Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

The bottleneck might be the air in the room

blog.mikebowler.ca

Post reply on HN
Print view View original

471–480 of 499 posts

Re: The bottleneck might be the air in the room

#471

Post by jason1cho »

riquito wrote: post #353
Aurornis wrote: post #352

Earlier quoted context omitted.

> I really wish a Apple or another major OEM would integrate CO2 monitor into watches or smartphones CO2 levels are locally elevated in the area where you exhale. Someone sitting at a desk with their hands on a keyboard exhaling through their nose would be producing a directed stream of elevated CO2 straight at the sensor on their wrist. Same thing if someone puts their phone on their desk. Even with the IKEA and oth…

> CO2 levels are locally elevated in the area where you exhale. That's the same area we inhale from... Wouldn't be right to measure there then? It's not like we're interested in the amount of CO2 on the ground (in this discussion)

Exactly!

I installed a CO2 monitor at home, which reminds me of ventilation in winter when I keep windows closed and heating on.

Re: The bottleneck might be the air in the room

#472

Post by zeristor »

I’ve wondered if we can do better, with my Aranet in Spring, and living close to the forest with the windows open on a breezy day my CO₂ reading went down to 410.

I’m guessing if someone had their air go through a conservatory first it could go lower.

In some climate YouTube videos people slip in the CO₂level of when they were born, an interesting point, mine was 325, but I guess there was more lead in the air then…

Is there much of an improvement, impractical as it is, to a far lower CO₂ level.

Re: The bottleneck might be the air in the room

#473

Post by salahadawi »

JonathanRaines wrote: post #420
salahadawi wrote: post #99

Earlier quoted context omitted.

I've actually been tracking the front page of HN for AI posts for a while now: https://www.salahadawi.com/hacker-news-ai-detector This post evaluates to 99% AI generated.

Pangram claims to be super accurate. Do you know how? I understood detection is a hard problem.

Their technical report (arxiv.org/abs/2402.14873) goes into it.

They train a classifier on human text paired with AI-generated versions of the same documents. Dataset scale is comparable to LLM pretraining sets.

Re: The bottleneck might be the air in the room

#474

Post by salahadawi »

jsnell wrote: post #316
salahadawi wrote: post #99

Earlier quoted context omitted.

I've actually been tracking the front page of HN for AI posts for a while now: https://www.salahadawi.com/hacker-news-ai-detector This post evaluates to 99% AI generated.

Nice! Have you considered doing a Show HN for that? That's valuable in at least three different ways: public education, showing that most of the articles are still human-written which can be easy to forget about sometimes, and as an easy way to cross-validate my intuition when flagging something as AI-generated without having to manually run Pangram. I despair a little bit about how many HN voters either seem to want…

Seems someone at HN didn't like my post, tried posting in Show HN but was immediately shadowbanned

Re: The bottleneck might be the air in the room

#475

Post by pavlus »

Yajirobe wrote: post #192

I have a CO2 monitor and I don't understand one thing - it seems that CO2 increases more quickly during summer than during winter. If I close my windows it takes longer to reach 1000 ppm during winter than it does during the summer. I didn't gather concrete data on this but this is just what I eyeballed over the last few years. Does anyone know why could this be the case?

Cold air is more dense, than hot air. In winter the difference between the room air temperature and outdoor air temperature is much bigger, so the density difference is much bigger, making Archimedes force stronger and the airflow stronger as well.

BTW, that's also how stove pipes work - vertical column of air hotter than surrounding accelerates well and creates a strong airflow feeding the fuel. But if the pipe is thermally conductive, that air will cool down and won't flow, for hydrocarbon fuels it can also condensate water, that could extinguish fire underneath it. So, pipes are made insulated enough for strong flow.

Re: The bottleneck might be the air in the room

#476

Post by Ikatza »

stein1946 wrote: post #77
gpt5 wrote: post #6

I really wish a Apple or another major OEM would integrate CO2 monitor into watches or smartphones. Suddenly, everybody would be aware of the CO2 level in the room, get alerts, etc. and the problem will just solve itself. There are so many rooms, classrooms, movie theaters and other places with poor ventilation where you just feel dizzy, or fall asleep, not knowing it was just due to lower oxygen levels in your blood…

> Raising awareness is the only real solution. You'd have to raise awareness on every single person in the room and them sustain pressure to the organization in order to have proper CO2 levels in the room/organization. And then you have to align every other person on every other organization to do this as well and hope for the best. Or, you can do the right thing and have the state introduce regulations

It doesn't work like that. I've been made aware thanks to this post, and tomorrow I'll be placing CO2 sensors in every meeting room in the company I work at, and mandating an open-windows or air-circulating policy above 800ppm.

