[HN Gopher] First clean water, now clean air ___________________________________________________________________ First clean water, now clean air Author : finm Score : 248 points Date : 2023-05-01 09:32 UTC (13 hours ago) (HTM) web link (finmoorhouse.com) (TXT) w3m dump (finmoorhouse.com) | ZeroGravitas wrote: | It doesn't take away from the general thrust of the post but it's | interesting that lack of quality sewage treatment leading to it | being dumped into rivers is thought to be a key issue in the | current British council voting: | | Local elections 2023: How sewage topped the political agenda | | https://www.bbc.co.uk/news/uk-politics-65190097 | makomk wrote: | The Victorian-era sewage systems described in this article are | actually one of the key reasons that sewage is ending up in | rivers and the sea in the first place. Notice how they worked: | sewage was collected, pumped, and dumped downstream of London. | It was not treated. Most of the UK's sewage treatment is | retrofitted to sewage systems that were never designed to have | it. This causes various problems, the main one being that | rainwater drainage and sewage are mixed in many areas and this | overwhelms the sewage system during heavy rain. | | (As for why it became a key election issue, well, basically the | British press lied to make it one - the BBC included. They made | an increase in monitoring of sewage discharges look like a | massive increase in sewage discharged whilst tricking people | into thinking monitoring had got worse by deceptively-worded | articles about the few overflows that weren't monitored yet, | they told people the Environmental Agency was lying about only | recently being able to measure the full extent of sewage | discharges based on a hnadful of previously-recorded incidents, | they claimed other European countries which still had | Victorian-esque sewage systems with no treatment plants that | just pumped directly into their rivers and seas in some urban | areas were doing a better job, and so on.) | brianmcc wrote: | It also seems another Brexit issue - treatment chemicals | being that bit harder to bring in: | | https://www.thelondoneconomic.com/news/brexit-to-blame- | for-u... | Mvandenbergh wrote: | Not in practice, no. Companies were provided with a | regulatory position statement from the EA that they would | not usually be prosecuted if they ran out of treatment | chemicals due to something that wasn't their fault. In | fact, there never was a shortage due to either Brexit, | Covid or a combo and this was never used. | Mvandenbergh wrote: | To be fair, while all of those things are true (and in fact | the poor state of many rivers is more due to farming and to | fully consented but still high-nitrate effluents from waste | water treatment than to CSOs) the industry has really not | even bothered to defend itself here. It's like they're just | cowed by the criticism. | lazide wrote: | Or will get paid to clean it up, so why try to stop it? | vondur wrote: | I wish more of the funds that were allocated to combat Covid were | used to install better air handling systems in public areas here | in the US. The education side received billions of dollars, which | if used for better air would help keep kids more kids from | getting sick and then bringing it home to families. | kazanz wrote: | As others of posted the big difference here - and also the big | challenge - is that indoor air is a definitively NOT a public | service. | | It requires a slew of regulation, enforcement bodies, and - from | a US perspective - profitability for litigation attorneys. | | Again with a US slant, ADA is the obvious legislative model for | similar clean air regulations. | | So it's possible, just more challenging than public sewage. | xmdx wrote: | Other than the obvious benefits like avoiding a pandemic this | hits close to home. My dad passed away 2 weeks ago from Pulmanory | Fibrosis. A respiratory disease without a cure and one where we | know very little about the causes. Better air quality would drop | cases, relive strain on the health system and just let people | live longer. Its something I want to help with where I can. I | hadn't even thought about the obvious step of raising awareness | about air quality. | throw0101b wrote: | > _Ultraviolet germicidal irradiation (UVGI)_ | | Please do not do/use this. | | Generally anything that is 'active', like UV lamps or ozone | emitters, is not a good idea: | | * https://www.youtube.com/watch?v=hSFQQpgvgeo&t=6m1s | | * Interviewee: https://civmin.utoronto.ca/home/about- | us/directory/professor... | | All that's needed for good indoor air quality (IAQ) is an ERV/HRV | which exhausts stale indoor air and brings in fresh outdoor air | (through a filter). | | For comfort you want a furnace+AC/heatpupmp and a dehumidifier. | | And try to make the enclosure as air-tight as possible so the air | comes in and out on your terms and not 'randomly' through cracks | (where it can carry dust and pollen, and bugs can perhaps get | through as well). | miduil wrote: | 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/the-ultraviolet-germicidal-irrad... | | For personal homes UVGI is most likely