Carbon Dioxide can impair cognitive function

Likelihood of Claim: Somewhat Likely

Quality of our research survey: Partial

Traditionally in indoor environmental studies, carbon dioxide, being easy to measure, has been used as a proxy to estimate the number of other indoor air pollutants present in a low ventilated environment. Up until the early 2000s, carbon dioxide was not considered a pollutant itself unless at extremely high levels that could only occur in industrial settings. The primary source of carbon dioxide in indoor environments is human respiration. Due to energy conservation regulations, indoor ventilation requirements for office spaces was actually reduced in the latter half of the 20th century.

Since the early 2000s there have been some efforts to isolate the effects of carbon dioxide on human health and cognitive ability in settings that mimic the work and school environments humans regularly encounter. Two high quality studies have been conducted, one in 2012, and a follow up in 2016 that show a statistically significant connection to decreases in cognitive performance when exposed to higher levels of carbon dioxide, that could plausibly exist in common indoor environments.

What stands those two studies apart is their use of a sophisticated cognitive testing tool, called the Strategic Management Simulation (SMS) that tests a wide variety of cognitive functions rather than basic "office work" cognitive tests that are often typing text and measuring accuracy, or adding double digit numbers together. Since there are only two studies that have shown a direct link, we think more research is still needed, especially since the mechanism that could cause the decline in cognitive performance is not understood.