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First clean water, now clean air

finmoorhouse.com

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Re: First clean water, now clean air

#121

Post by aidenn0 »

throw0101a wrote: post #62
miduil wrote: post #10

Earlier quoted context omitted.

I share their sentiment, especially because they are trying to explain the topic for the novice buyer - but I think it oversimplifies the issue and the discussion/benefit of UVGI. UVGI does not create Ozone, some companies even sell certified lamps that will definitively not go into the UV spectrum that can cause Ozone. This is true for UV-C and in the postings mention of new far-UVC LEDs. https://www.uvresources.com…

> I share their sentiment, especially because they are trying to explain the topic for the novice buyer - but I think it oversimplifies the issue and the discussion/benefit of UVGI. Most people probably don't change their air filters often enough at home: I have zero confidence of them maintaining an UVGI (themselves, or wanting to shell out the cash for someone to come in). The best thing to do is circulate air per…

I used to have the air-filter changing forgetfulness problem; I got an online subscription to the filter my furnace takes and now I change it like clockwork.

Re: First clean water, now clean air

#122

Post by robocat »

giraffe_lady wrote: post #74
marcosdumay wrote: post #66

Earlier quoted context omitted.

The covid years were crazy. People kept cleaning everything with all kinds of poison (thank god somebody published early that alcohol at 70% is enough, otherwise I think we would see people dropping dead from too much poison), that was known to be useless by around April 2020, and yet everybody actively refused to talk about indoor ventilation. And most were the same people repeating the "are you for or against scien…

Very cynically I think it was rejected early and high up because it simply would have required a top-down decree that large corporations spend an astounding amount of money for the wellbeing of their workers. As a society we've basically ruled out interventions of that sort by now, and it would establish/reinforce the belief that companies are responsible for the health of their workers. Whereas personal-domain actio…

Less cynically, there were no filtration units or HEPA filters available because demand far outstripped supply. It would be interesting to know how fast production could have been increased (face masks took a while).

Re: First clean water, now clean air

#123

Post by schiffern »

Retric wrote: post #73
schiffern wrote: post #70

Earlier quoted context omitted.

Note that, to minimize pollution from vehicle exhaust, you want to set your air to "recirculate" . Unsurprisingly, the roadway is where vehicle pollution is most concentrated! https://www.latimes.com/science/sciencenow/la-xpm-2013-sep-1... Usually what I do is set it on recirculate, and then every ~10 minutes I periodically "flush" the CO2-laden interior air for a minute or so. Ideally, I'm able to do this "flush" wh…

That works for particulates but not gasses like carbon monoxide. You’re better off having the best filters you can get supplying fresh air constantly rather than constantly recirculating stale air.

Carbon monoxide comes from vehicle exhaust, so the levels are still lower outside cities and off high-traffic roads. I'd rather recirculate my "stored up" clean air vs. pull in CO from the line of cars stopped ahead of me. I just involves being aware of the surroundings.

Ideally a controller would monitor the outside CO/PM and inside CO2 to control the recirculate door.

Re: First clean water, now clean air

#124

Post by MontyCarloHall »

Symmetry wrote: post #89
MontyCarloHall wrote: post #19

If, hypothetically, we dramatically reduced the prevalence of airborne disease, what would the effect on our immune systems be? Some hypothesize that living in too sterile an environment leads to autoimmune diseases, since the immune system is calibrated to a certain baseline level of activity, and will turn on the body if this level is not met by external pathogens.

Our hunter gatherer ancestors living in bands suffered from drastically fewer respiratory diseases than we do, you need a large connected population for something like the flu to survive in a human population in the long term. The issue with sterile environments is about the lack of random bacteria, not human adapted pathogens.

That’s likely true, but our hunter gatherer ancestors also saw way more water and foodborne pathogens, not to mention continual parasitic infections to more than make up for the relative lack of immune system stimulation from a lower level of airborne pathogens.

Re: First clean water, now clean air

#125

Post by kccqzy »

ct0 wrote: post #28
LeonM wrote: post #9

Earlier quoted context omitted.

I don't understand why you are being downvoted, you raise a good point. Based on some HN comment from a while ago I invested in a CO2 meter (they are still quite expensive for some reason). And I share the same experience, CO2 levels can raise rapidly indoors, but simply turning on ventilation or opening a window very quickly lowers CO2 contents. Using the meter I found CO2 levels in my bedroom can become quite high…

I'm starting to think that having a better night's rest while sleeping in a tent is not from the ground you sleep on, but the fresh air you've had all night.

My best sleep was on a camping trip when we decided that a tent wasn't necessary and we could just sleep outside watching the night sky.

(This is of course highly location dependent. Now that I think about it, I was probably taking a bit more risk at that time than what I tolerate now.)

