[HN Gopher] Disinfection with Far-UV (222 nm Ultraviolet light) ...
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Disinfection with Far-UV (222 nm Ultraviolet light) (2020) [pdf]
Author : deegles
Score : 55 points
Date : 2023-02-14 19:02 UTC (3 hours ago)
(HTM) web link (www.boeing.com)
(TXT) w3m dump (www.boeing.com)
| donsupreme wrote:
| I am curious if the ambience air can be too "sterile", that we
| will come to find out there are some good microbes in the air
| that is beneficial to our health.
| qbasic_forever wrote:
| Our body would have evolved to keep whatever these 'good'
| microbes are in and near our lungs, much like it does for our
| intestines and digestive system. The lack of this system, and
| the evolution of things like hair and mucous in our nose to
| filter and trap foreign objects is a pretty good hint that our
| body doesn't want anything except our clean atmosphere in our
| lungs.
| malfist wrote:
| Fair, but your body also does away with things it's not
| using. An inactive immune system for too sterile environments
| may result in not being able to protect yourself in less
| sterile environments, or the immune system finding uses for
| itself, i.e. an autoimmune disease like allergies.
| qbasic_forever wrote:
| The immune system is not a muscle--you don't need to keep
| exposing yourself to pathogens. Think how ridiculous that
| sounds--are you going to go get rabies, ebola, HIV, brain
| eating bacteria, etc. to be 'healthy'?
| AuryGlenz wrote:
| Well, keep in mind humans didn't evolve to live in big cities
| and children in daycare and schools. I would think that the
| past 500 years or so the amount of illness each person suffers
| has gone up exponentially.
|
| Viruses are also linked to all sorts of nasty outcomes like
| Alzheimer's, cancer, etc. I doubt we'll have any means to knock
| transmission back a ton anytime soon but it'd be nice to do
| what we can.
| purpleblue wrote:
| At the beginning of the pandemic, I read about UVC light and
| purchased a UVC light bulb before they ran out online. I used it
| to sterilize my N95 masks which were impossible to find, and all
| the research I did showed that you could do this 20+ times
| without affecting air flow or filtration of the mask. I even
| found studies that talked about how to use it to disinfect flu
| virus so I used those as a guideline as to how long I should
| expose the masks. I even went so far as to buy ajar and tested
| that the UVC light at least killed bacteria as advertised. I know
| viruses are much tinier and there's no way to test for the virus
| but at least I knew it was working as advertised for bacteria.
|
| Of course all this ended up being useless, but it was a fun
| project during the pandemic.
| smileysteve wrote:
| similar, i read something about uv-c in 2019; and also how
| washing machines most active cleaning is from water (they don't
| kill things well), so had added a uv-c light to "treat" my
| laundry.
| jefftk wrote:
| Dereck Lowe ("In the Pipeline") has a good article on germicidal
| 222-nm: https://www.science.org/content/blog-post/two-twenty-two
| jbm wrote:
| The Canadian government has a page that includes some information
| about the effects of Far-UV light against Covid-19.
|
| https://www.canada.ca/en/public-health/services/diseases/201...
|
| > A whole room UV simulation demonstrated a far UV-C lamp
| (207-222 nm) could further reduce SARS-CoV-2 by 50-85% compared
| to ventilation alone and with both far UV-C and high ventilation
| the SARS-CoV-2 viral count was reduced by 90% in 6 minutes and
| 99% in 11.5 minutes Footnote 5.
|
| I wonder if this is something that I could add to my pre-existing
| home ventilation system; no concerns at all about skin exposure
| (which doesn't seem to be an actual issue based on this Boeing
| paper), and it shouldn't be so hard.
|
| * I found this (https://faruv.com/) but I don't know how reliable
| they are.
|
| That said, if this really was that effective, I don't understand
| how viruses and bacteria are able to survive outside with our
| fusion-powered UV ray generator in the sky.
|
| -edit- * I feel dumb, here it is at the end of the summary. Looks
| like Boeing is working w/ faruv.
|
| > Boeing recently entered into patent and technology licenses
| with Healthe(r) Inc. and FarUV Technologies. Under these
| licenses, both companies will produce and distribute a commercial
| Far-UV 222 nm mobile wand, helping airlines and potentially
| others reduce the impact of the coronavirus pandemic.