not needed, unless | immunocompromised I'd guess. For hospitals, pharmacies, | schools, airplanes and other high risk institutions I would | guess that this could prevent plenty of deaths. | | Edit: Their criticism is about the high-voltage needed for | Mercury-vapor UV-C lamps. This can leak ozone, also if the | glass is not filtering the 185nm wavelength properly that will | contribute even further. The article talks about LEDs which | will definitively not leak into this range. Also as far as I | know the specific wavelength of pressure-lamps is not input- | frequency defined as implied by the interviewed guy - not | exactly sure what he's referring to. My takeout would be only | buy mercury-pressure lamps from trusted sources with proper | certifications in place. | throw0101a wrote: | > _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 ASHRAE- | recommendations and get high-MERV filters (and hope they are | swapped regularly). | scythe wrote: | 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 risk. In the | video you linked, the narrator opens by saying that ozone | barely even makes it through the ventilation system, which | is consistent with my understanding of ozone: a reactive, | unstable gas. And Dr. Siegel emphasizes this as well: O3 | doesn't stick around easily. He doesn't seem to share the | presenter's obsession with ozone. | | Frankly, I found the video tedious and gave up after a | minute. Also, the Siegel's background is mechanical | engineering, and he's obviously hedging his statements. | Here's an actual scientific review of O3 generation by | lamps: | | https://onlinelibrary.wiley.com/doi/full/10.1111/php.13391 | | Critical quote: "Again, soft glass UV-C lamps cannot | generate ozone". | | >I have zero confidence of them maintaining an UVGI | | An unmaintained mercury-vapor lamp will not suddenly | violate the laws of physics by emitting radiation below the | 254 nm spectral line of mercury. The only mechanism that | would alter the ozone generation rate is electrical arcing | outside the device, which is really a concern with any | electrical equipment and not specific to Hg lamps. | | Frankly, most of your posts on this sound like you watch | too many videos and don't read enough. "Performing | chemistry experiments on yourself" -- really? This stuff | has been studied for centuries. | | A more realistic concern with UVGI is that they don't kill | everything and can't replace other ventilation components. | Some microbes are very, very radioresistant and you're just | not going to deliver 10 kilogray in a continuous flow duct | using reasonable levels of power. | sidewndr46 wrote: | you don't have to have arcing in the device. Coronal | discharge is the normal way to create ozone. | aidenn0 wrote: | 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. | anecdotal1 wrote: | Reme Halo is what you want. That's what I put in when I | installed my ERV. | | Reme uses UV against titanium dioxide which releases airborne | peroxides which takes out bacteria/viruses/yeast/mold | | This is the same tech used in self-cleaning concrete -- just | add titanium dioxide and let the sun do the work | throw0101a wrote: | > _Reme Halo is what you want. That 's what I put in when I | installed my ERV._ | | Please view the video. The interviewee: | | > _Jeffrey Siegel, Ph.D., is Professor of Civil Engineering | at the University of Toronto and a member of the university's | Building Engineering Research Group. He holds joint | appointments at the Dalla Lana School of Public Health and | the Department of Physical & Environmental Sciences. He holds | an M.S. and Ph.D. in Mechanical Engineering from the | University of California, Berkeley as well as a B.Sc. from | Swarthmore College. He is fellow of ASHRAE and a member of | the Academy of Fellows of ISIAQ. His research interests | including healthy and sustainable buildings, ventilation and | indoor air quality in residential and commercial buildings, | control of indoor particulate matter, the indoor microbiome, | and moisture interactions with indoor chemistry and biology. | Dr. Siegel is an active member of ISIAQ and ASHRAE and was an | associate editor for the journal Building and Environment | from 2014-2018. He teaches courses in indoor air quality, | sustainable buildings, and sustainable energy systems. Prior | to his position at the University of Toronto, Dr. Siegel was | an Associate Professor at the University of Texas._ | | * https://civmin.utoronto.ca/home/about- | us/directory/professor... | | Peroxide has at best generally been found to useless, and at | worst you're introducing active chemistry to your ventilation | system (including ozone). If you want to get rid of garbage | in your air then (a) exchange it at ASHRAE-recommended | volumes, and (b) use high-MERV/HEPA filters. | | In wildfire zones and in wildfire season you can perhaps add | charcoal filters--if your system is designed to handle the | pressure/head loss--to get rid of the smoke-y smells. | | There is no need to conduct chemistry experiments on | yourself. | anecdotal1 wrote: | You might actually want to do some research on these first. | These have been installed with great