Talks to Watch

This Is Your Brain On Stale Air

4.2M views · Jan 21, 2019 · 5:51 · 2 HN recommenders · 13 mentions · discussed 2019–2025

Tom Scott features Kurtis Baute inside a sealed homemade biodome as carbon dioxide builds up, showing how stale air with elevated CO2 affects cognitive function. Sources include studies on CO2 and cognitive scores.

Why Hacker News points people here: HN links it as a popular, accessible introduction to indoor CO2 and its effect on thinking, in air quality threads.

“Tom Scott did a great video on it a while back”HN comment, 2020

What Hacker News said 13

RecommendsyoodenvranxJan 2019

“it's a good palce to start research”

Good starting point for researching CO2 effects.

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For those who are wondering about 'changed my life': Tom Scott uploaded a video about CO2 and its influences a few days ago. it's a good palce to start research: this video

in “Show HN: I wanted to measure CO2 in my office, so I build a C++ WebServer/App” · view on HN
Recommendswh-uwsMay 2020

“Tom Scott did a great video on it a while back”

Shows CO2 effects on cognition.

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This one of those things that sounds silly but is actually very easy to test and see it can be a real issue. Tom Scott did a great video on it a while back this video Do yourself a favor and get an air quality monitor like an awair link and monitor the levels. Making sure they are good in whatever indoor areas you spend a good amount of time in is a night and day difference cognitively.

in “Rising CO2 levels may trigger cognitive impairment, says new study” · view on HN
Cites ityoodenvranxJan 2019

“Tom Scott uploaded a video about CO2 and its influences”

Tom Scott video on CO2 and its influence.

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Is it just coincidence that Tom Scott uploaded a video about CO2 and its influences at almost the exact time the gwerns link was submitted? this video

in “On whether changes in bedroom CO2 levels affect sleep quality” · view on HN
Cites itdigitalsushiJan 2019

“wherein a person sits in a sealed off cube full of plants and carbon dioxide monitors”

Person sits in a sealed cube with plants and CO2 monitors.

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Floating around this week is this video this video wherein a person sits in a sealed off cube full of plants and carbon dioxide monitors, with an EMT on the other side for safety - the person claims that 300 ppm of outside air was fresh, and now 400 ppm is fresh - but that indoors, it can easily climb to over 1000ppm and that there might be a significant cognitive decline associated with it. I was looking for a nice wall receptacle for a hallways that measures carbon dioxide inside my house because I will go for weeks at a time without getting a proper air-out. In northern new england, honestly, it could be months for all I know. Only a few random door openings and the leakiness of the house are my exchange. I don't know how accurate their claim is, and it's certainly a universal solvent to consider stale air is the reason a person is behaving a way. Measuring the levels and being aware of it seems worth 60 bucks, if it's actually a factor in our rationality.

in “Researchers develop a new houseplant that can clean home air (2018)” · view on HN
Cites itbemmuJan 2019

“Higher ppm decreases cognitive function even at pretty low levels”

Cites a cognitive decline figure for 1000ppm CO2.

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Higher ppm decreases cognitive function even at pretty low levels, so being alerted to open your window might improve your work / study. There's at least this study: link And this video has the quote "At 1000ppm there is a 15% decrease in cognitive function". this video

in “Show HN: I wanted to measure CO2 in my office, so I build a C++ WebServer/App” · view on HN
Cites itstackmadJan 2019

“the body is pretty bad at recognizing higher than norm CO2 level unless it gets to life threatening levels”

Body poorly senses elevated CO2.

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Its not that I'm afraid to die here :) Its more about improving the quality of the air. And the body is pretty bad at recognizing higher than norm CO2 level unless it gets to life threatening levels. ( this video )

in “Show HN: I wanted to measure CO2 in my office, so I build a C++ WebServer/App” · view on HN
Cites ittechiferousNov 2019

“After watching this Tom Scott video”

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After watching this Tom Scott video this video I bought this CO2 monitor: link It worked quite well and showed that I don't have anything to worry about. Now I'm trying to pass it on to someone else. I'll be willing to sell it for half price if anyone is interested.

in “The cognitive costs of air pollution” · view on HN
Cites itdarkmightyNov 2019

“Obligatory Tom Scott video on indoor CO2 levels”

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Obligatory Tom Scott video on indoor CO2 levels: this video (or the studies themselves link and others) I.e. I think air quality is likely a big factor. When it's windy and I get good airflow through my room it doesn't feel as different from outside. It's probably not only CO2, but also dust, VOCs, funghi, microorganisms, etc.

