[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)