success at Chipotle | stores, meatpacking plants, hospitals, veterinary | hospitals, hotels, schools (Chicago Public Schools 138), | universities, Office Depot's corporate HQ, the IRS facility | in Austin TX to name a few... | lazide wrote: | How is that 'great success' measured and verified? | Empact wrote: | > All that's needed for good indoor air quality (IAQ) is an | ERV/HRV which exhausts stale indoor air and brings in fresh | outdoor air (through a filter) | | The recommendations you mention are together features of the | Passive House[1] building standard that seeks low energy use as | well. If you build a building to a high standard, it will have | a tighter envelope to retain heat/cool and protect against | water intrusion. If the envelope is tight, you must actively | manage airflow through an ERV/HRV. The consequence is that | these buildings are supplied with continuous fresh air, and | their ERV can be set up to dynamically react to air quality and | other issue to ramp up the transfer.[2] | | There's a subculture of builders pursuing these qualities in | their building, represented for example by groups like | "Building Science and Beer" in Austin[3], and Matt Risinger's | Build Show[4]. | | [1] https://www.treehugger.com/what-is-a-passive-house- | principle... | | [2] https://www.broan-nutone.com/en-us/ai-series | | [3] https://www.instagram.com/bs_and_beer_atx/ | | [4] https://www.youtube.com/@buildshow/videos | throw0101a wrote: | > _The recommendations you mention are together features of | the Passive House[1]_ | | ERV/HRV are actually part of regular building codes in many | areas. The province of Ontario: | | * https://www.greenbuildingadvisor.com/article/ontario- | imposes... | | * https://airfixture.com/blog/ontario-building-code- | ventilatio... | | * http://www.mah.gov.on.ca/AssetFactory.aspx?did=15947 | | * https://web.archive.org/web/20180626073728/http://www.mah.g | o... | adolph wrote: | 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. | mensetmanusman wrote: | 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. | throw0101a wrote: | > _It's possible to have a UV system that does what you | want without the downside, but it does cost._ | | The main downside is that you are introducing a chemistry | experiment into your ventilation system. | | If you want clean air, then (a) cycle in/outside air at | ASHRAE-recommended volumes, and (b) use high-MERV/HEPA | filters. | | In wildfire zones and in wildfire season you can perhaps | add charcoal filters--if your system is designed to handle | the pressure/head loss--to get rid of the smoke-y smells. | schiffern wrote: | What I really want is a system that has | | * Positive pressure maintenance, so that any air leak | paths are not introducing outside air pollutants | | * HEPA filtration, using two filters in series so I can | "cycle through" filters, moving the post-filter to the | pre-filter location and using a brand-new post-filter | (this is similar to the ISS water filter change | procedure, and maximizes expendable filter utilization); | by the series-parallel circuit math, this should requires | _four times_ the total area of HEPA filter | | * pressure drop sensors, so I only need to replace the | HEPA filter when necessary | | * activated carbon post-filter that lets me to replace | only the granules themselves, using bulk activated carbon | | * washable screen prefilter, to avoid premature | saturation of the HEPA medium with >10 micron particles | | * washable electrostatic prefilter, to avoid premature | saturation of the HEPA medium with <1.0 micron particles | | * HRV/ERV, to avoid unwanted heat and humidity transfer | to the outside air | | * HRS/ERV Bypass, so I can use "free cooling" / "free | heating" to exploit natural temperature differences over | the day | | * (optional) MERV-13 post-prefilter, to intercept ~95% of | PM2.5 and greatly extend the life of the HEPA filter | train | | Does anyone know of a system that has all these features? | adolph wrote: | 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. | steviedotboston wrote: | I don't think the clear water and clear air analogy works very | well. They seem to be very different cases. Keeping clean and | dirty water separate is trivial and requires no more advanced | technology than plumbing. Keeping clean and "dirty" air separate | is impossible. We will always breathe air that includes | pathogens. That isn't to say there should be efforts to improve | air quality, but I think a lot of times analogies like this | oversimplify things. It's easy to eradicate cholera through | cleanliness and modern plumbing, but we will never eradicate | airborne viruses through air filters and masks. | JBorrow wrote: | "Cleanliness and modern plumbing" include massive water | treatment facilities, digging up every street, laying billions | of miles of pipe. | steviedotboston wrote: | The main effort is separating drinking water and waste water. | Keeping them as far away as possible and preventing | contamination. There is no way to do that with air. The air | we breath in and the air we breath out will always mix. The | best we can hope for is some amount of dilution with