Study Suggests Human Exposure To 20,000 ppm CO2 Has No Effect On Cognition, Health

An observational assessment undermines claims that elevated CO2 levels are harmful to humans. 

Every year there are several papers published attempting to establish CO2 as a pollutant in indoor settings. This has likely served to scare people to regard elevated CO2 levels as dangerous – which is almost certainly the intent.

For example, I have noticed that on my home CO2 monitors the facial symbol denoting healthy vs. unhealthy concentrations vary from a smiley face below 600 ppm to a frowny face when the room CO2 rises to over 1,o00 ppm…and a straight face between 600 and 999 ppm.

Every day children are exposed to air CO2 levels of 2,000 ppm, 3,000 ppm and up in their school classrooms (Corsi et al., 2002). Somehow they manage to survive.

Image Source: Corsi et al., 2002

Dr. Alberto Boretti (2021) points to the ridiculousness of stoking fear about indoor air with 1,000 CO2 and up considering the plethora of evidence available saying these levels are not harmful to humans.


“It has been claimed that the dangerous rise in atmospheric CO2 levels will impede our brain functions, and namely that the continued fossil fuel emissions will impair cognition. In particular, it is said that indoor CO2 levels may reach levels well above 1,000 p.p.m. and this may be harmful to cognition by the end of this century.”

And now in another new study scientists (Maniscalco et al., 2021) report they have observed no adverse physiological or cognitive-related differences when exposing average office workers to CO2 concentrations of 770 versus 20,000 ppm.

“[T]he human body can adapt to high concentrations of pure CO2 (20 000 ppm) without adverse effects on physiological or psychological parameters. Our results  provide additional confirmation that negative health effects at high indoor air CO2 concentrations cannot be attributed to CO2 but are most likely caused by other pollutants.”

“In terms of accuracy and speed in the three cognitive performance tasks, no significant changes were found at exposure to 20 000 ppm CO2 compared to 770 ppm.”

“Our findings our in accordance with earlier research that found null effects of CO2 on cognitive performance with exposures between 5000 and 20 000 ppm CO2 with or without exercise.”

Yet another scare tactic has been contravened using real-world observational evidence.

Image Source: Maniscalco et al., 2021
Updated: January 6, 2022 — 10:06 pm

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