Disinfection with Far-UV (222 nm Ultraviolet light) (2020) [pdf]

https://www.boeing.com/confident-travel/downloads/CAP-3_Disinfection_with_Far-UV.pdf

by deegles • 3 years ago

133 141 3 years ago

jbm• 3 years ago

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® 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.

ericbarrett• 3 years ago

UV-C is absorbed by the ozone layer.

hedgehog2• 3 years ago

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.

purpleblue2• 3 years ago

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.

lightedman4• 3 years ago

I tested this at work. 222nm, 265nm, 275nm, 290nm. Petri dishes colonized with human underarm flora were prepared, closed, then incubated for an hour at 80F. tested times were 30 seconds, 60 seconds, 2 minutes, 3 minutes, 5 minutes.

222nm doesn't take even 30 seconds to wipe things out. Every dish was totally clean.

265nm needed about 2 minutes to sterilize.

275nm almost got the job done at 3 minutes and had the 5 minute dish totally clean.

290nm was frankly pathetic. All of the dishes survived with barely-decreasing colony count across increasing times. I estimate it'd take an hour of exposure to clean the dish.

com2kid2• 3 years ago

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")

Krssst• 3 years ago

If this was the reason, wouldn't it mean that we should be careful outside during the night?

samstave• 3 years ago

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

Maursault3• 3 years ago

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.

hedgehog2• 3 years ago

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."

Maursault3• 3 years ago

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.

blairanderson• 3 years ago

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.

wnevets4• 3 years ago

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-...

RetpolineDrama• 3 years ago

Carrier at least claims their UV upgrade does not produce ozone. Not sure how accurate that is though.

Eisenstein5• 3 years ago

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_irradia...

throw0101c• 3 years ago

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.

schiffern3• 3 years ago

HEPA gets all the hype, but if you can afford to recirculate the air for multiple passes (ie regular filtering, not a surgical theatre) then MERV-13 is the GOAT. It strikes a near perfect balance between particle interception efficiency and airflow volume.

Paradoxically, a 'more efficient' filter will generally achieves lower real-world performance (CADR) because the airflow drops so much.

The MERV rating are often hidden, instead you may need to look for numbers from a company-specific rating system like 3M's 'MPR 1900' or Home Depot's (yes, really) 'FPR 10.'[0]

(I almost don't want to include this last paragraph of info, because by sounding like an ad it will automatically 'taint' everything else, but fuck it....)

I find myself generally buying the 3M version (which is ~30% more expensive locally) which I observe has a much higher pleat count. That means more surface area (lifetime) and better pressure drop (airflow). By my math I come out ahead in cost per area of medium, which for me is a better metric than cost per filter.

[0] https://airfiltersdelivered.com/blogs/helpful-tips/merv-mpr-...

thedougd• 3 years ago

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.

eutectic3• 3 years ago

It's a myth that household dust is mostly skin cells. It only makes up a small percentage.

KennyBlanken• 3 years ago

You'll note the installation location - in the evaporator unit. It's to reduce mold growth in the evaporator unit, not sterilize air.

UV units intended for installation in return or supply ducts are snake oil. A waste of electricity and money (the bulbs have a pretty finite lifespan.) The velocity of air in most ducts is such that anything flying by wouldn't be sterilized, and you can just install a large air filter (like the Aprilair 413 others have mentioned) and it'll bring a lot more benefits to the table, namely much better reduction of dust.

The greatest problem with indoor air quality is offgassing of VOCs and other pollutants from construction materials, furniture, electronics, etc.

If you want the best indoor air quality: install a large filter like the Aprilair or some equivalent, an air exchange device, and if you have a gas stove/oven, switch that to electric.

lightedman4• 3 years ago

"UV units intended for installation in return or supply ducts are snake oil. A waste of electricity and money (the bulbs have a pretty finite lifespan.) The velocity of air in most ducts is such that anything flying by wouldn't be sterilized,"

If you just do the simple thing and point the lights in a self-facing ring in the duct, no, they will not work. The trick is to beam the light down the incoming pathway to drastically-increase the exposure time. Clean reflective surfaces in the ducting to even out the photon flux density will greatly help with this.

EGreg• 3 years ago

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

purpleblue2• 3 years ago

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• 3 years ago

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.

mr_toad2• 3 years ago

The water and soap remove dirt and grease that bacteria feeds on and lives in. You don’t need to sterilise your clothes, you just need to stop them being a breeding ground.

maximilianburke• 3 years ago

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.

com2kid2• 3 years ago

Unfortunate it is one of those "inquire now" things, if there was a "buy now" link I'd pick a few up right away.

joezydeco• 3 years ago

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?

jefftk12• 3 years ago

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.)