| hedgehog wrote:
| There are a few different ways I've read about far UV being
| deployed, one of the interesting ones is illuminating the upper
| few feet of a room. Exhaled breath tends to rise so apparently
| doing just the top of the room is more effective than you might
| expect. I hope this pans out to be effective, it would be a way
| to improve air quality without adding more noise to the space.
|
| Edit: The article's claim is that because far UV is absorbed in
| the upper atmosphere there's not really any evolutionary
| pressure for organisms to develop protection. Larger organisms
| just happen to be protected by virtue of our size.
| purpleblue wrote:
| The wand will be useless unless they hold it above the area for
| 30+ seconds, which probably won't happen. Or unless the light
| is extremely intense which sounds dangerous.
| samstave wrote:
| Wouldnt it be best to create a modular off-the-shelf
| instalable, positive pressure man-trap (extendable to walkable
| tunnel length, in the entrances to large public areas
| (stadiums, airports, trains, malls, etc)
|
| turn that wand into wall panels and let people walk through it
| - just like any other clean-room-style man-trap?
|
| https://i.imgur.com/8dMGNjN.gif
| ericbarrett wrote:
| UV-C is absorbed by the ozone layer.
| com2kid wrote:
| > That said, if this really was that effective, I don't
| understand how viruses and bacteria are able to survive outside
| with our fusion-powered UV ray generator in the sky.
|
| There is a reason that even during the height of the pandemic,
| that outdoor events were not a large source of transmission.
|
| People going into bars or houses after
| marching/protesting/partying were a problem, but standing
| around in the sunshine, even in a reasonably dense crowd,
| wasn't ever really a problem. (AFAIK, I remember news articles
| going "well that didn't turn out as bad as we all thought it
| would")
| modestmc wrote:
| Nice to see this on HN, this is a big deal. I did research in
| 2021 to generate Far-UVC using nonlinear plasmonics.
|
| The holy grail for this technology is a Far-UVC Diode. The guy
| who won the Nobel Prize for the blue LED (IIRC) is working with
| other physicists at UCSB to try and create said diode:
| https://www.news.ucsb.edu/2020/019949/uv-lights-way
|
| If you want to learn more about Far-UVC itself (safety, etc),
| David Brenner is the real MVP: http://www.columbia.edu/~djb3/
| Maursault wrote:
| > recently published studies have demonstrated that UV light at
| 222nm has the same germicidal capabilities of 254nm light without
| damaging skin or eyes.
|
| 222nm may have the same _capabilities,_ but not the same efficacy
| and efficiency as 254nm (or 185nm, the germicidal action if which
| is it creates ozone, which does the disinefecting). Still, if it
| works but just takes longer without the sunburn and blindness,
| whether by proximity to 254nm such that some 254nm is still
| present, and /or by proximity to 185nm such that ozone is still
| created, well, ok.
| hedgehog wrote:
| According to the linked article: "While the effects on live
| tissue are diminished, Far-UV (222 nm light being the most
| prevalent) has increased efficacy for killing bacteria and
| viruses."
| Maursault wrote:
| That's misleading, increased efficacy as opposed to what? A
| control? It's not more than 254nm, which has been long
| proven, in repeated studies, to be the most efficient
| germicidal wavelength, decreasing in near wavelengths
| depending on how close they are to 254nm. 222nm is only 32nm
| of wavelength difference to 254nm, and I'll wager that even
| 238nm is more efficient than 222nm, but maybe 238nm burns
| skin. 222nm is nearly half way between 185nm and 254nm, so it
| will have some of the germicidal effects of both wavelengths,
| but it won't be more than either 185nm or 254nm. But it may
| be enough, and if it doesn't hurt people, then kudoes.
| scythe wrote:
| >254 nm
|
| ... which just happens to be _exactly_ the second spectral
| line of a low-pressure mercury-vapor lamp. Actually 253.7.
| The other line is 184.5. Are you sure that the study you
| read isn 't just reporting this wavelength as ideal because
| we have a convenient source of it? Efficient far-UV sources
| tend to be few and far between. It would be an awfully big
| coincidence if the two major spectral lines of an Hg plasma
| just happen to be the two ideal wavelengths for
| disinfection.
|
| FWIW, zinc vapor has a persistent line at 214 nm, but I've
| never heard of this being applied in a commercial bulb.
