Literally Suffocating in Meeting Rooms, A Little
howonlee.github.io
howonlee.github.io
Incidentally, humans can tolerate much higher CO2 levels with accommodation, but, as with altitude, it takes days. The US Navy submarine people have done considerable work on this. So this is not a global warming issue.
Real CO2 sensors are still about US$60 as a part. The standard sensor has a heating element, and uses about 75mA, so this isn't suitable for battery operation. 1mA sensors are now available, but for US$160 or so. This cost problem is holding back widespread use in HVAC systems. HVAC systems for rooms where the people load varies widely (classrooms, offices, hotel function rooms, restaurants) should have a CO2 sensor to tell how much outside air you should be pulling in. But outside of hotels, they're rare.
Cheap "air quality sensors" measure volatile organics, which is something else entirely.
Windows open? Drops into 600ppm range. GF and I at home with closed windows and HVAC off, usually climbs into 1200pm range. Gas oven on? Easy to get over 3000ppm if there's no ventilation on.
> But outside of hotels, they're rare.
I haven't made it a point to look in all of them, but I've seen quite a few in microbreweries in the room they do their brewing. Not sure if required by law, but it's generally a good idea.
The floors of our office that I sit in has two sizes of meeting rooms: one for eight/nine people and one for three people. Free meeting rooms are scarce during regular hours, so sometimes we cram in to three-person room.
It's fun watching the CO2 measurement climb from 800 to 1400. Supposedly 400 ppm is outdoors, 800 ppm is indoors and anything higher is a little unusual. I have fun pointing out the reason why we are all feeling sleepy and docile towards the end of a meeting is because of the CO2!
See also: https://www.nytimes.com/2019/05/06/health/conference-room-ai...
That’s what scares me
This is possibly even a more serious problem in tightly weatherized bedrooms. I was in a rehabbed house tightly weatherized by the contractor (to meet a typical building code). It had radiant heat. When my wife and I sat in the bedroom for 1 hour, a calibrated CO2 sensor showed levels rising to 1600 ppm. (Humans put out lots of CO2). Sleeping 6 - 8 hours in that environment is very likely to cause cognitive impairment the next day. So if you're in a "tight" house, make sure to sleep with the windows open!
Raising the question of course, of why then tightly weatherize the house? Well, so we can say, we're being environmentally responsible, of course!
10% (100000 ppm) concentrations can cause unconsciousness or death even if you have enough oxygen.
It is because we don’t only need to get oxygen from air but also to exhale CO2 as waste. And the higher CO2 partial pressure is the harder it is to get rid of it. Eventually killing us.
The right answer is to switch on your heat-recuperating ventilation.
Instead of spending resources to tighten it, then spending more resources to install a compensating appliance.
Also, just how big are American bedrooms? Mine is 172 sqf and I consider it a big one.
https://en.wikipedia.org/wiki/Crassulacean_acid_metabolism is a decent introduction to it.
Also, most "kid" bedrooms are around 10x10 or so, but some master bedrooms can be rather ... large. I said 3-4 to cover both not being the only one in there and the size of the plants. The tests are done on or projected to full-size mature plants, but if you go to the store and buy them they are rarely full size. They'll range from 6-8" babies to about 1/3-1/2 in size (1-2'). For the "full effect" from the reports they size based on a 4' tall plant.
And only a select few can afford to keep it going all the time.
https://www.revk.uk/2019/03/air-quality-and-co-levels.html
https://www.revk.uk/2019/03/understanding-co2-air-quality-be...
He’s very much an old-school Hacker; it’s worth reading the posts he’s made since those two.
That, and perhaps their street cred as O.G. Hacker. A distant second.
I wonder whether proper air venting through school increases the global IQ and total skills of students.
I heard that other places don’t have toilets, opening windows, or even the opera!
Too bad, they're pretty great.
Not being able to sit by the window and keep it open whenever I need it is yet another thing that I hate about open spaces.
Isn't the latter (when possible) better for cognitive capacities and well-being? and most importantly for the global environment
Having all kind of material to improve locally and artificially the air, like air-conditioning, feels like a temporary hack for a bigger problem, adding even more pollution in the equation
They don't have to fully supply everyone's oxygen to be effective, nor do they have to fully consume your CO2. That said, you'd be surprised at how well some of these will do just that. As a rule of thumb, about four mature sansevieria trificiata will convert as much CO2 to O2 as a single human does on a daily basis. But with those they are storing the CO2 by day and releasing O2 by night so while they will sck up the CO2 in your office by day, you won't see the O2 "come back" in that same time - at least not significantly so.
Others such as some of the palms and lillies, and a few ferns, would do that same "effort" but in the daytime. Even then, in the context of offices and other rooms in this discussion the part to look at is their CO2 consumption, not the production of O2.
Some plants, such as Ficus benjamina are very effective. One (or more) of those with a total leaf surface area of 1 square meter can take a closed room from 2,000ppm CO2 down to 400-500ppm in one hour (variance based on temperature and light levels).
Interesting to think though about the whole co2 thing, if we keep burning fossil fuels we won't be able to think properly anymore?
After reading it I started leaving either a window or a door cracked, but honestly did not notice a difference.