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The bottleneck might be the air in the room

blog.mikebowler.ca

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Re: The bottleneck might be the air in the room

#331

Post by [deleted] »

amluto wrote: post #322
mort96 wrote: post #275

Earlier quoted context omitted.

I would not want to live in a city where I have to be careful letting in outside air or going outside because there's too much air pollution...

Even if you live in an air quality paradise, it’s not ideal for your indoor air to be the air that manages to sneak through all the little cracks in your structure. Especially if you have cold outdoor temperatures, indoor humidity such that the outdoor temperatures are below the indoor dew point, and airflow through the walls that can lead to condensation and possibly mold in those walls. Your indoor air should enter…

[deleted]

Re: The bottleneck might be the air in the room

#332

Post by ShinyLeftPad »

colechristensen wrote: post #311
quickthrowman wrote: post #307

Earlier quoted context omitted.

When was the last time you had that sensor calibrated properly with a can of test gas and a multimeter?

Take it outside, as long as it measures 400-450 it's probably good. Metrology calibration is necessary if you want accuracy better than 10%, but most of us don't care at all about that, instead we care about increments of 200ppm or more.

Local factors can make your CO2 fluctuate by 200ppm. If you're near a busy road with not a lot of wind 600 ppm is possible. But it's not that important if you open your window at 1000 ppm or 1200 ppm.

Re: The bottleneck might be the air in the room

#333

Post by mikestew »

OutOfHere wrote: post #212
Gigachad wrote: post #154

Earlier quoted context omitted.

For the purposes of indoor ventilation monitoring you can calibrate by occasionally exposing the sensor to fresh air. Either taking it outside or just the room not having people in it. The sensor will treat the lowest reading it gets as 400ppm since this is what outdoor air is. A sensor mounted in the office will get calibrated every night when the office is empty.

The outdoor CO2 is rising every year. It is not fixed at 400 ppm. The calibrations you speak of are fake. A good sensor can be expected to remain within 10% of reference for ten years.

The outdoor CO2 is rising every year. It is not fixed at 400 ppm.

But close enough for most purposes. We aren’t doing laboratory measurements here, I just want to know whether or not to open a window.

Re: The bottleneck might be the air in the room

#334

Post by OutOfHere »

quickthrowman wrote: post #312
OutOfHere wrote: post #207

Earlier quoted context omitted.

I disagree. I feel a very steady and progressive deterioration starting at 600 ppm. It becomes significant at 800 ppm. The studies back up the latter threshold.

You would not notice a difference if you weren’t checking the CO2 ppm. You primed your brain to ‘feel’ the effects of higher CO2 by reading a study and are experiencing the nocebo effect. If it makes you feel better I don’t see a problem with it.

Indoor CO2 is likely overrated here at these sub-1000 levels but it's a useful proxy metric for bioeffluent VOCs which are a tiring subset of total VOCs. Ventilation lowers both. This explains the observation better than nocebo theory. See https://www.aivc.org/resource/effects-carbon-dioxide-and-wit...

Re: The bottleneck might be the air in the room

#335

Post by jameshart »

colechristensen wrote: post #311
quickthrowman wrote: post #307

Earlier quoted context omitted.

When was the last time you had that sensor calibrated properly with a can of test gas and a multimeter?

Take it outside, as long as it measures 400-450 it's probably good. Metrology calibration is necessary if you want accuracy better than 10%, but most of us don't care at all about that, instead we care about increments of 200ppm or more.

Haha yes. 400-450ppm is fine. We’re doing just fine here. Everything is okay.

https://www.co2levels.org/

Re: The bottleneck might be the air in the room

#336

Post by aurelwu »

hanspagel wrote: post #76

Not gonna happen in Germany. I don’t think I‘ve ever seen a windowless room here and it’s common to open all windows at once for a few minutes, just to replace as much air as possible: Stoßlüften.

Take a look at indoorco2map.com and you will find plenty of places in Germany with bad air measured in a crowd data collection effort. Most notably doctor‘s offices are often very bad. Many supermarkets too. Schools are not well measurable this way but academic research shows they often are at 2000-3000 ppm or even higher. (Disclaimer: I built the website/App)

Re: The bottleneck might be the air in the room

#337

Post by OutOfHere »

mikestew wrote: post #333
OutOfHere wrote: post #212

Earlier quoted context omitted.

The outdoor CO2 is rising every year. It is not fixed at 400 ppm. The calibrations you speak of are fake. A good sensor can be expected to remain within 10% of reference for ten years.

The outdoor CO2 is rising every year. It is not fixed at 400 ppm. But close enough for most purposes. We aren’t doing laboratory measurements here, I just want to know whether or not to open a window.

You don't need to routinely calibrate a good device at all for that purpose. It already will maintain a reading within 10% of the real value. If it's not doing that, it's a bad device. It's very possible your calibration process will actually miscalibrate it and increase the error. Already the outdoor CO2 level is 430, not 400, so you'd be introducing at least a 7% error by calibrating it to 400.

What I do at home is I have multiple meters bought over the years, not all at once. If one of them is too deviated, I can replace it, but this deviation has never happened in the last five years. It did happen once about ten years ago with an old model.

Re: The bottleneck might be the air in the room

#338

Post by OutOfHere »

teiferer wrote: post #258
OutOfHere wrote: post #207

Earlier quoted context omitted.

I disagree. I feel a very steady and progressive deterioration starting at 600 ppm. It becomes significant at 800 ppm. The studies back up the latter threshold.

Unfortunately it will be hard for you to know how much of that effect is placebo. Unless you tested this with some kind of double-blind setup.

You're not wrong, but indoor CO2 at these sub-1000 levels is a useful proxy metric for bioeffluent VOCs which are an objectively tiring subset of total VOCs. Ventilation lowers both. This explains the observation better than nocebo theory. See https://www.aivc.org/resource/effects-carbon-dioxide-and-wit...

Re: The bottleneck might be the air in the room

#340

Post by OutOfHere »

bob1029 wrote: post #234

I've noticed that cooking with gas is easily the worst thing for CO2 levels. Even with lots of ventilation my kitchen will hover around 1200ppm until it's over with. I swear I can feel the 430ppm already. I was born into a world with 340ppm. I can't imagine what it's going to be like when we hit 500+ globally. I'm in the market for an active CO2 scrubbing solution that I could deploy at home. Scrubbing the entire pla…

Controlling indoor CO2 is important, but it's a proxy metric for the escalation in indoor bioeffluent VOCs which are a tiring subset of total VOCs. This is why scrubbing indoor CO2 will by itself never produce the pro-cognitive result you want. See https://www.aivc.org/resource/effects-carbon-dioxide-and-wit...

Also, when you cook on a gas stove, it produces numerous other toxic gases which too are critical to ventilate before they even escalate, failing which the lung cancer is risked.

Scrubbing indoor CO2 is sensible only when you want to go below the outdoor CO2 level, not at levels above it.

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