RenThraysk• 3 years ago

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)

lightedman4• 3 years ago

The performance drops off a cliff to tungsten-lamp levels starting in the UVB (290-310nm) range. We're still looking at state of the art at barely 3% efficiency for that and UVC.

apienx• 3 years ago

This group's notorious for shining UV at fashionable pathogens. https://www.nature.com/articles/s41598-020-67211-2

donsupreme• 3 years ago

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_forever4• 3 years ago

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• 3 years ago

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.

AuryGlenz• 3 years ago

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.

eutectic3• 3 years ago

I think it's extremely unlikely that rates of illness have gone up.

refurb2• 3 years ago

I would think that the past 500 years or so the amount of illness each person suffers has gone up exponentially.

It's actually the exact opposite? Improved hygiene and vaccination means rates of illness have dropped.

jefftk12• 3 years ago

Dereck Lowe ("In the Pipeline") has a good article on germicidal 222-nm: https://www.science.org/content/blog-post/two-twenty-two

londons_explore• 3 years ago

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.

lazide6• 3 years ago

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.

modestmc4• 3 years ago

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.

thfuran• 3 years ago

Human cells don't have cell walls.

bilsbie• 3 years ago

Remember when we needed germs to exercise our immune systems? Remember immune systems?

deegles4• 3 years ago

let me know how your exercise with avian flu, yellow fever, HIV, ebola, hepatitis, etc etc etc goes.

guntherhermann• 3 years ago

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

2muchcoffeeman• 3 years ago

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?

ChrisMarshallNY3• 3 years ago

ventilation in many buildings sucks

We've known that for a long time[0]. I have friends that are plumbers and HVAC people, that have to do strange stuff, by law.

[0] https://www.cdc.gov/legionella/index.html

marcosdumay• 3 years ago

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.

modestmc4• 3 years ago

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/

Animats2• 3 years ago

The holy grail for this technology is a Far-UVC Diode.

Right. Currently, 222nm lamps are gas-discharge tubes, and they cost far too much. There are fake 222nm LED lamps available online. There are also units that produce what Naomi Wu calls "homeopathic levels" of UV. Beware of scams.

If this is to go anywhere, a low-cost tester is needed. You can get a hand held UV spectrograph for about $3000, but that's more of a lab instrument. Something like a detector on a stick that lights up green for enough 222nm UV to be useful, and red for too much UV in dangerous parts of the spectrum.

One idea is to have a unit up near the ceiling that emits UV in a horizontal plane, so that air that makes it up to the ceiling gets sterilized. Convection, maybe with ceiling fan help, can move air through that region. But humans aren't up near the ceiling much, so they don't look into a UV source.

galangalalgol• 3 years ago

This still seems kinda scary. The scatter off the walls seems like it would be a problem for eyes or even skin over time. Would it generate ozone? What are the by-products of ionizing dust and what happens when you breath them?

SexyCyborg• 3 years ago

You can get 265-275nm LEDs- they are effective but you have to check them since there are constant scams.

https://twitter.com/RealSexyCyborg/status/154177301370350387...

You also have to dump a lot of heat so there's fan noise and Upper-Room GUV is already quite cheap so they aren't really game changers in that application- but they do work.

https://twitter.com/RealSexyCyborg/status/153744305018765722... https://twitter.com/RealSexyCyborg/status/153944537069847756...

222nm excimer lights are pretty costly per joule compared to 254-275nm given the 3,000hr or so lifespan of typical Chinese bulbs (although USHIO claims 10,000 is on the way) but from working with the factories they aren't quite as expensive as people think- the distributor markup is huge. You can also squeeze about 30% more out of them by switching to PTFE reflectors:

https://twitter.com/RealSexyCyborg/status/156236957519840051...

Best would be no reflector at all and pump as many joules into room air as we can with some air circulation, but right now we can only do that with unfiltered excimer lights- which aren't horrible but not something you'd want to sit with for several hours a day:

https://twitter.com/RealSexyCyborg/status/157656585826391244... https://twitter.com/RealSexyCyborg/status/159832965174278963...

Cylindrical 222nm cut filters would solve this but so far we can only get flat panes- and they are quite costly so building a square or triangular enclosure of filters costs more than you gain.

For what it's worth I make pretty extensive use of (filtered) 222nm- both portable and at home and I haven't caught COVID yet. Just an anecdote, but I've got no reason to stop using it- at least personally.

https://twitter.com/RealSexyCyborg/status/159942679977541222... https://twitter.com/RealSexyCyborg/status/159708372174773452... https://twitter.com/RealSexyCyborg/status/158850109792860160... https://twitter.com/RealSexyCyborg/status/161091221064529920...