fresh | air/filters, bit at the end of the you are never going to be | able to achieve the same thing with airborne viruses that we | did with waterborne illnesses. The flu, covid, etc are with | us for the long haul. | gridspy wrote: | It's a good analogy. Invest in infrastructure to extract dirty | air and deliver clean air into living spaces. Provide suitable | standards and technologies to do so. | | It would be cheaper than the infrastructure to extract dirty | water and deliver clean (treated) water because we don't need | to transport the air anywhere near as far and air treatment is | simpler. | EGreg wrote: | I designed this two years ago... | | https://uvspinner.com | | Tried to get NYC officials to get interested -- went through some | channels that my friends had. Nothing. | | Anyone here interested in doing it? | leblancfg wrote: | I wish the author had spent more time to unfold the public vs | private debate here: | | >if a country installed all the measures I mentioned | | As opposed to the wastewater infrastructure in the first section | that can be mandated and put in motion by a government, it's up | to individuals and institutions to install the measures. | | This makes implementation significantly more challenging, as it | relies on the collective efforts and cooperation of numerous | parties, each with their own priorities and resources. | Government-led initiatives, on the other hand, can be more easily | streamlined and enforced, ensuring a higher degree of compliance | and effectiveness. | gizmo686 wrote: | Governments are perfectly capable of setting building codes. | This isn't an instance fix, but would be effective over the | long term. | | Governments also have a well established mechanism to | incentives faster compliance: tax refunds to offset the cost of | improvement. We already offer such incentives for energy | efficiency improvements (some of which actively harm | ventilation). | | From an engineering perspective, the clean air proposals are | much easier than wastewater management. There is no centralized | infastructure needed. Every building can be upgraded | independently, and the people in that building will see an | immediate benefit. | | Further, the upgrades needed are typically not that major. Most | building already have a forced air HVAC solution. These | solutions already have inline air filters, and often already | have the ability to actively pull in fresh air. | | We can get significant improvement my simply leaving the fan on | these units running regardless of if they are actively | heating/cooling; and using already available high quality | filters. | | In that subject, a quick PSA to home owners: if you have not | changed your HVACs filter recently, you probably should. | photochemsyn wrote: | Clean air and water issues are not limited to biological | contamination with pathogenic microbes and viruses, and some of | the suggestions (ensuring good ventilation) run into problems | when external air quality is dangerously bad (when health | agencies tell people to keep their windows closed). | | It's not entirely unlike water issues, for example the Thames was | used to dispose of wastes from animal slaughtering, leather | tanning, production of dyes from coal tar, alcohol distillery | wastes as well as for human excrement. Cleaning up air quality | requires addressing these issues as well (coal power plants, | diesel truck emissions, agricultural dust, etc.). | markrankin wrote: | "The expectation of clean water in wealthy countries is enabled | by technology and infrastructure; like effective sewage systems | and water treatment facilities. But to a large extent it is also | enabled, and was initially bootstrapped, by sound policymaking | and regulation. | | Regulation requires verification." | | Regulation of water does not require verification. We live on a | planet where clean water is abundant and cannot escape the | planet's atmosphere. Why you think we need to measure how this is | verified is beyond the beyond's. | | Here's a wiki page reference if you need help measuring how much | water exists on Earth: | | While the majority of Earth's surface is covered by oceans, those | oceans make up just a small fraction of the mass of the planet. | The mass of Earth's oceans is estimated to be 1.37 x 1021 kg, | which is 0.023% of the total mass of Earth, 6.0 x 1024 kg. An | additional 5.0 x 1020 kg of water is estimated to exist in ice, | lakes, rivers, groundwater, and atmospheric water vapor.