This article comes from the WeChat public account: Neural Reality (ID: neureality) , author: Robinson Meyer, translation: the art of war, cover: IC photo
Chris Cornasque, Professor of Marine Science at the University of Coronado (Kris Karnauskas) began to carry a pocket-sized Carbon dioxide detectors are walking around the campus. He did not do this to measure the amount of carbon pollution in the atmosphere-he was more interested in the amount of carbon dioxide in the room.
He told me: “I do the same at home, but it’s just fun. After a whole night, the carbon dioxide concentration will immediately exceed one thousandth of a million.” He added, even here-he pointed to Moscone The basement of the Convention and Exhibition Center (The Moscone Convention Center) , which is about the size of a block, is filled with thousands of people to participate in large annual scientific conferences Earth Scientist-The carbon dioxide concentration there may exceed 500 parts per million.
He is concerned about the concentration of carbon dioxide in the room-but the reason is unusual. Konaske is concerned that indoor carbon dioxide levels have become so high that they begin to affect human cognition. In other words: Carbon dioxide, a colorless and odorless gas that also causes global warming, may make us dumb.
Australia ’s ash smothered Sydney. This fire released about 195 million tons of carbon dioxide this year, which is equivalent to the normal carbon dioxide emissions of half a country. —Reuters
He said: “This is an invisible effect of climate change … may really affect our ability to solve the problem itself.”
He recently proposed this idea at the National Geographic Fall Conference (the largest annual meeting of earth and space scientists) . He was also in an article with (Shelly Miller) , Shirley Miller, Professor of Mechanical Engineering, University of Coronado Science professor Anna Scopello (Anna Schapiro) mentioned it in the online paper in cooperation [1] . This paper, which has not yet been peer-reviewed, is uploaded to a paper website where the discussion can be at an early stage or intriguing.
* Note https://psychology.sas.upenn.edu/people/anna-schapiro
Indoor carbon dioxide damages the brain?
At first glance, science is unexpectedly decisive. Researchers have long believed that extremely high concentrations of carbon dioxide can damage the brain.
Anyone who has seen the movie “Apollo 13” (Apollo 13) (or know the real life story behind it) may think of this A snippet: Three astronauts on mission observed that a detection device in the cabin began to report that a gas had reached a dangerous level, and that instrument was measuring carbon dioxide. The movie’s NASOne of the A engineers commented that [2] , if the carbon dioxide level rises too high, “your judgment will be impaired, dizzy, and brain hypoxia will begin to appear.”
“They know that if the value of the detector becomes very high, then they will become stupid, and even 2 + 2 will not be counted.” Konasque said. He proposed that similar universal laws will soon affect people on the planet. Over the past two centuries, the overuse of fossil fuels has caused the carbon dioxide content in the large air to soar from 280 parts per million before the industrial revolution to 410 parts per million today. Overall, pollutants on the earth lock up the heat in the atmosphere, causing climate change. But from a local perspective, it also sets a baseline value for indoor carbon dioxide levels. You cannot lower the indoor carbon dioxide level below the global benchmark.
In fact, because the ventilation system does not work perfectly, the carbon dioxide level in many indoor spaces is much higher than that in the atmosphere. In addition, some indoor spaces, such as offices, hospitals, and schools, are crowded with people who breathe and emit carbon dioxide themselves. Konaske said: “Everyone of us is a small carbon dioxide manufacturing machine.”
He said: “Imagine a meeting room filled with 20 middle-aged people breathing. The carbon dioxide concentration there can easily exceed one thousandth of a million.”
This leads to the last part of his and his colleagues ’discussion: while the concentration of carbon dioxide in the atmosphere continues to rise, so does the indoor carbon dioxide concentration. They predict that, in the worst case scenario, in a crowded room, the concentration of carbon dioxide cannot be reduced to less than 1300 parts per million by ventilation. This may induce some real cognitive impairment. In 2016, researchers at Harvard and Syracuse University found that when indoor carbon dioxide concentration reaches 945 parts per million, human cognitive function will decrease by 15% [3]; and when indoor carbon dioxide concentration reaches one million One thousand and four hundred, human cognitive function will be destroyed to only 50% of the original.
“If carbon emissions are very high, our complex decision-making function may drop to almost half before the end of the century.” Konaske said.
He and his colleagues admitted that this was only a rough estimate. “There is still a lot of work to be done,” he told me. I couldn’t help thinking: “Is this true? Why have I never heard of it before? Carbon dioxide pollution has not only caused global warming, but has it really made us dumb?”