The math on wearable Far-UVC didn't work out (exposure time is too short for the power, high power exceeds the TLV at that distance)- but it was a fun side project for a couple of days:

https://twitter.com/RealSexyCyborg/status/157297688745831219... https://twitter.com/RealSexyCyborg/status/158296013877611315...

As far as 222nm safety, I'm comfortable with it based on current data, used within recommended TLVs and have tested it on myself at length. But the one area I have concerns is folks with Lupus and other UV-sensitive immune disorders. It should be ok given that UVB seems to be the problem region, but we really have no information and I'd like some before any real widespread roll out of this technology.

https://twitter.com/RealSexyCyborg/status/155949983593741926...

throwaway2037• 3 years ago

Hat tip for the David Brenner link. The bottom of that page reads:

    Over the past six years, we have been working on a very exciting new approach to killing drug-resistant bacteria - superbugs- , as well as airborne viruses such as influenza, using a unique type of ultra-violet light. We have always known that ultraviolet light can efficiently kill all microbes, but conventional germicidal ultraviolet light is hazardous to our health, causing skin cancer and cataracts. We have identified a particular wavelength of UV light that has the best of both worlds - it's safe and it kills microbes - including superbugs.

While he doesn't say it directly, I guess he is talking about 222nm UV.

rngname22• 3 years ago

Wonder what it does to human health if the microbes on your skins surface are constantly exposed to Far-UV?

modestmc4• 3 years ago

Update: as a result of another comment, I stumbled into this: https://mdpi-res.com/d_attachment/ijms/ijms-23-09112/article...

My quick take on their experimental results is in the other comment, but in short it appears there will indeed be a trough of disillusionment somewhere down the line.

jefftk12• 3 years ago

Unless I'm misreading it, this paper looked at the effect on cells in isolation? But the reason we think 222nm is safe isn't that it has no effect on living cells, but that the living cells in our body are protected by a thin layer of dead cells that 222nm can't get through.

Here's the kind of paper I think is much more relevant, where they shined light into eyes directly: https://pubs.acs.org/doi/10.1021/acsphotonics.2c00041

ecesena• 3 years ago

This is a recent interesting paper: https://doi.org/10.1111/php.13767

Showing effectiveness on surfaces, while remaining safe for humans.

I’m following closely the development, it’s still extremely costly to make a product but hopefully will see more adoption in the near future, starting at enterprise level. I have a device in my home, planning to permanently install it in the entrance where we leave shoes & co.

Feel free to dm me if you’re hacking in the space, happy to chat more.

lstodd3• 3 years ago

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• 3 years ago

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.

deegles4• 3 years ago

The immune system is not a muscle that needs to be "exercised."

msandford3• 3 years ago

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.

lstodd3• 3 years ago

The UVC doesn't disrupt their metabolism or mutate their genetics subtly, it shreds their chemical bonds.

But it does -- this only depends on an prompt dose, at which you have exactly one chance. How can you guarantee a lethal dose (for any definition of lethal) for every single microorganism? Even hard gamma was adapted for, compared to that UV is nothing.

beambot• 3 years ago

As a safety & security robotics company, we looked at UVC applications early during the pandemic. We came to the same conclusions as Avidbots, which they published online:

https://avidbots.com/resources/what-you-need-to-know-about-u...

TLDR: The level of light insolation you need for disinfection makes them less useful for large area coverage and/or areas exposed to the public due to eye safety concerns.

ajmurmann3• 3 years ago

Note that this is about far UVC light. There were recent studies that showed that it's safe for humans and multi-celled organisms. The absorption by cells is so effective that the radiation is entirely absorpted by the top cell layer.

Plough_Jogger• 3 years ago

The team at R-Zero Systems has a Far-UV product on the market: https://rzero.com/vive/

refurb2• 3 years ago

https://www.biorxiv.org/content/10.1101/2022.02.22.481471v1....

However, cells exposed to 222-nm far UVC presented the highest degree of DNA damage as evidenced by yH2AX staining. Globally, these cells presented transcriptional changes in cell cycle and senescence pathways. Thus, the introduction of 222-nm far UVC lamps for disinfection purposes should be carefully considered and designed with the inherent dangers involved.

ajmurmann3• 3 years ago

I learned about this not long after it came out. That this didn't see a big push my the government during the pandemic and that practically nothing has been spent on ventilation to me are some of the most confidence shaking aspects of how the pandemic was handled

scotty793• 3 years ago

I think it's already used in some places: https://www.reddit.com/r/ZeroCovidCommunity/comments/10kbkhz...

nikolay• 3 years ago

I've been researching this and it's too bad that only a few companies produce these, and the pricing is outrageous! I understand they want to make sure only 222nm UVC is produced, but still, come on!

Disinfection with Far-UV (222 nm Ultraviolet light) (2020) [pdf]

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