposed to 1,000 ppm. The students' decision making abilities were found to be much more substantially affected when carbon dioxide levels reached 2,500 ppm.
These surprising results suggest that Carbon Dioxide, rather than being considered mostly benign to human health, should be considered an indoor pollutant. It shows that, rather than simply looking at the gas as an indicator of ventilation effectiveness, it must be dealt with in and of itself as a legitimate element in the creation and maintenance of a healthy indoor environment.
Cashins & Associates has decades of experience in the evaluation of indoor air quality and the identification of particular IAQ problems. Please contact us today to find out how our highly trained and certified team can help identify problems with the indoor environment before they affect the health and productivity of occupants.
Learn about common idoor air quality parameters and exposure guidelines download our paper now.