| Other relevant possibilities are all toxic.
| viraptor wrote:
| Just read the article. It's "compared with 254 nm light".
| Both sentences are in the abstract.
| maximilianburke wrote:
| One of the most driven* and intelligent people I have ever had
| the opportunity to work with (Saimir Sulaj) left my company to
| found a startup that's building far UV disinfection devices:
|
| https://www.uvxinc.com/
|
| *I mean, it requires a certain kind of stubborn determination to
| do a hardware startup, and I hope he's crushing it.
| com2kid wrote:
| Unfortunate it is one of those "inquire now" things, if there
| was a "buy now" link I'd pick a few up right away.
| londons_explore wrote:
| We need more studies, or maybe metastudies, that compare the
| germicidal benefits of UV lamps with the health disadvantages
| (skin cancer, ozone).
|
| It seems that there is consensus on both effects, but I can't
| find anything conclusive that allows the scale of the effects to
| be measured sufficiently to do a benefit/cost analysis for each
| type of light spectrum and usecase.
| [deleted]
| modestmc wrote:
| Far-UVC (~205-222 nm) light can't penetrate cell walls and thus
| does not risk DNA damage.
|
| However, our skin heavily depends on friendly bacteria to do
| useful things. One concern that I have yet to see research
| testing is the impact of extended Far-UVC exposure on these
| microbial populations.
| lazide wrote:
| Skin cancer is easy to prevent by not allowing the light to
| shine directly on anyones skin, and using non-UV reflective
| enclosures.
|
| Ozone is already a known and easily tested quantity, and
| generally only happens at 240nm and lower wavelengths. So 222
| as listed might produce some, but doesn't seem optimal (180nm
| seems better).
|
| Found a paper - seems likely that is the case
| [https://onlinelibrary.wiley.com/doi/full/10.1111/php.13391]
|
| Note scale on the first graph.
|
| edit: ah hah, but many of these lamps have defects that can
| result in higher freq. light emission and high ozone
| production! See later parts of the paper.
| blairanderson wrote:
| I recently visited a national trade show for HVACR folks and
| found this company:
|
| https://www.amazon.com/Blue-Tube-UV-Light/dp/B00D48XDO0/
|
| Thought it might be applicable to computers, but realized that UV
| breaks-down PLASTICS as well, which is why you mostly find in
| ducting.
|
| Very cool stuff if you're into clean/sterile living.
|
| Note: Most of the dust in your home is comprised of human skin.
| Unless you've had an industrial vacuuming, other people's skin is
| moving around your house or gumming up the walls of your ducts.
| UV lights (and chemicals) are the only way to break that shit
| down.
| thedougd wrote:
| I believe these are for keeping your evaporator coils clean and
| funk free rather than cleaning your air. The air movies past it
| much too quickly.
| wnevets wrote:
| Wouldn't UV-light in ducting generate ozone? Even relatively
| small amounts of ozone can be harmful.
|
| > When inhaled, ozone can damage the lungs. Relatively low
| amounts can cause chest pain, coughing, shortness of breath and
| throat irritation. [0]
|
| [0] https://www.epa.gov/indoor-air-quality-iaq/ozone-
| generators-...
| Eisenstein wrote:
| Ozone is produced at 185nm. Standard germicidal UV-C lights
| are ~250nm. The issue is that some germicidal bulbs do not
| filter out the lower wavelengths and thus produce ozone
| (sometimes on purpose since ozone is also germicidal). See
| [0].
|
| [0] https://en.wikipedia.org/wiki/Ultraviolet_germicidal_irra
| dia...
| jefftk wrote:
| _> Standard germicidal UV-C lights are ~250nm._
|
| The article is about KrCl 222-nm lights, which people want
| because they're safe [1] to shine on people, unlike Hg
| 254-nm lights.
|
| [1] Probably -- I'd like to seem some specific additional
| experiments before widespread deployment.
| lazide wrote:
| 222nm is not safe to shine on anyone! It will definitely
| cause skin cancer.
|
| 254nm is also not safe.
|
| 254nm destroys ozone, interestingly.
|
| 240nm and smaller (160nm being the highest producing
| freq.) produce ozone.
