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How often do you find yourself indoors? We are so concerned about the levels of carbon dioxide (CO2) that are found in the outside environment that you may not have any idea on the levels found inside. In fact, indoor CO2 concentrations may be impacting your well-being and your productivity. On average, you and children spend about 90% of time indoors. Knowing about the concentration of this toxic chemical found where you spend most of your time is an opportunity to make a major difference in your health.

Long term exposure to elevated carbon dioxide concentrations has a negative impact on your health, ability to learn, and productivity. As more people fill-up an indoor space then the availability of oxygen is reduced and carbon dioxide levels increases with every breath as a result of natural metabolic processes and respiration. If you are becoming stressed or are in an environment where there is increased physical activity then there will be less oxygen and more carbon dioxide gases located in the enclosed space.

The maximum threshold limit is measured in parts per million (ppm) where continuous exposure can harm your health. The Occupational Safety and Health Administration (OSHA) recommends that 1,000 ppm is the threshold limit where there may be negative health impacts with continuous exposure. On a typical day in a school classroom, the indoor CO2 concentration may start at 600 ppm. During the course of a day, the levels increase to 2,836 and may reach 4,181 ppm. In an office building, the levels range from 350 to 2,500 ppm. There have been negative health impacts at levels below 1,000 ppm. However, severe hazardous health outcomes have been found at levels from 2,000 to 5,000 ppm.

So how is your health impacted by the levels of CO2 in your space? Research indicated there were significant negative outcomes on teaching, learning, and productivity. Work performance is decreased, absenteeism in increased, and your cost of health care goes up.

There are symptoms when you have been spending long periods of time engulfed by elevated levels of carbon dioxide. You may recognize mucus and respiratory problems. You may have difficulty breathing; experienced headaches and dizziness; become tired; unable to concentrate or pay attention to task; and feel restless. Symptoms include sweating, tingling feelings, and your blood pressure may become elevated with an increased heart rate. Pay attention if you begin to have visual and hearing challenges. Extreme impacts include coma, convulsions, and death. Have you or a child complained of any of these challenges?

All is not lost since there are solutions to the indoor air quality hazards. There are different types of equipment that measure the CO2 concentrations found indoors that may be discovered through research or consulting with an expert. The problem may be with the heating, ventilation, air-condition, and ventilation systems (HVAC) that is outdated or not adequately sized in relation to the operating space. Sewer vents and furnace exhaust pipes may be releasing chemicals into the air around the building in question. Cars, buses, landscape equipment, or other fossil fuel combustion engine machinery may be releasing greenhouse gases close to the building. In addition, cigarette smoking impacts air quality when smoke mixes with the buildings indoor air.

The 21st century introduces many challenges that must be addressed due to increased levels of air pollution. There are benefits to paying attention to the environment where you and children spend most of their time. Being informed allows you to be part of the solution and proactive in your health and well-being.

Elizabeth Armstrong, Ph.D.


1 Achilles, C.M., Jean Prout, J.D. Finn, and Gordon C. Bobbett. 2001. Serendipitous Policy Implications from Class-Size-Initiated Inquiry: IAQ?. Journal Code: RIEFEB2002. Accession Number: ED456494

2 Agency for Toxic Substances and Disease Registry. 2013. Website:

3 Erdmann, C.A., K.C. Steiner, and M.G. Apte. 2002. Indoor Carbon Dioxide Concentrations and Sick Building Syndrome Symptoms in the Base Study Revisited: Analyses of the 100 Building Dataset. Proceedings: Indoor Air. Indoor Environment Department. Lawrence Berkeley National Laboratory. Berkeley. California

4 OSHA. What are the Allowable Limits of CO2 Exposure – Carbon dioxide exposure limit PEL and TLV set by OSHA and NIOSH.   Website:

5 Healthy Schools Network, Inc. 2012. Parent’s Guide to School Indoor Air Quality. Journal Code: APR2013.


6 Sundersingh, David and David W. Bearg. 2003. Indoor Air Quality in Schools (IQA): The Importance of Monitoring Carbon Dioxide Levels. Publication code: RIEMAY2004.


7 Wiley, Robert. 2003. My School Makes Me Sick: Cheap Solutions to Environmental Problems in Schools. Journal Code: RIEAPR2004


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