Of all the lessons society failed to learn from 2020, the importance of clean air is perhaps the most disappointing.
I wear N95 masks on local trains, long distance trains, planes, buses (most of the time), and movie theaters when busy. The few times I haven’t, in particular local train (unfortunately, lots of unhealthy people) and Amtrak, I have gotten sick - strep and covid. Being sick is in some ways not a big deal, but is serious enough I will keep wearing the masks forever. I get sick far less often than my non mask wearing peers.
The tragedy is that the people operating these services - and schools and hospitals - should have installed filters and UV lamps to make this less unnecessary. At least planes have air circulation, the Amtrak trains are an absolute disaster.
Flu is spreading like wildfire right now. With the advent of these and other technologies, that is essentially an opt-in choice society is making. Totally unnecessary. You don’t have to stop many flu cases before a lamp pays for itself.
I incidentally reviewed my medical journal today and had ONE infection since 2018 (which in all likelihood was an enterovirus). ONE. What a bit of awareness will do for you and your immune system! Not just no sars2 but nothing else either.
TWO YEARS (not to mention a trillion and a half usd and eur) wasted on "handwashing" against an airborne virus plus all the other crap that came along with this betrayal or was it utter stupidity I still cant tell which.
I'm confused by the handwaving away of the ozone production. It's well established that ozone is toxic. If these are producing it - and it seems to be agreed upon that they are - that's an obvious issue. The suggestion that "you can just filter it with mechanical air filters (activated carbon)" seems strange because you can just filter viruses with mechanical air filters in that case...
I'm a big fan on the idea of improving air quality/reducing viral load in air to improve health. But I'd really prefer to see more of a push towards the "effective quiet (currently DIY) mechanical air filtration systems" the article links to then a technology with obvious and poorly quantified health risks.
>Does Aerolamp produce ozone?
>Yes - but only a very small amount
>Typical indoor ozone levels are 4-6 parts per billions (ppb), while average levels of outdoor ozone are 20-30 ppb - almost all indoor ozone comes from outdoors. Most likely, you will raise your indoor ozone levels much more by opening a window than by operating a far-UVC lamp.
>It's true that in a sealed chamber in a lab, typical far-UVC installations might produce significant (10s of ppb) ozone. However, our indoor spaces aren't sealed chambers. Both theoretical predictions and experimental evidence suggest that Aerolamp will raise indoor ozone levels by no more than 1-2 ppb. Expected ozone increase can also be simulated with Illuminate.
>However, we recognize that ozone is a pollutant, and recommend that Aerolamp should be used with portable air cleaners which include an activated carbon filter. Studies suggest that a single activated carbon filter is more than sufficient to mitigate any far-UVC derived ozone.
I agree that the filter thing doesn't make sense, but it does not seem like this product would meaningfully increase your ozone exposure.
Yes, you can point this specific UV wavelength at your skin and be fine. People have done extensive animal trials and it is not carcinogenic. Many people have been exposed to a lot of far UVC and nothing bad has happened to them.
Looking right at it might not be good for your eyes.
I feel confident for myself that far UVC is safe.
However, the environments I'd want to use this in are those where many people are gathered. I am not sure whether it is respectful/socially good to use this in those situations (given that far UVC products are not subject to any special regulatory review).
Edit for some additional thoughts:
How does this compare to a air filter?
Pros of UV:
- You are helping support R&D for this very important technology
- Even this Aerolamp DevKit is going to be more cost effective at addressing certain pathogens which are highly susceptible to UV, such as COVID. My guesstimate is that the highest capacity/$ off the shelf air purifier you can buy (https://www.cleanairkits.com/products/brisk-box-ultra-black) has about a third to half of the COVID-removing capacity/$ vs. the Aerolamp DevKit. Ditto for energy efficiency.
- Less maintenance vs. an air filter
- Quietest option
Cons of UV:
- Less energy and cost effective at addressing other microbes, particularly mold
- No ability to address dust, another very important air quality issue
I looked it up and Far-UVC (typically 222 nm) seems safe-ish. But how do you confirm it's not outputting 254 nm or other wavelengths in the UVA/B range? Seems likely to happen with sloppy production of sources. You really have to trust the filter on the light or verify the frequency somehow.
I've built 12V mercury vapor UV-C (254nm) lights for fluorescent mineral hunting, and that wavelength is quite harmful, requiring skin and eye protection. Mercury vapor lamps produce a spectrum of wavelengths, also in the visible spectrum, which gets filtered out since it distracts.
According to this [1] article, the 222nm range is safe for exposure, but the Krypton-Chloride bulb in the far-UVC lamp does also produce harmful wavelengths (256nm), therefore a filter is absolutely necessary. Thankfully simple plastics should work fine for that.
I would still be extremely careful deploying these lights in occupied spaces.
Edit: Come to think of it, filtering the harmful UVC (256nm) from KrCl excimer lamps with acrylic would probably also block the far-UVC. Which makes me wonder what material the filter is. Regular glass stops UVC, which is why UVC lamps are usually quartz or special glass formulations.