|
| [https://onlinelibrary.wiley.com/doi/full/10.1111/php.133
| 91]
| bsder wrote:
| > 222nm is not safe to shine on anyone! It will
| definitely cause skin cancer.
|
| The whole point of using 222nm is that it doesn't cause
| effects on either the eyes or the skin. Consequently, you
| can use it at higher concentrations without worrying
| about the leakage.
|
| The issue, as I understand it, is simply that we don't
| have a decent LED monochomatic source. All of the
| currently available sources have broad spectrums that
| have to be filtered out.
| jefftk wrote:
| I don't see anything in your link about 222nm causing
| skin cancer? It's short enough that it shouldn't be
| getting through the outermost layer of skin, which is
| dead.
| lazide wrote:
| Welders have plenty of experience to contradict it. UV-C
| is usually blocked by the atmosphere, and most people
| don't get exposed to it directly - so it rarely comes up.
| But if you're sitting next to a UV-C generator, don't.
|
| It cleaves DNA the same as UV-B, and there is no reason
| to think it isn't cancer causing. There are a number of
| areas that can get exposed that have very thin epidermis,
| or none at all (eyes), though eyes would get retinal
| keratosis not cancer.
|
| That said, hopefully no one is spending enough time close
| to a high enough power UV-C source for this to REALLY be
| a problem.
|
| Welding Cite -
| [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5640727/]
|
| Notably, while having a higher skin cancer risk despite
| being inside a lot (shop welders, not shipyard welders),
| the vast majority of welders in that sampled population
| will have been wearing heavy protective clothing
| continuously. There was a noticeable increase in risk of
| skin cancer on the neck, which is one of the few areas
| that is not always adequately covered.
|
| Anecdotally, I knew folks who didn't wear proper full
| coverage PPE when welding and welded a lot (auto body
| repair in one case, farm equipment repair in another),
| and both died in their early 40's from multiple malignant
| melanomas. One of them, it was 10+ all at once, and he
| died in less than a year. No one was surprised,
| unfortunately. They were ALWAYS sunburned from it, and
| they didn't spend a huge amount of time outside
| otherwise. That is a pretty broad spectrum source though.
|
| UV-C As Potentially Mutagenic/Causing Damage not caught
| by normal replication suppression mechanisms -
| [https://pubmed.ncbi.nlm.nih.gov/9951833/]
|
| UV-C will also have no problem converting all sorts of
| organic chemicals into interesting, and often more toxic
| versions (albeit killing any organisms relying on their
| original structure in the process), same as UV-B or UV-A.
| the8472 wrote:
| welding light is broad-spectrum, so it's not relevant
| when comparing to a narrow-peak light source.
|
| > UV-C As Potentially Mutagenic/Causing Damage not caught
| by normal replication suppression mechanisms -
| [https://pubmed.ncbi.nlm.nih.gov/9951833/]
|
| _p53- /- human keratinocyte cell line_ means that those
| were in vitro experiments which don't account for the
| wavelength-dependent penetration depth, which is the
| point of discussion here.
| amluto wrote:
| And yet Far-UVC seems quite safe for people.
|
| Presumably what's going on is that longer wavelength UVC
| from welding is extremely dangerous.
| wnevets wrote:
| >Ozone is produced at 185nm
|
| Where did you find that 185nm number? Everything I see on
| google says ~250nm, not to mention the original post is
| about 222nm UV.
| lazide wrote:
| ~ 250nm actually destroys ozone.
|
| Smaller than 240nm creates it, to various degrees, with
| the ideal frequency being 160nm. 185nm is 'produces a
| noticeable amount'.
|
| [https://onlinelibrary.wiley.com/doi/full/10.1111/php.133
| 91]
| wnevets wrote:
| So the 254nm referenced by the linked product could
| actually reduce the amount ozone in the air? Assuming of
| course it wasn't also emitting lower frequencies.
| lazide wrote:
| Yes, but.... if you look at the paper, most of these
| lamps have some degree of lower wavelength light
| production. Some of them mitigate it through the glass
| they use, some of them make it worse. There is no good or
| easy way to tell. :(
| RetpolineDrama wrote:
| Carrier at least claims their UV upgrade does not produce
| ozone. Not sure how accurate that is though.
