Skip to content

What Do High Carbon Dioxide Levels In The Air Do To Thought Processes?

This is a topic that is totally neglected: What will it feel like when the carbon dioxide levels in the atmosphere (the air) increase as our climate changes? What kinds of effects will it have on our thought processes (our cognition)? The reason I mention this is because research shows that as carbon dioxide (CO2) levels increase in rooms with people in them, it feels "stuffy" and people's thinking (cognitive processes) deteriorate. They don't think and work as effectively. Air starts to feel "stuffy" at about 600 ppm (parts per million). Our current CO2 levels in outside air are already above 400 ppm, and the levels are forecast to keep rising.

Indoor air typically has much higher CO2 concentrations than outdoor air because people are exhaling CO2 with every breath. (Note that research shows that urban city centers can already have outdoor CO2 levels above 500 ppm due to the “urban CO2 dome” effect, and elementary school classrooms are frequently above 1000 ppm, with some going as high as 3000 ppm at times). So as CO2 levels rise in the atmosphere with climate change, it will lead to even higher indoor CO2 levels in our workplaces, homes, and schools.

So... with increases in CO2 levels, what if it feels "stuffy" all the time? We won't be able to escape the "stuffiness" by going outside or opening a window. And remember, it will be worse in rooms with people in it, or in cars and aircraft. The research shows increasing CO2 levels make it harder to work and think effectively - think of it as an indoor air pollutant. Holy mackerel! This scary aspect of the effects of rising CO2 levels in the atmosphere needs to be widely discussed and addressed.

The following 2 articles discuss the research showing the negative effects on cognition with increases in CO2 levels (what happens to people's mental processes in crowded classrooms, offices, etc.). 

Excerpts from the writer Brian Gallagher's July 27, 2018 article on Medium: How Climate Change Is Ruining Our Indoor Air

... We were at around 280 ppm [of CO2 in the atmosphere] before we began to burn coal, oil, and gas en masse. This April, we reached 410 ppm.

Yet it is a little appreciated fact that many of us at home, school, and work breathe air containing CO2 concentrations of 1,000 ppm every day. It’s because the air we exhale holds around a hundred times more CO2 — about 40,000 ppm — than the air we inhale. Badly ventilated classrooms and overcrowded conference rooms can reach 2,000 ppm, well above the point when air starts to feel “stuffy,” at 600 ppm. Concentrations above that can cause classic symptoms of CO2 poisoning: labored breathing, headaches, rapid pulse rate, hearing loss, hyperventilation, sweating, and fatigue.

Scientists like William Fisk, who studies the relationship between human health and performance and indoor-air quality at Lawrence Berkeley National Laboratory, worry that long-term exposures to these conditions could be toxic. Even at lower levels, the effect appears to still be strong enough to influence whether kids make it to school.

Even if they do make it to school, high indoor concentrations of CO2 can make it hard for students to concentrate. A couple years ago, Joel Jean, a postdoc at MIT studying solar energy, became alarmed when he read about how common indoor school and work atmospheres can also degrade human cognition. For example, a 2012 study concluded that at “1,000 ppm CO2, compared with 600 ppm, performance was significantly diminished on six of nine metrics of decision-making performance.” At 2,500 ppm, performance levels became more or less “dysfunctional.” A 2014 study found that indoor air quality improvements could be a “more cost-effective way to improve standardized test scores” than reducing class sizes.

A 2016 study upped the ante: Researchers simulated the indoor air-quality of “green,” or LEED certified, buildings along with conventional ones to test the cognitive performance of a group of professionals in a realistic setting. “This study was designed to reflect indoor office environments in which large numbers of people work every day,” the authors wrote. They found that seven of nine cognitive function domains tested in a strategic management simulation decreased as CO2 increased. Employee scores were 15 percent lower in a day spent working at 945 ppm, and 50 percent lower at 1,400 ppm, relative to working under green conditions with elevated ventilation rates.

