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First clean water, now clean air

finmoorhouse.com

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Re: First clean water, now clean air

#71

Post by adolph »

mensetmanusman wrote: post #32
adolph wrote: post #7

Earlier quoted context omitted.

That is an interesting explanation. I won’t summarize other than to say that as someone who might have added UV next hardware cycle, there were several A-Ha moments. Well worth watching.

UV is more than UV, there is UVA UVB UVC, etc. Some UVC generates Ozone, some do not. Wavelength and spectral Q factor matter. It’s possible to have a UV system that does what you want without the downside, but it does cost.

One of the critical points to the video is that in order to prevent bad side effects of UV, a deployment is not only costly on the front end but also costly in ongoing maintenance. In addition to UV, there is also a hazard of high voltage induced ozone.

My overall impression is that it isn’t a technology at a consumer grade maturity.

Re: First clean water, now clean air

#72

Post by Retric »

blkhawk wrote: post #61
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,…

I have had a self-build CO2 monitor for several years now and I find the airplane example Surprising. AFAIK the air in a Plane is cycled out too fast for that amount to develop. Maybe the Lower air pressure was the cause? Since it was portable it was probably the NIR type? If its not measuring all the time it might also be the heater type - I am really not sure how that type would deal with low pressure. Or was is th…

Local passenger density is going to play a role here venting air from low density first class areas isn’t going to do much. Similarly as you mention air flow is important as being in the middle of a large row could have vastly worse airflow than other areas.

So, I could easily see the aircraft venting mostly 700ppm air while some areas hit 3000 ppm internally.

Re: First clean water, now clean air

#73

Post by Retric »

schiffern wrote: post #70
bsenftner wrote: post #56

Earlier quoted context omitted.

Opening a car window or running air not on recirc immediately drops the readings to safe levels. I also noticed when in the Uber returning from the airport, the air was in the high 3000's and I explained to the driver, he opened all the windows and I think I scared him a bit.

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.

Re: First clean water, now clean air

#74

Post by giraffe_lady »

marcosdumay wrote: post #66
giraffe_lady wrote: post #42

Earlier quoted context omitted.

No, there won't be any battle. If there were going to it would have been during covid, with improved indoor ventilation being one of the major components of an in-depth mitigation strategy. There was no meaningful attempt or debate about changing ventilation standards then when it would have tangibly saved lives, there certainly won't be now.

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 actions like sanitizing and masking cost companies basically nothing and reinforce the mindset that covid mitigation is an individual responsibility and so the consequences from having it are an individual burden. It doesn't even matter if they work or not, from this perspective, which explains why pointless things like sanitizing and QR menus persisted so long.

Re: First clean water, now clean air

#75

Post by sidewndr46 »

scythe wrote: post #68
throw0101a wrote: post #62

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. 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 work in medical physics. The issue of ozone generation from ionizing radiation has come up from time to time. In radio/fluoro rooms, it's basically undetectable. In radiotherapy, it might reach the odor threshold after long treatments, but this is rare. These are systems that produce radiation way beyond the energies that can create ozone via UVC. The ozone level is barely measurable and not considered a serious ri…

you don't have to have arcing in the device. Coronal discharge is the normal way to create ozone.

Re: First clean water, now clean air

#76

Post by BizarroLand »

Cthulhu_ wrote: post #37
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,…

It's a tradeoff, because good ventilation - ideally just open a window - also means heat is leaking out of the house, which costs money (and co2 emissions) to restore. There's cyclic systems, but I live in a neighbourhood where some houses were equipped with it; on the proper setting, it was too loud so people turned it down, then people got sick from high CO2 levels in their house.

There are ERV and HRV systems that will cycle fresh air in while exchanging the heat and moisture from the outgoing air to the incoming air.

It's a neat technology but the jury is still out on it.

Some people praise them, other people revile them, and they seem to be either too bulky or too cumbersome or too expensive or too inefficient for a DIY retrofit project.

Re: First clean water, now clean air

#77

Post by BizarroLand »

Abekkus wrote: post #35
sbaiddn wrote: post #15

Earlier quoted context omitted.

That's why I'm not changing my very leaky and drafty windows - I don't want to live in a hermetically sealed Tupperware container. Once I install an HRV system then I'll do the windows!

Or you could save $2k on materials & labor, and put in a filtered vent fan. You only need around 15CFM per resident. Household HRVs & ERVs have suspiciously low heat efficiencies for their costs.

85-95% isn't suspiciously low.

Where are you getting this information from?

Re: First clean water, now clean air

#78

Post by anonymouskimmer »

marcosdumay wrote: post #66
giraffe_lady wrote: post #42

Earlier quoted context omitted.

No, there won't be any battle. If there were going to it would have been during covid, with improved indoor ventilation being one of the major components of an in-depth mitigation strategy. There was no meaningful attempt or debate about changing ventilation standards then when it would have tangibly saved lives, there certainly won't be now.

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…

> otherwise I think we would see people dropping dead from too much poison

At least one person (with multiple chemical sensitivity) committed suicide (medically-assisted) because the sanitation and smoking in her apartment complex during COVID made her life so miserable she didn't want to live anymore. https://www.ctvnews.ca/health/woman-with-chemical-sensitivit...

Re: First clean water, now clean air

#79

Post by fatuna »

clairity wrote: post #47
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,…

> "although the effects of CO2 in cognition and energy levels are debatable" it's really not debatable. the feeling of stuffiness is a function of many things, but environmentally, it's mostly temperature and humidity (we humans are hot and breathe out lots of humidity). there are no cognitive/energy effects until you get into the 10's of thousand of ppm, as the mechanism of action is competing out oxygen, not some i…

Do you have any sources on this? I'm keen to know more, but googling results in either very dry researchpapers or ads on either co2 meters or air purifiers.

Re: First clean water, now clean air

#80

Post by clairity »

sergioisidoro wrote: post #63
clairity wrote: post #47

Earlier quoted context omitted.

> "although the effects of CO2 in cognition and energy levels are debatable" it's really not debatable. the feeling of stuffiness is a function of many things, but environmentally, it's mostly temperature and humidity (we humans are hot and breathe out lots of humidity). there are no cognitive/energy effects until you get into the 10's of thousand of ppm, as the mechanism of action is competing out oxygen, not some i…

Yes they are debatable. There are cognitive performance tests that show statistically significant decline in many tasks above 1500ppm, especially on planning tasks. That's independently of the feeling of "stuffiness". If these measurable declines have a sufficient impact on our lives and productivity is the debatable part. Edit: here's one reference: "We also found effects of CO2 (a proxy for ventilation) on cognitiv…

if you look at the paper, you see no such conclusive evidence, but rather weak correlative assertions in noisy and complex environments. also notice the incentives and implicit bias of the involved. unbiased studies from the past several decades have so far shown cognitive effects require 10× that level of CO₂ to show any conclusive effects. even the pm2.5 effects attempt to make a short-term correlation, which is dubious at best. long-term pm2.5 effects are more conclusive, which is why we should be more concerned about them.

CO₂ is a fashionable concern but not scientifically supported. more importantly, it distracts from things we really should be concerned about as states and nations, like actual pollution and the alarming concentration of power and wealth.

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