| throw0101c wrote:
| > _Very cool stuff if you 're into clean/sterile living._
|
| One concern I've heard about UV (and ionization) stuff is that
| you're adding 'active chemistry' into your ventilation system,
| which could possibly cause strange reactions you may not want.
|
| Besides 'bugs' and dead skin, there are are VOCs and other
| chemicals that we use in our homes: how will those reaction? If
| these units are new and working properly, things may be fine,
| but how many homeowners will do (or have someone do) regular
| inspections/maintenance? Having this stuff in non-residential
| places may be fine because Facilities has a role in keeping
| HVAC working: regular people don't do that.
|
| Having good filters (MERV >=13) will get rid of most of stuff
| you don't want in a simpler fashion.
| bilsbie wrote:
| Remember when we needed germs to exercise our immune systems?
| Remember immune systems?
| deegles wrote:
| let me know how your exercise with avian flu, yellow fever,
| HIV, ebola, hepatitis, etc etc etc goes.
| guntherhermann wrote:
| 1) Cool it with the snark
|
| 2) Ebola, Yellow Fever, HIV & Hepatitis aren't airborne, so
| probably wouldn't be the kind of viruses that the parent is
| talking about
| deegles wrote:
| They'll just have to chime in and clarify which pathogens
| they meant.
|
| I was snarky because the idea of "exercising the immune
| system" is misinformation and used by "immunity debt"
| proponents.
| marcosdumay wrote:
| Or maybe the 20th century increase in allergies was caused by
| the sheer amount of bad stuff we created, or maybe it's because
| of the sheer concentration of badly ventilated environments
| where hundreds of people pass through every day.
|
| AFAIK, there is no good evidence about any of those hypothesis,
| and weak ones for them all.
| 2muchcoffeeman wrote:
| I think there is a big difference between exercising your
| immune system and creating a Petri dish for air borne diseases.
| If COVID has taught us anything, it's that ventilation in many
| buildings sucks big time. We need to either improve
| ventilation, or start killing viruses.
|
| I mean, if you're going to go the naturalistic angle, then
| what's natural about squashing people into buildings with poor
| air flow?
| joezydeco wrote:
| UV will break down a lot of plastics, especially if stabilizers
| are not added. I'm curious why the study didn't mention this at
| all. How long can that bathroom hold out?
| jefftk wrote:
| If you're Boeing considering building it into planes it seems
| like you're in a great position for choosing UV-compatible
| materials.
|
| (Compared to the more normal situation of someone retrofitting
| an office, bar, or other normal space with 222-nm lighting.)
| EGreg wrote:
| Hi everyone. I had this idea two years ago, and made an entire
| website and video about it: https://uvspinner.com/
|
| Tried to get the NYC mayor's office interested, but they just
| pawned me off to a black hole of submitting forms that no one
| reads.
|
| If anyone still wants to do it, shoot me an email, username is
| greg with the domain "qbix.com" or add me on Facebook
| RenThraysk wrote:
| It's a shame we haven't figured out to make efficient Far-UV
| leds. The performance drops off a cliff once start to get below
| 265nm (IIRC)
| apienx wrote:
| This group's notorious for shining UV at fashionable pathogens.
| https://www.nature.com/articles/s41598-020-67211-2
| [deleted]
| lstodd wrote:
| Disinfection is harmful unless absolutely needed.
|
| Same as overuse of antibiotics - it only breeds more resistant
| strains and harms the immune systems because of lack of less
| resistant strains.
| blacksmith_tb wrote:
| Potentially - though it's a lot harder to evolve resistance to
| physical destruction than it is to a given antibiotic. The
| other aspect, aka 'the hygiene hypothesis' still holds, killing
| more pathogens may well lead to weakened immune response from
| lack of exposure.
| deegles wrote:
| The immune system is not a muscle that needs to be
| "exercised."
| msandford wrote:
| Germs don't get a chance to evolve resistance to this, at least
| as far as I can tell. At least not any more than humans have
| the opportunity to evolve a bullet defense.
|
| The UVC doesn't disrupt their metabolism or mutate their
| genetics subtly, it shreds their chemical bonds.
|
| It's much more like worrying that germs will evolve resistance
| to hydrogen peroxide or ethanol or iodine disinfectants. It's
| not impossible of course, but it'll require the kinds of
| mutations that make them entirely other organisms.
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(page generated 2023-02-14 23:00 UTC)