“I will say that it may, but does not necessarily lead to this result.” Eliot Gore (Elliott Gall) *tell me. He is a professor of engineering at the Polish University and studies indoor air quality. In 2015, after some early research on carbon dioxide and cognition came out, he wrote a paper speculating that if the company installs a carbon dioxide filter in the detection system of the office, their work efficiency will be improved 4] .
* Note https://www.pdx.edu/mme/elliott-gall
What cognitive ability is reduced?
“Since then, we have learned more, but we still know very little.” He said that there have been a series of related studies in the past few years. But the results they found were inconsistent.
For example, in a 2016 study, Danish scientists brought indoor carbon dioxide levels to three thousandths of a million [5]-which is more than seven times the outdoor concentration today-and found that their 25 No subjects experienced cognitive impairment or health problems. Only when scientists inject the trace amounts of organic compounds released by other human bodies into the same air will the subjects begin to feel uncomfortable, reporting: “Headache, fatigue, lethargy, and blurred thinking.”
Subjects also spent longer time solving mathematical problems. This same laboratory found in another of their studies that when the concentration of pure carbon dioxide in the room rose to 5000 parts per million, [6] , at least for college students, still caused only a small amount Discomfort.
But other studies are not so optimistic. Scientists at the NASA Johnson Space Center (NASA ’s Johnson Space Center) tested approximately 24 “class astronaut” individuals. They found that the subject ’s advanced decision-making ability decreased at a carbon dioxide concentration of 12,000 parts per million; but the cognitive ability did not seem to decrease much, and the same carbon dioxide concentration had different effects on different people. .
In September 2019, some of the scientists who initiated this issue-including those in the Danish laboratory mentioned above-reviewed all 10 studies on this topic since 2012. On a medium cognitive test, they found the evidence ambiguous: sometimes, higher concentrations of carbon dioxide seem to reduce capacity, and sometimes it has no effect.
But what is more worrying is that they noticed “reliable but still inconsistent evidence.” At moderate concentrations, human performance will decline on special challenging issues. For example, when the carbon dioxide concentration is 1,200 parts per million, the performance of pilots on the aircraft begins to decline. “The mechanism behind the reduced performance is still unknown,” they added.
In other words, the evidence suggests that indoor carbon dioxide levels may hinder only the most complex and challenging human cognitive tasks. We still don’t know why this is so.
In their September review, the author emphasized that many aspects of the problem still need to be explored. For example, does carbon dioxide really damage the brain more than other pollutants? This is still unclear. No one has paid attention to the effect of indoor carbon dioxide on children, the elderly or people with health problems. At the same time, current research only exposes people to extremely high levels of carbon dioxide for only a few hours, and what long-term exposure will bring remains to be explored.
Worries from research
Based on this, obtaining core questions about human cognition is a real challengeWar, Polish professor Gol said.
A unified, reliable, cross-cultural, and widely used human cognitive standard does not exist exactly. This is why some studies use the “decision management simulation tool” (strategic management simulation) [7] —— 一 This method is commonly used in business and medical schools; professionals who study similar pilots will use more specific tools, such as flight simulators. In addition, it is almost impossible to completely control all the factors that affect thinking, such as the quality of someone’s sleep the night before. Most studies are currently very small, testing at most 30 people. He said: “It would be better to operate on a scale of hundreds or thousands of people.”
“The impact on human cognition, unfortunately, I think that science has not yet clarified the direct role of carbon dioxide.” Gore said, “Unless we can prove that carbon dioxide itself is a causative agent, the atmospheric environment is still Can affect the indoor air quality in many ways. “
The most thought-provoking loopholes in the research are also the most worrying. As a race, modern humans have a history of 300,000 years. During most of the evolution of our lives, the external carbon dioxide we are exposed to-from the first breath of a baby to the last breath of a dying old man-is more than today There is much less carbon dioxide outside.
I asked Gore: “Has anyone studied that if at a lower carbon dioxide level, human cognitive ability will improve? If you are in a carbon dioxide concentration of only 250 parts per million Test someone in a room whose level is lower than the concentration of carbon dioxide in the earth ’s atmosphere three centuries or three millennia ago, will their performance improve in the test? “In other words, is it possible that human cognitive ability has deteriorated Anymore? Gower said he did not know about such experiments.
But of course, a larger experiment is in progress, but it does not happen under clinical conditions.