Re: First clean water, now clean air

#126

Post by kccqzy »

sergioisidoro wrote: post #2

I bought a CO2 monitor, and although the effects of CO2 in cognition and energy levels are debatable[1], it shocked me and raised awareness to how poor my indoor ventilation is. We live in a small apartment, and just being 30 min with 2 people in the room raises the CO2 ppm from 400 to >1000. Opening a window quickly lowers it. Never-mind doing some light activity like yoga or similar. So if we want to do something,…

This is of course also the reason why I don't like most office buildings. They don't have operable windows and rely on centrally managed HVAC. They sometimes have CO2 sensors but the system is too opaque for occupants to figure out at which level the mechanical ventilation starts.

Re: First clean water, now clean air

#127

Post by mlsu »

radlad wrote: post #91
bsenftner wrote: post #23

Earlier quoted context omitted.

In Japan, it is common to see CO₂ monitor displays outside contained meeting spaces, such as theaters. My wife purchased an Aronet CO₂ monitor, and I took it with me on a business trip last week. The CO₂ while on the flight was in the 3000's range. The CO₂ at my client's office was in the mid 2000's range, as well as the hotel. Opening the hotel window the allowed 2 inches reduces CO₂ to the 600 range in 10 minutes,…

> The CO₂ while on the flight was in the 3000's range. I always assumed they intentionally messed with oxygen in the cabin to "relax" travelers. Anecdotally, I have often experienced a sedative effect on airplanes that I do not ever experience in land vehicles.

In general, anecdotes about "they raise the oxygen levels in [x] to induce [y]" are completely false. I've heard this about airplanes and casinos.

For one, it's really difficult/energy intensive to increase the level of oxygen in a space. Second, it's very very difficult to purify oxygen -- because oxygen oxidizes stuff. Even if you could do that, raising the level of oxygen is extremely dangerous, because it radically increases flammability of things and makes fire much worse. For an example of this: Apollo 1.

Re: First clean water, now clean air

#128

Post by cameldrv »

giraffe_lady wrote: post #74
marcosdumay wrote: post #66

Earlier quoted context omitted.

The covid years were crazy. People kept cleaning everything with all kinds of poison (thank god somebody published early that alcohol at 70% is enough, otherwise I think we would see people dropping dead from too much poison), that was known to be useless by around April 2020, and yet everybody actively refused to talk about indoor ventilation. And most were the same people repeating the "are you for or against scien…

Very cynically I think it was rejected early and high up because it simply would have required a top-down decree that large corporations spend an astounding amount of money for the wellbeing of their workers. As a society we've basically ruled out interventions of that sort by now, and it would establish/reinforce the belief that companies are responsible for the health of their workers. Whereas personal-domain actio…

I think it was a combination of things.

1. Inertia: Sanitizing and disinfection was what was recommended in March 2020. Even masking was actively discouraged until later.

2. "We have to do something." "This is something."

3. Handwashing/hand sanitizing and sanitizing surfaces are visible actions that reassure some people. Ventilation and filtration improvements are generally not visible.

4. Ventilation and filtration improvements are expensive and, for an institution, require certified professionals to design and implement. There aren't enough of these people and not enough equipment to implement this for every building in a timely manner. Handwashing and clorox wipes are cheap and anyone can use them.

Personally I think that COVID is likely going to be with us for some time to come and will cause significant disability as people get infected repeatedly. I think eventually we will see significant uptake of ventilation/filtration improvements.

Re: First clean water, now clean air

#129

Post by Retric »

schiffern wrote: post #123
Retric wrote: post #73

Earlier quoted context omitted.

That works for particulates but not gasses like carbon monoxide. You’re better off having the best filters you can get supplying fresh air constantly rather than constantly recirculating stale air.

Carbon monoxide comes from vehicle exhaust, so the levels are still lower outside cities and off high-traffic roads. I'd rather recirculate my "stored up" clean air vs. pull in CO from the line of cars stopped ahead of me. I just involves being aware of the surroundings. Ideally a controller would monitor the outside CO/PM and inside CO2 to control the recirculate door.

Location is generally less important than wind direction here, which you aren’t tracking.

Having a few internal and external sensors for various gasses could work, but it’s a surprisingly difficult problem.

Re: First clean water, now clean air

#130

Post by lukevp »

sizzle wrote: post #108
schiffern wrote: post #70

Earlier quoted context omitted.

Note that, to minimize pollution from vehicle exhaust, you want to set your air to "recirculate" . Unsurprisingly, the roadway is where vehicle pollution is most concentrated! https://www.latimes.com/science/sciencenow/la-xpm-2013-sep-1... Usually what I do is set it on recirculate, and then every ~10 minutes I periodically "flush" the CO2-laden interior air for a minute or so. Ideally, I'm able to do this "flush" wh…

I always crack my sunroof an inch and pull the shade forward go get some fresh air in recirculate mode so I’m not picking up crap from the engine bay. How does the fresh air mode on the car not pull in CO gases from the engine bay? Surely a pleated cabin filter is not enough to stop it? Or does the air come from the manifold air intake?

The air intake in the grille is only for the engine’s use. The fresh air intake is not in the engine bay, it’s typically at the base of the windshield.
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