Is CO2 an Indoor Pollutant?


Direct Effects of Low-to-Moderate CO2 Concentrations on Human Decision-Making Performance


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We often don’t think of carbon dioxide as something to be concerned about… unless it’s about rising greenhouse gasses and the impacts of climate change. More often we associate CO2 with the bubbles in water, or maybe what plants use to make oxygen.

Within the indoor biome, it’s very easy for humans to exhale a lot of carbon dioxide and create levels of CO2 indoors that would never be found outdoors.

Outdoor air generally has about 415 parts per million (ppm) of carbon dioxide in it. Trees and plants turn this stuff into oxygen and- in general- things stay balanced. Indoors is another topic. We often don’t have trees and ecosystems to clean air for us, so we end up spending hours in our own air pollution soup.

It takes almost no time for a few people in a conference room to blow past 600 ppm - an admirable indoor goal- and reach remarkably high levels of indoor CO2.

For six of nine measures of decision making, scores were reduced by 12% to 23% at 1000 ppm vs. 600 ppm; For 7 of nine measures of decision making, scores were reduced 44% to 94% at 2500 ppm vs. 600 ppm; For one measures of decision making, score increased by 20% at 2500 ppm vs. 600 ppm.

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Usha Satish

Mark J. Mendell

Krishnamurthy Shekhar

Toshifumi Hotchi

Douglas Sullivan

Siegfried Streufert

William J. Fisk


Department of Psychiatry and Behavioral Science, Upstate Medical University, State University of New York, Syracuse

Indoor Environment Department, Lawrence Berkeley National Laboratory

Link to Publication