[20] | | https://en.m.wikipedia.org/wiki/Origin_of_water_on_Earth#Ear... | twojacobtwo wrote: | There are only so many ways and places to extract clean water | for large populations in an efficient way. Once water is used, | it has to go somewhere, which is back into the water system. | Every person/population downstream then no longer has 'clean | water' without verification. We could have 10x the clean water | we have now and we would still have to consider this aspect. | MontyCarloHall wrote: | 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. | GordonS wrote: | If that turned out to be the case, maybe we could have annual | "vaccines", which would exist only to trigger anti-viral | activity? | Symmetry wrote: | 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. | MontyCarloHall wrote: | 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. | mrob wrote: | If it turns out that actual pathogens are necessary, and we | can't use the kinds of harmless bacteria that get sold as | "probiotics", it would still be better to identify pathogens | with optimal risk:benefit ratio and determine the optimal dose. | Exposure to wild pathogens varies widely, so very few people | will be lucky enough to have the best exposure. | sdfjkl wrote: | The Thames is still very much opaque. Not near-opaque. | dgroshev wrote: | It's just silt churned up by high tides. When you're on the | river, you can easily see that bits shielded from the turbulent | flow, where the silt has a chance to settle down, are crystal | clear. You can also see eels, seals, cormorants, kingfishers, | seagulls of all kinds, and lots of life generally. It's great. | sergioisidoro wrote: | 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, I think the first step is really | to get visibility to the problem, especially to the costs of the | problem (productivity, public health, sick leaves, etc). | | [1] at the levels found in my apartment | clairity wrote: | > "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 intrinsic maladaption | to CO2, which is actually vital to life on earth. it's | fashionable to hate on carbon right now (it's mediopolitical), | and that's really all there is to it. | | particulates, VOCs and chemical off-gassing, on the other hand, | do have known mechanisms of harm, and that's something you | should be more concerned about, but not yet alarmed. most of | that pollution comes from cars and coal/gas power generation, | so long-term, we should move toward more efficient habitation | (e.g., denser cities, public transit) and cleaner power | generation (including nuclear) if we really care about our | collective health. | | practically no one should be worried about CO2 in their daily | lives. it's thoroughly a red herring. | fatuna wrote: | 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. | clairity wrote: | here's a USDA fact sheet summarizing the effects of CO2 at | different concentrations that's more easily digestible than | an academic paper: https://www.fsis.usda.gov/sites/default/ | files/media_file/202... | Rebelgecko wrote: | There are a number of studies that have found that CO2 | levels lower than the OSHA limit of 5,000 ppm can still | cause issues like slight cognitive impairment and worse | sleep (however there's also a few studies that have found | no or minimal impact of levels below 5,000ppm) | sergioisidoro wrote: | 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 cognitive function. For every | 500ppm increase, we saw response times 1.4-1.8% slower, and | 2.1-2.4% lower throughput" | | https://www.hsph.harvard.edu/healthybuildings/2021/09/09/imp. | .. | clairity wrote: | 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 10x 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. | sergioisidoro wrote: | See, they are debatable after all - we are debating them. | There is data, there are some correlations that are | statistically significant, and some raise even more | questions -- like why performance lowers at 1200ppm, but | goes back up at higher concentrations in this article | published on Nature in a very controlled environment - | https://www.nature.com/articles/s41526-019-0071-6 | | I don't think this topic distracts from anything. I live | in Finland, where indoor air quality is a big topic | (mycotoxins and spores due to mold in old houses, burning | wood in residential areas due to particulate emissions on | cold days, construction codes, etc), while the country is | making strides to become carbon neutral, and has one of | the lowest economical inequality in the world. | | But anyway, as I mentioned in the initial comment, the | high CO2 just raised my attention to the bad ventilation | of the house, and that includes ventilation of | particulates from activities like cooking. | rcme wrote: | I think the first step would be to buy a second monitor, | ideally from a different manufacturer, and verify that your | readings are actually correct. My experience is that cheap | monitors are basically random. | bsder wrote: | Precisely this. | | I haven't seen anybody take any of the cheap CO2 sensors and | demonstrate that they are anywhere in the range of the | readings of a lab grade CO2 sensor. | nicenewtemp84 wrote: | If your reader raises it's reading as you sit in a small | room, and lowers when you open a window... It's probably not | at risk of being random. Inaccurate maybe, but still sensing | in the correct direction. | lazide wrote: | At least one (Big Clive pulled it apart I think?) had an | Ethanol sensor in it. | sbaiddn wrote: | 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! | Abekkus wrote: | 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. | sbaiddn wrote: | Does this "filtered vent fan" exchange air with the | outside? If not, Im not interested. | symlinkk wrote: | Are you talking about a fan that simply blows outside air | in? Wouldn't