The growing concentration of carbon dioxide in outdoor air makes all of this worse, for at least two reasons. First, venting outdoor air indoors will become less effective since “fresh” air will itself be stuffier. The more CO2 in the atmosphere, the easier it is for us to build up CO2 concentrations indoors to undesirable levels. How fast indoor concentrations end up rising, and how high they eventually get, depends on, among other things, the ventilation capacity of a space, its volume, the amount of people, and their age, sex, body weight, and level of physical exertion. (A 2017 study outlines how to do this calculation.)

The MIT solar energy researcher Dr. Joel Jean's article discusses how high CO2 (carbon dioxide) concentrations in the air reduce our cognitive performance, our health, and our comfort. Excerpts from Medium: I’m living in a carbon bubble. Literally.

Most of us live with high carbon dioxide (CO2) levels in our offices, bedrooms, classrooms, and cars without ever thinking about it. But recent double-blind studies suggest that CO2 exposure can reduce cognitive and decision-making performance dramatically — by 50% or more at common indoor levels. This is one of the most under-discussed impacts of climate change: It makes us all stupid. I monitored CO2 levels in my bedroom for the last 2 years, and the results are stunning.

The Earth’s atmosphere is about 0.04% carbon dioxide (CO2)—400 parts per million or ppm. But the air we breathe out is 100 times more concentrated in CO2 — around 4% or 40,000 ppm. Every time we exhale, we make the air around us a little less hospitable. Every place we go, we raise CO2 levels.

And where there are lots of people — in our cities, our classrooms, our offices, our homes— CO2 levels rise. A lot. Several studies have measured CO2 concentrations in the human-dense and enclosed places where we spend most of our lives, and the numbers are striking: ...Offices often have CO2 levels of 600 ppm or higher. Only 5% of US offices have average CO2 concentrations above 1000 ppm [Persily 2008], although one study suggests that a typical meeting room can reach up to 1900 ppm CO2 during 30- to 90-minute meetings [Fisk 2010].... Classrooms often reach average CO2 levels above 1000 ppm, as observed across elementary school classrooms in Texas, Michigan, Washington, Idaho, Texas, South Carolina, Sweden, and England [Stafford 2015]. In a 2002 study, 21% of classrooms in Texas had CO2 concentrations over 3000 ppm [Corsi 2002].

Many of us live with high CO2 levels — all day, every day. In a study in Singapore, people carried around CO2 monitors for a week [Gall 2016]. They logged time-averaged CO2 levels of 840 ppm. Nearly all were exposed to above 1100 ppm at least 5% of the time (1.2 hours per day).

But recent studies suggest that CO2 itself is an indoor pollutant. To be specific, a pollutant — according to Wikipedia — is a substance introduced into the environment that has undesirable effects. And CO2 has many undesirable effects, even if we ignore climate change.

... Let me repeat that: Increase CO2 by 400 ppm, and you decrease cognitive function by over 20%.

Remember, CO2 levels in our classrooms, bedrooms, and cars are often above 1000 ppm2000 ppm, and 4000 ppm, respectively—600–3600 ppm above outdoor levels. That means we could be handicapping our brains—as we learn, sleep, and drive—by 50% or more!

To test the effect of ventilation on indoor CO2 levels, I alternated sleeping with my bedroom door open and closed for several days. With the door closed—no ventilation—average CO2 levels increased by over 1000 ppm during the night (overnight average of 2470 ppm ± 560 ppm). With the door cracked open—moderate ventilation—average CO2 levels actually decreased by roughly 500 ppm during the night (overnight average of 1840 ppm ± 860 ppm).

1 thought on “What Do High Carbon Dioxide Levels In The Air Do To Thought Processes?

  1. Val

    Plants have provided nearly all of the 23% oxygen in our atmosphere. Plants breathe carbon dioxide. Greenhouses around the world pump in carbon dioxide to benefit the plants. Atmospheric Equity is needed. Current carbon dioxide levels are at .04%. This is unfair to plants. It’s time to give plants a full 1% carbon dioxide atmosphere.


Leave a Reply

Your email address will not be published. Required fields are marked *