You don't need to make everybody aware, you just need to make the right people aware.

As for the State... Mine mandates that nobody can use the laptop's keyboard, they must use an external keyboard so the laptops' screens can be risen to eye level.

We have the external keyboards and the risers, and nobody uses them.

The State usually finds the worst and most wasteful solution available. Only fools trust the State to solve their problems.

Re: The bottleneck might be the air in the room

#477

Post by dgellow »

ac29 wrote: post #428
dgellow wrote: post #97

Earlier quoted context omitted.

Thanks for mentioning that, last week I got 2 SwitchBot hub mini, 3 temperature sensors each, for 70€ total, they are really neat. Even put one in our fridge, I didn’t expect the signal to pass but it’s working :) Will look at adding the CO2 monitoring Edit: actually, they only sell them as part of a 6-in-1 device, with a display, and a bunch of other sensors. That feels overkill, I wish they would just sell the CO2…

I have a SwitchBot Meter Pro CO2 that is just temp/humidity/C02. Works well and was inexpensive ($50 or so).

Do you mean that one? https://www.switch-bot.com/products/switchbot-meter-pro-co2-...

I wish they would sell just the CO2 meter, like this one: https://www.switch-bot.com/products/switchbot-indoor-outdoor...

Re: The bottleneck might be the air in the room

#478

Post by tzs »

Aurornis wrote: post #352
gpt5 wrote: post #6

I really wish a Apple or another major OEM would integrate CO2 monitor into watches or smartphones. Suddenly, everybody would be aware of the CO2 level in the room, get alerts, etc. and the problem will just solve itself. There are so many rooms, classrooms, movie theaters and other places with poor ventilation where you just feel dizzy, or fall asleep, not knowing it was just due to lower oxygen levels in your blood…

> I really wish a Apple or another major OEM would integrate CO2 monitor into watches or smartphones CO2 levels are locally elevated in the area where you exhale. Someone sitting at a desk with their hands on a keyboard exhaling through their nose would be producing a directed stream of elevated CO2 straight at the sensor on their wrist. Same thing if someone puts their phone on their desk. Even with the IKEA and oth…

Wouldn’t it still be useful because you could look at changes in the measurement? E.g. if I can’t draw any conclusions when my phone says 800 at the start of a meeting because it might be where I’m breathing, but an hour later in the same place it says 2500 couldn’t I conclude we need to take a break and let the room air out?

Re: The bottleneck might be the air in the room

#479

Post by bjackman »

Gigachad wrote: post #157
bjackman wrote: post #112

Earlier quoted context omitted.

IMO it's something where an intervention is often cheap enough that it's worth it even without great evidence. But also bear in mind that regardless of "are we operating at max effectiveness", OSHA sets a legal limit of 5000ppm in a workplace, and that's about _safety_. This article is talking about keeping levels below 1000 which is a very high standard IMO (still arguably justified given the studies mentioned). But…

It's not even that hard to optimise at home. I've found simply leaving the door open to the rest of the house causes the room CO2 to not elevate much over baseline outdoor readings. Or just opening a window just a crack will rapidly remove all excess co2. The real problem is offices and meeting rooms where you have 10 people in a small box for hours and windows that don't open.

That's interesting coz I found the opposite, at my place to keep the level below 1k I usually have to open a window in the room I'm in, or use a fan.

I live on a noisy street so I don't usually want to do that, if I open a window at the back and keep internal doors open it will stay reasonable but significantly elevated.

So yeah I think the lesson here is you probably need to buy a sensor, different homes are gonna differ.

My home is quite small (probably 80m²) and has literally zero ventilation built in (even in the bathroom!). I live in Switzerland where it's traditional to actively ventilate your home twice a day. But that doesn't do anything for CO2. Also it's such a fucking waste of time lol. Looking forward to moving into a modern building.

Re: The bottleneck might be the air in the room

#480

Post by Gigachad »

bjackman wrote: post #479
Gigachad wrote: post #157

Earlier quoted context omitted.

It's not even that hard to optimise at home. I've found simply leaving the door open to the rest of the house causes the room CO2 to not elevate much over baseline outdoor readings. Or just opening a window just a crack will rapidly remove all excess co2. The real problem is offices and meeting rooms where you have 10 people in a small box for hours and windows that don't open.

That's interesting coz I found the opposite, at my place to keep the level below 1k I usually have to open a window in the room I'm in, or use a fan. I live on a noisy street so I don't usually want to do that, if I open a window at the back and keep internal doors open it will stay reasonable but significantly elevated. So yeah I think the lesson here is you probably need to buy a sensor, different homes are gonna d…

I think it’s just quite windy where I am combined with a not particularly airtight building so opening the window just a crack results in a lot of air blowing in
Post reply on HN