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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

#441

Post by jerlam »

josephg wrote: post #295
throw0101a wrote: post #217

Earlier quoted context omitted.

> 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. Not wrong, but it is perhaps worth noting that there are already standards for proper ventilation. Generally you're looking at 5–10 cfm/person (2.5-5 L/s), depending on the…

Should… Whenever I travel, I bring a CO2 meter with me. It’s amazing how often the air is bad. Often in unexpected places. My meter hit 3100 in an uber once. I didn’t even notice until I got to my hotel room and looked at the data log. It was a fresh, hot day outside. The uber had windows closed and AC on. I bet he had no idea - but he was driving with significant cognitive impairment. Takeoff and landing in planes a…

Cars have a "make the air bad" button, the recirculation button. Some people always have it on. I wonder if it's a factor in road rage.

Re: The bottleneck might be the air in the room

#442

Post by youarenaive343 »

jameshart wrote: post #377
jaapz wrote: post #351

Earlier quoted context omitted.

The comment was about the accuracy of the sensor, not about raising CO2 levels across the globe.

Sure. It just draws attention to the fact that a throwaway piece of advice for checking calibration of a CO2 sensor is ‘it should read 400-450ppm outside’ when a few short decades ago that advice would have been ‘it should read 300-350ppm outside’. It’s like if someone said ‘you can check if your chatbot’s news feed is complete and up to date by asking it for ‘recent mass shootings’. There should be two or three in t…

[flagged]

Re: The bottleneck might be the air in the room

#444

Post by colinsane »

any tips for calibrating or even just validating these handheld CO2 meters?

i've taken a few Amazon-listed CO2 meters from $dirt-cheap to $150, tossed them in a ziplock, and then discharged CO2 from a canister into the bag & sealed it. none of them read notably differently after an hour, nor show any sort of range error, etc.

i've also done this without the ziplock: put them in a large pot, fill that with CO2. CO2's heavier than the rest of the air so the concentration should remain elevated within the pot, but same deal.

i like the idea of monitoring CO2, but it's hard enough to get certainty about the _effects_ of CO2 level; without confidence in my meter i fear the conclusions i draw from it are more noise than signal.

Re: The bottleneck might be the air in the room

#445

Post by popalchemist »

Aurornis wrote: post #356
riquito wrote: post #353

Earlier quoted context omitted.

> 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)

No, because the studies that establish the levels correlated with cognitive changes use ambient CO2 levels. Not with a stream of air directed, maybe, from your nose to your wrist. It is not possible to come up with a different baseline for wrist-worn monitors because the measurements could change significantly based on even small factors like the position of the wrist or smartphone.

Presumably after a month or so of being worn during the day and taken off at night (when the breathing doesn't apply -- and the device knows this), the device could deduce what the influence of the wearer is.

Re: The bottleneck might be the air in the room

#446

Post by amelius »

mrgyro wrote: post #358
amelius wrote: post #286

Earlier quoted context omitted.

I think the thread established that CO2 sensors are too bulky for that.

So were most other sensors before Apple (and their suppliers) miniaturised the sensors. Gps and imu was huge in the 90s, several pound each.

But this is wishful thinking.

Re: The bottleneck might be the air in the room

#447

Post by hansvm »

Aurornis wrote: post #356
riquito wrote: post #353

Earlier quoted context omitted.

> 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)

No, because the studies that establish the levels correlated with cognitive changes use ambient CO2 levels. Not with a stream of air directed, maybe, from your nose to your wrist. It is not possible to come up with a different baseline for wrist-worn monitors because the measurements could change significantly based on even small factors like the position of the wrist or smartphone.

That makes sense to me. There's a causal link between ambient air CO2 levels and cognitive changes, but the air in front of your face, which you breathe, doesn't play a role...

A lack of direct study might make "in front of your face" numbers harder to interpret in absolutes, but relatively speaking I do think that's the number which matters more. Whole-room analysis is just a proxy for the air in front of your face.

Re: The bottleneck might be the air in the room

#448

Post by hansvm »

josephg wrote: post #295
throw0101a wrote: post #217

Earlier quoted context omitted.

> 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. Not wrong, but it is perhaps worth noting that there are already standards for proper ventilation. Generally you're looking at 5–10 cfm/person (2.5-5 L/s), depending on the…

Should… Whenever I travel, I bring a CO2 meter with me. It’s amazing how often the air is bad. Often in unexpected places. My meter hit 3100 in an uber once. I didn’t even notice until I got to my hotel room and looked at the data log. It was a fresh, hot day outside. The uber had windows closed and AC on. I bet he had no idea - but he was driving with significant cognitive impairment. Takeoff and landing in planes a…

Interesting. I can barely stay awake in typical commercial planes, and I always attributed it to the lower partial oxygen pressure.

Re: The bottleneck might be the air in the room

#449

Post by [deleted] »

embedding-shape wrote: post #78
odiroot wrote: post #70

Earlier quoted context omitted.

Can it work with Zigbee network or is Matter/Thread required?

I'm using a bunch of IKEA's "smart home" stuff, all via Zigbee+HA, works great. Look for the Zigbee icon on the package, and the pairing for Zigbee vs their own home controller might have slightly different pairing sequence on the device, otherwise it just seems to work.

[deleted]

Re: The bottleneck might be the air in the room

#450

Post by jameshart »

youarenaive343 wrote: post #442
jameshart wrote: post #377

Earlier quoted context omitted.

Sure. It just draws attention to the fact that a throwaway piece of advice for checking calibration of a CO2 sensor is ‘it should read 400-450ppm outside’ when a few short decades ago that advice would have been ‘it should read 300-350ppm outside’. It’s like if someone said ‘you can check if your chatbot’s news feed is complete and up to date by asking it for ‘recent mass shootings’. There should be two or three in t…

[flagged]

If faster plant growth were the only side effect you might have a point here.

Boy, it sure has been hot this month, though.

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