that basically fight what the HVAC is doing? | AFAIK the only real solution is an ERV / HRV, and they are | extremely expensive (like $10k in my area) | balfirevic wrote: | No direct experience, but single-room HRV units look | pretty cheap | | https://www.amazon.co.uk/single-room-heat-recovery- | ventilati... | BizarroLand wrote: | 85-95% isn't suspiciously low. | | Where are you getting this information from? | isp wrote: | > So if we want to do something, I think the first step is | really to get visibility to the problem | | A sensible first step would be to very visibly display CO2 | monitors in buildings (e.g., throughout office buildings, | schools, etc) | | Once the CO2 levels become visible, this in itself creates an | incentive to improve. | | Related from UK (2021): "All schools to receive carbon dioxide | monitors" - https://www.gov.uk/government/news/all-schools-to- | receive-ca... | bsenftner wrote: | 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, but the client's office windows do not open, and | of course neither do the airplane windows. | | I've also noticed when working indoors or when driving, if | the CO2 is above 1500 I get drowsy, so the degree it is no | longer responsible driving a car. | | Air safety: are we going to fight a moronic battle over this | too? | dylan604 wrote: | >if the CO2 is above 1500 I get drowsy, so the degree it is | no longer responsible driving a car. | | so the old adage of rolling down the window when driving | might actually have some factual logic to it. of course, | people are only considering that when at the extreme end of | trying to stay awake from already driving past safe limits, | but it could easily make a long haul trip more bearable by | remembering to crack the window at intervals. then again, | if you're riding with my buddies, you were already having | to crack the windows at intervals, but for _other_ reasons. | btbuildem wrote: | Seems like yes, we are. A good proportion of people abhor | change, even if it would make their lives better. | blkhawk wrote: | 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 the "eCO2" type - in that case | well I doubt you get anything out of that thing in a plane | except a high number. | | One thing I noticed is that CO2 seems to "flow and pool" in | certain places as it seemingly "rains" down and the room is | "filled" from the bottom up. A Table for instance might | develop a layer that is thick enough for my meter to hoover | it up (it has a fan). | Retric wrote: | 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. | johnmaguire wrote: | > 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. | weaksauce wrote: | the oxygen levels in airplanes are not high because they | only pressurize the cabin to be about a 7000' | pressurization. that's roughly equivalent to a lot of | mountain town altitudes... think flagstaff. | tesseract wrote: | Well, there's less of it, since typical airliner cabin | pressure is equivalent to being at 8000ft altitude or so. | Do you typically spend long durations driving in the | mountains? | hammock wrote: | When driving, does running the air (not on recirc) not | exchange enough air? | bsenftner wrote: | 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. | schiffern wrote: | 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" when I'm away from a major city or high- | traffic road (and _not_ when driving behind a soot- | spewing diesel bus /semi/garbage/cement truck). | | I wish there were some way to automate this logic! | | --- | | (and yes, my dear observant reader, if I could | recirculate "only" 90% of the exterior air it would | achieve the same steady-state result, but modern cars got | rid of the "slider" that lets you select a _percentage_ | of recirculate air... _::sigh::_ ) | sizzle wrote: | 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? | bruckie wrote: | There should be very low levels of CO (at least from your | car) in the engine bay, since exhaust is vented out the | back of the car, and your engine shouldn't be leaking | exhaust gases in other places. You might have some CO | there from the cars in front of you, though. | Retric wrote: | 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. | schiffern wrote: | 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. | giraffe_lady wrote: | 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. | marcosdumay wrote: | 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 science?" line. | | Crazy years, dominated by completely random propaganda. | Discussions on calmer times follow different rules, and | if nobody decides to spend a lot of money stopping it, it | can follow rational, evidence based lines. | giraffe_lady wrote: | 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. | robocat wrote: | 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). | anonymouskimmer wrote: | > 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... | XorNot wrote: | Before I stopped being in offices I was looking for a | portable CO2 monitor to take into meetings to see how quickly | we ended up at 1000+ppm. The tendency to overcrowd meeting | rooms I was convinced was basically a driver in