Joanne Nova
A prize-winning science graduate in molecular biology.
In the interview with Donald Trump, Elon Musk tried to argue that we ought to be limiting carbon dioxide because we are too close to 1,000ppm, where people get headaches. Not to put too fine a point on it, but we breathe out air at 40,000 ppm fifteen times a minute for our entire lives. If 1,000 ppm gave us a headache or made us nauseous, we’d have to hold our breath every time we kissed someone.
@ElonMusk: The point I was making is that, even if CO2 did not cause global warming, it is uncomfortable to breathe air with >1000 ppm of CO2. Given that the outdoor ppm away from cities is now ~420 (lol), it is already getting close to 1000 ppm indoors in cities at times. You can buy a cheap CO2 monitor and measure this for yourself.
As the global base level of CO2 keeps increasing, it will cause air quality in cities to feel stuffy and unpleasant, resulting in drowsiness, poor concentration, and eventually headaches and nausea. That would not be a good future.
And then he quotes CO2meter.com which, ahem, sells CO2 meters, and has an incentive to wildly overstate the problems with CO2, which they do.
CO2 is not the problem, the stale air and other pollutants cause headaches and sleepiness
The point of CO2 meters is not so much to warn us about excessive CO2 levels but to indicate how well the room is ventilated. CO2 levels are just an indicator for air quality. Air with higher 2 levels usually also has higher levels of organic compounds, humidity, body odour, mold, chemicals from furniture and paint (like formaldehyde), and potentially viruses too. When people report headaches and nausea, the high CO2 levels are not the issue; it’s the bioeffluence that causes problems. When researchers do cognitive tests with pure CO2 added to clean air, performances don’t suffer. The stale air is the problem, not the CO2. (See Zhang and Misra where they compared the cognitive effects from badly ventilated air and clean air with high CO2 levels up to 3,000ppm. Problems disappear when they use fresh air plus higher CO2.) Well-ventilated rooms may also be cooler rooms, which might explain why results so often contradict each other.
Classrooms are at 1,000ppm “typically”
While outdoor air is 420ppm, indoor levels of CO2 are commonly 1,000ppm in classrooms every day, and can rise as high as 3,000ppm if all the windows are shut. The recognized occupational health and safety levels for long-term working exposure are 5,000 ppm for eight hours straight, five days a week. It’s no big deal.
The National Collaborative Centre for Environmental Health (Canada) measured schools and buildings and advises that “Typically, in an occupied classroom situation, the recommended level of ventilation would correspond to a CO2 level of approximately 1000-1100 ppm.” Furthermore, they said the “lowest level at which a human health effect (i.e., acidosis) has been observed in humans is 7,000 ppm, and that only after several weeks of continuous exposure in a submarine environment”.
The occupational limits for CO2 recommended by the American Conference of Governmental Industrial Hygienists (ACGIH) are 5000 ppm (TLV-TWA) and 30,000 ppm (TLV-STEL), based on the direct effects on acidification of the blood. — via Marc Morano and Climate Depot
At NASA, The Office of the Chief Health and Medical Officer reports that a typical spacecraft works at around 3,000-7,000 ppm (or o.3-0.7% CO2). The recommended exposure is 5,000, and the permissible exposure limit is 10,000 ppm. Although the flight surgeons found levels of nearly 7,000 were safe and “didn’t affect performance”. On Apollo 13, CO2 levels rose to 20,000 ppm. Sweating and shortness of breath became a problem above 30,000 ppm.
Submariners typically live with CO2 levels of 2,000- 5,000 ppm, and when a small sample of sailors was tested at 600, 2500, or 15,000 ppm, the researchers couldn’t find any difference in results from an 80-minute test on decision-making (Rodeheffer et al). Likewise, in another study at the Johnson Space Centre, people did cognition tests at 600, 1,200, 2,500, and 5,000ppm, and there was no dose-response effect. Results look rather random.
Lowther et al looked at 51 studies in 2021 and found nothing conclusive in terms of harms from CO2 below 5,000ppm. Most studies were confounded, and results were conflicting. Teams of researchers are hunting to find another problem “due to CO2”. If there were a strong negative effect of CO2, it would have shown up by now. Instead, CO2 is only associated with occasional headaches and nausea – probably because it is high in crowded rooms with little ventilation.
One large review in 2019 was described as showing CO2 affected people at levels as low as 1,000ppm, but the paper itself points at the confounding data and uses the words “possible” and “potential effects” and concludes, “We need more studies.”
REFERENCES
Lowther, Scott D., Sani Dimitroulopoulou, Kerry Foxall, Clive Shrubsole, Emily Cheek, Britta Gadeberg, and Ovnair Sepai. 2021. “Low Level Carbon Dioxide Indoors – A Pollution Indicator or a Pollutant? A Health-Based Perspective.” Environments 8, no. 11: 125. https://doi.org/10.3390/environments8110125
Mishra AK, Schiavon S, Wargocki P, Tham KW. Respiratory performance of humans exposed to moderate levels of carbon dioxide. Indoor Air. 2021 Sep;31(5):1540-1552. doi: 10.1111/ina.12823. Epub 2021 May 15. PMID: 33991134.
Rodeheffer CD, Chabal S, Clarke JM, Fothergill DM. Acute Exposure to Low-to-Moderate Carbon Dioxide Levels and Submariner Decision Making. Aerosp
Zhang X, Wargocki P, Lian Z, Thyregod C. Effects of exposure to carbon dioxide and bioeffluents on perceived air quality, self-assessed acute health symptoms, and cognitive performance. Indoor Air. 2017 Jan;27(1):47-64. doi: 10.1111/ina.12284. Epub 2016 Mar 7. PMID: 26825447.
h/t to Willie Soon, Marc Morano, and Climate Depot.
This article originally appeared at JoNova and was republished by CFACT.