in “Rooms can be as bright as the outdoors” · view on HN
Cites itderefrMar 2020
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I’ve lived in a lot of places in my life, and spent at least some time in seclusion in each one. And I have experienced the “cabin fever” feeling before... but not everywhere I’ve lived. In some environments, it happened easily and immediately; in others, it never did. I’ve tried to think about my environment at each juncture to figure out if the situations where I did experience “cabin fever” had anything in common. Every time I experienced the symptoms described in the article (restlessness, lightheadedness, insomnia, irritability, etc.) I was living in a modern, rather-well-sealed apartment building; or was on a long road-trip in a modern, rather-well-sealed car; or was on a long plane flight; or was staying in a modern hotel room in a high-rise; or I was camping in a tent or camper-trailer. Meanwhile, I’ve never experienced these symptoms while living in an old, drafty brick building (repurposed office building); or while living in a Victorian-era farmhouse; or while staying in a low-rent motel; or while camping under the stars. My conclusion is that “cabin fever” is a feeling you get when your living space is not well-ventilated. Specifically, when there’s no way to create a through-draft of air, so even opening windows won’t force out the air deeper in the home—leading to that air becoming stale, creating a built-up “cloud” of CO2, other gaseous bodily wastes, and exhaled aerosolized water droplets (you know, those things that viruses travel on.) It happens faster when

Cites itthamerJul 2022

“For a more pop-sci take on this, see this Tom Scott video”

Subject in airtight chamber shows brain function impact as CO2 rises.

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Covid aside, a reading of almost 6000 ppm in the bus is extremely high, at this level there is a clear impact on cognitive function. See this study[1] in Nature that measured the effects of CO2 at 1000, 3000, and 5000 PPM. Quote: "For the Psychomotor Vigilance Test, the probability of achieving an accuracy score of >90% decreased in a dose–response like fashion from 79.5%, 74.7%, 73.4%, to 64.0% for 600, 1200, 2400, and 5000 ppm, respectively". Another study[2] tried to establish the effect on response time, finding that "For every 500ppm increase, we saw response times 1.4-1.8% slower, and 2.1-2.4% lower throughput." For a more pop-sci take on this, see this Tom Scott video where a subject is placed inside of an airtight chamber where the CO2 gradually increases, with a major impact on their brain function: this video [1] link [2] link

in “Whose breath are you breathing?” · view on HN
Cites itjobigoudNov 2022

“It was featured in a Tom Scott video”

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Kurtis Baute tried to seal himself in a greenhouse with plants and that wasn't enough to compensate the exhaling. It was featured in a Tom Scott video: this video

in “Analyzing Carbon Dioxide levels while attending IETF-115 in London, UK” · view on HN
Cites itM3L0NM4NJan 2023

“Higher levels of CO2 result in less brain function, as shown by this Tom Scott video”

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I will note though, CO2 measure indoors can be very valuable. Higher levels of CO2 result in less brain function, as shown by this Tom Scott video: this video

in “AirGradient Open Source Air Quality Monitor for CO2 and PM2.5 Measurements” · view on HN
Cites itjackcurranAug 2025

“here are some cool links that I've heard people say completely changed their thinking about air quality”

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Here is our Kickstarter Project Link. We'd love your support! My best friend and I have spent the past year trying to track the environment in our NYC apartments, cafés, and subway cars. We tried the usual handheld monitors and bulky bricks, but none were truly pocket‑friendly, user friendly, and most importantly, they only tracked a single metric, and poorly at that. So we built our own. Made it a powerhouse of multiple sensors. And miniatured it to fit in your pocket when you want to put it away. Our device (named Halo Air after our favorite game, Halo 3) snaps to the back of any smartphone and streams CO₂, PM1/2.5/10, t‑VOCs, temp, and humidity into our app, a lockscreen widget, and we'll be making the data feed available too. No disposable batteries, no calibration stickers—just one USB‑C charge and go. We just hit Kickstarter yesterday. If you’re curious, we’d love your feedback (good, bad, brutal) and—if it resonates—your support as early backers. The link’s in the first comment to avoid spamming the post. Huge thanks to Reddit for the inspiration threads on sensor accuracy, cross‑calibration, and DIY enclosures; your collective brainpower shaped Halo Air more than you know. If you're interested in the area, here are some cool links that I've heard people say completely changed their thinking about air quality: This Is Your Brain On Stale Air (Youtube) this video Elon's X thread about his CO2 Monitor: link Diary of a CEO: The Air In Your Room Is Making You Stupid & Harmi