devaluing | them - the CO2 is going up and up and up and people's | cognition is slowly ebbing alongside regular old fatigue. | morkalork wrote: | I always blamed it on heat accumulation, after stuffing all | those bodies, laptops and even old inefficient | lighting/projectors into a confined space it gets way too | warm, then the body slows down to compensate. | beebeepka wrote: | If possible, I recommend ventilation by creating a current by | opening the front door and cycling every room (windos, balcony | doors) of your apartment. | | I do this every day regardless of the season. Works best during | windy weather | InCityDreams wrote: | *watch out for slamming doors and windows :-) Took me ages to | work out how best to perform such in my place, and yes - | daily opening, even for 5 minutes - does seem to help (me). I | also do it last thing at night. In the morning - a less | stuffy apartment. On work days, I'll probably open for a few | minutes before going to work, but definitely after getting | home. | oblak wrote: | I use mostly chairs and pillows to prevent doors from | slamming. What challenges did you meet at your place? | kccqzy wrote: | * * * | aidenn0 wrote: | I do wonder how much of it is CO2 levels themselves and how | much of it is high CO2 being a proxy for poor ventilation. | mypastself wrote: | Not to hijack your thread, but I wonder if anyone here's built | their own Raspberry/Arduino CO2 monitor? Which (reliable) | sensors did you use? Did you find it more affordable than | purchasing a monitor, especially if you already had unused | microcontrollers lying around the house? | Lukas_Skywalker wrote: | I built one based on the AirGradient DIY sensor [1]. It is | open source, and you can order PCBs or build them yourself. | It is also compatible with ESPHome. | | It uses the "Senseair S8" CO2 sensor, which costs a bit | (25-30$), but (according to AirGradient) has a very high | quality. | | [1]: https://www.airgradient.com/open- | airgradient/instructions/di... | Rebelgecko wrote: | Seconding this recommendation. I was surprised how easy and | cheap it was to order my own tweaked PCBs. Airgradient has | also done a lot of testing to determine which components | work well and what their different failure modes are. | | Depending on how many you build at a time, you can source | all the parts for maybe $40-$60. Assembly is | straightforward as long as you're comfortable with through- | hole soldering (and if not, this is a great chance to | learn). The design is also modular enough that it's easy to | skip on things like the thermometer or particulate matter | sensor if you're so inclined. | GloriousKoji wrote: | The microcontroller is the cheapest part! The good sensors | that you want to use are in the $45 range. Look for "True" | CO2 sensor that use some sort of optical technique to measure | CO2. A lot of the really cheap CO2 monitors just measure VOC | with some kind of metal element and approximate CO2. I like | Sensirion SCD30 or SCD40. | ProZsolt wrote: | I'm currently developing my own monitor based on Sensirion | SCD40(CO2/temperature/humidity) and Plantower PMS7003(PM2.5). | The SCD40 is lot smaller than any NDIR sensor, but with the | same accuracy[1]. | | My goal is to get a cheap (~$50) sensor in a small package | that I can put in every room in my house. It will be modular | so I skip the display and the PM2.5 sensor and it can be | cheap as ~$25 | | [1]: https://www.airgradient.com/open- | airgradient/blog/co2-sensor... | [deleted] | Cthulhu_ wrote: | 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. | BizarroLand wrote: | 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. | c3534l wrote: | > , it shocked me and raised awareness to how poor my indoor | ventilation is. | | Do you _want_ indoor circulation? Wouldn 't that just mean your | apartment loses heat/AC? | GuB-42 wrote: | Yes, ventilation causes heat losses, but it is necessary. | | There are ways around it though. The simplest is to not make | sure ventilation goes where it needs to go. Modern buildings | use mechanical ventilation to make sure every living space | gets properly ventilated so one room doesn't get too much and | another too little. Even better, some building use heat | exchangers to heat/cool the incoming air with outgoing air, | minimizing losses. Other techniques involve passing the fresh | air underground, which, in a temperate climate gets you some | free heating in the winter and free cooling in the summer. | | Obviously, to limit heat losses, you want to reduce | conduction and radiation too, which can be done without | sacrificing ventilation. | Cthulhu_ wrote: | The issue with heat exchangers and the like is noise on the | one hand (can be suppressed of course), having it on the | right setting (not too high if there's few people, not too | low if there's many), and keeping the conduits clean (dust, | moisture and heat is a great combo for some). | graeme wrote: | Sure, but it's not nearly as costly as you'd think. We pay | for all kinds of things. Including, compared to the past, | much warmer air in the winter and much cooler air in the | summer. | | Growing up we used to put on sweaters, wear