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Monday, November 25, 2019

Scully et al. (2019) -- Do Elevated Levels of CO2 Negatively Impact the Human Brain?

Scully, R.R., Basner, M., 
Nasrini, J., Lam, C.,
Hermosillo, E., Gur, R.C., 
Moore, T., Alexander, D.J., 
Satish, U. and Ryder, V.E. 

2019

Effects of 
acute exposures 
to carbon dioxide on 
decision making and 
cognition in 
astronaut-like 
subjects. 

Microgravity 5: 17; 



Rising levels 
of atmospheric CO2 
pose no direct threat 
to human health 
(see Liu et al., 2017
 and Monsé et al., 2019). 

What about 
human cognition 
and decision making?

Scully et al. (2019) 
are ten U.S. researchers 
who tested the 
mental acuity 
of 22 "astronaut-like" 
male and female 
subjects 
to four different 
CO2 concentrations 
(600, 1200, 2,500 
and 5,000 ppm).

The subjects took 
standardized 
decision making 
and cognition tests 
(the Strategic 
Management 
Simulation 
and Cognition 
test batteries), 
routinely conducted 
on astronauts 
at the Johnson 
Space Center. 

According to the authors,
 "there were no clear 
dose-response patterns 
for performance 
on either [the] Strategic 
Management Simulation 
or Cognition" 
evaluations. 

They report that 
"performance on most 
Strategic Management 
Simulation measures 
and aggregate speed, 
accuracy and efficiency 
scores across Cognition 
tests were lower 
at 1200 ppm 
that at baseline 
(600 ppm); however, 
at higher CO2 
concentrations 
performance w
as similar to 
or exceeded 
baseline for 
most measures" 

Overall, they conclude
"performance 
across tests 
did not differ 
between 
baseline (600 ppm) 
and the higher 
concentrations."

Their findings agree with 
Rodeheffer et al. (2018), 
who demonstrated rising 
atmospheric CO2 levels 
represent no direct threat 
to human cognitive 
performance and 
decision making. 

This study adds to the 
growing body of evidence 
of no negative impacts 
of rising atmospheric CO2
on human health.


The chart below shows  
a mean ± 95% confidence 
intervals of percentile ranks
for Strategic Management 
Simulation measures at 
targeted CO2 
concentrations:











References
Liu, W., Zhong, W. 
and Wargocki, P. 
2017
Performance, acute 
health symptoms and 
physiological responses 
during exposure to 
high air temperature 
and carbon dioxide 
concentration. 

Building and Environment 114: 96-105.




Monsé, C/. Jettkant, B., 
Schramm, B.K.H., Broding, H.C., 
Knappe, M., Michl, M., Hoffmeyer, F., 
Sucher, K., Brüning, T. and Bünger, J. 
2019
Effects of exposure 
to carbon dioxide 
in potash miners. 

Advances in Experimental Medicine 
and Biology - Neuroscience 
and Respiration 42: 1-10.




Rodeheffer, C.D., Chabal, S., 
Clarke, J.M. and Fothergill, D.M. 
2018 
Acute exposure to 
low-to-moderate 
carbon dioxide levels and 
submariner decision making. 

Aerospace Medicine 
and Human Performance 89: 520-525.