shorts, use fans, | have the windows open in a car. | | Changing our heating/cooling preferences to get rid of all | that costs money. People don't mind. | | But somehow, spending a small bit to _breathe well_ and avoid | indoor pollution /viruses is beyond the pale. | swiftcoder wrote: | In a heating/cooling system that has been specifically | designed to improve ventilation, one can pull fun tricks like | using the outgoing (stale) air to help heat/cool the incoming | (fresh) air. Also in some places houses are built with enough | thermal mass that the air within the building doesn't contain | the majority of the heat therein. | | In general there is likely some level of ventillation that | will be worth taking on slightly increased heating/cooling | costs. | kevincox wrote: | You can use a heat exchanger to get "fresher" air while | keeping the heat/cool inside. Although many places don't have | this in place. It is probably mostly due to lack of awareness | or concern than any technical reason. | endisneigh wrote: | Cost | switchbak wrote: | Letting your warm air go directly outside also has a | cost. | | Getting poor air quality for decades also has a cost. | | Typing more than a one word reply is pretty cheap though. | endisneigh wrote: | you're right. things have tradeoffs. the point is that | most barely have central AC with vents, let alone an HRV. | switchbak wrote: | Most homes don't have HRVs not only due to cost, but | because homes didn't used to be tight enough to require | them. We also didn't understand how important fresh air | is. | | Many homes didn't have AC because a) it was expensive, | and b) you used to not need it as much. | | And plenty of people can afford these things, cost is not | the only consideration nor some magic word to dismiss the | tech generally. | endisneigh wrote: | No one is dismissing anything | LeonM wrote: | 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 at night. So I improved the ventilation in my | bedroom, and in my case it helped me to achieve better sleep. | ct0 wrote: | 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. | kccqzy wrote: | 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.) | prmoustache wrote: | you want to sleep below a tarp then, not in a tent. | Cthulhu_ wrote: | It'll depend on the tent, I don't immediately associate | tents with good ventilation. | gumby wrote: | A tent with poor ventilation rapidly becomes soggy. | anonyfox wrote: | ... and people make joke about us Germans need to do | ,,stossluften" (opening all windows in parallel to get fresh | air in fast). | | also, are there really people that can (or even prefer!) to | sleep with closed windows?! Only with AC blasting, right? | balfirevic wrote: | Yes, that's the only way to have nice cozy temperature | throughout the year. Heating will be on during large part | of the year, but during the summer AC will be on. Just | working gently, though, no blasting. | | I'd love to have ventilation with heat exchanger, but | that's basically unheard of where I live. | switchbak wrote: | Some new buildings use an HRV system which circulates fresh | air in while recovering some of the heat of the exhaust | air. | cultureswitch wrote: | I can't sleep with either AC, simple ventilation or windows | open. Too much noise. In rural environments too, just a | single cricket is capable of keeping me awake. | | Sometimes in very hot weather I do leave the windows open | at night but it's due to heat, not air quality. | heipei wrote: | Try sleeping with earplugs. I started doing it out of | necessity, and it was awkward at first, but once I got | used to it was really life-changing. Sleeping with plugs | in feels like being embraced by silence and darkness, so | much so that you can sleep the whole night through and | feel more refreshed in the morning. | aidenn0 wrote: | Aside from urban noise, I don't sleep well if an open | window is too close to my bed because I end up with | congested sinuses. | GloriousKoji wrote: | It's way too loud if I sleep with the windows open. | za3faran wrote: | Which monitor manufacturer are you using? | sergioisidoro wrote: | I bought mine from a construction material supply web store, | and was looking for one of the cheaper ones. Its a Trotec. I | wouldn't trust the absolute values so much, but i believe | it's directionally correct. | panchtatvam wrote: | [flagged] | danans wrote: | > An aside: ventilation plus filtration is the major reason that | the risk of Covid infections on flights was and is so relatively | low: air in the cabin is replaced every couple minutes, fresh air | is drawn from outside the plane, and mixed with recycled air | passed through HEPA filters. | | IME, the most effective thing to do in a house is filtration | inline with the intake of a ventilation system. | | In my case, I have an activated carbon and a MERV13 filter that | cleans incoming outdoor air just before it's fed to the heat | recovery and distribution system. | | You still need a separate recirculating filtration system to deal | with particulates generated within a house. ___________________________________________________________________ (page generated 2023-05-01 23:01 UTC)