"What really needs to be understood is that an unfiltered 222nm Far-UV peak from any KrCl excimer lamp emits a wide band of wavelengths starting at 200nm, past the human safe zone of less than 230nm, all the way to the end of the UVC spectrum at 280nm -- with a very worrisome second harmonic peak at 256nm."
"the 222nm excimer lamp's second harmonic peak at 256nm exclusive to KrCl Far-UVC lights should be treated no different than the well-established carcinogenic hazards involved when using 254nm mercury-line UVC germicidal bulbs."
What took me by surprise (but really shouldn’t have) with my set of UV A, B, and C flashlights, is how much of the light can get reflected. Pointing at a rock and seeing a spot on my shirt light up was educational.
> At $500 this is out of (my) Christmas gift range, but I think we're now at the point where dances, churches, offices, rationalist group houses, schools, etc. should consider them.
One of the things in that list gives this away as something you'd see on HN.
that wavelength penetrates the skin. you need to be around 222nm for human safety
uviquity has prototypes of a 220nm solid state chip they’ll commercialize next year (we’re an investor). a single far-uvc photon will destroy the covid virus.
The advantage of far UVC over other UV air cleaning solutions is that it doesn't need to be ducted. This means that you can kill microbes right when they leave someone's mouth - you don't need to wait for them to be sucked through an air handler.
I'm curious if plastics embrittlement is a problem with Far-UVC. I recently was putting a large evaporative humidifier [1] through its paces for someone to get my opinion, and a challenge was that you had to clean the water tank that was the foundation of the unit fairly frequently (every few days). I provided feedback to the manufacturer that a far UVC bulb in the tank might be useful for reducing cleaning intervals.
For use cases where the emissions are contained (HVAC, water tanks, etc), I think it's a slam dunk from an electronic antiseptic perspective. UV is somewhat common in water filtration today, but perhaps an improvement is possible if these bulbs last longer than existing UV solutions.
(I do not recommend the humidifier by the way, simply too much work to keep the water tank and the evaporation panels clean, I recommend an ultrasonic version instead)
A ducted system seems like it kills a lot of the pros of this system compared to just putting an (effective, i.e. merv-13+) air filter in the ducted system to catch the viruses. And also other things that are bad for you like particles small enough to get where they shouldn't in your lungs.
This absolutely depends on the frequency of UVC and the intensity of the lamp. The lamps this post links such as https://aerolamp.net are putting out 222-nm, which is much safer than longer UVC wavelengths and the intensity is well under TLV when placed 8.5ft up (or higher).
They can leak into higher wavelengths. You are really putting a whole lot of trust in manufacturers if you are sitting underneath one of these for decades with unprotected eyes. Not a risk I would take personally (I have glaucoma already, so I'm a bit more sensitive than the average person about eye health)
> Far-UVC is a type of ultraviolet light emitted at a 222 nm wavelength that effectively deactivates microorganisms. Unlike traditional UVC light at 254 nm, Far-UVC doesn’t penetrate the outer dead layer of skin or the outer layer of the cornea, making it safe for use around people while maintaining powerful germicidal properties.
> The 222 nm wavelength is unique in its ability to decontaminate without causing harm when used within regulatory limits. Unlike longer UV wavelengths, it interacts only with the outermost layers of the skin and eyes, which naturally renew themselves. This makes it ideal for continuous decontamination in occupied spaces, as confirmed by the 36-month clinical study showing no adverse effects even after daily exposure.
Interesting study. Only four people though, and the lamps were "carefully calibrated" so exposure was within a safety threshold. I've seen some lamps have safety interlocks that attempt to turn off the light if people get too close. I don't think UVC will be practical for most settings as long as it needs this kind of caution.
If we could establish a higher safety threshold so that we could be sure it wouldn't harm humans even if they were very close to the lamp, that would be great. Then we could deploy it in almost any public or private space.
I mean, UV light is carcinogenic, and environments that are way too clean, are fine for surgery or manufacturing semiconductors, but for most humans (specially children) they can be counter-productive.
The immune system needs something to train on and fight, otherwise you end up with autoimmune diseases and all sorts of crap.
We're essentially walking ecosystems that can easily be imbalanced.
Far UVC is carcinogenic when it reaches living tissue. However, it has a very short mean free path so it doesn't, generally, reach the growing layer of skin. It's less obvious whether exposed mucus membranes (lips, nose, tongue) or the eyes are affected. It probably doesn't reach the lens of the eye, which is good.
The best training for immune robustness is going outside and get exposure to a wide range of stuff. But for indoor spaces, air quality is going to be dominated by the microbes and viruses of the people in the space itself. For public spaces and shared residential spaces with poor airflow this would be great - grocery stores, nursing homes, etc. For condos, apartments, SFH, etc. it's probably less necessary, but probably wouldn't hurt. Or nice to have when company comes over, or someone in the house is sick and "polluting" the air.
Of all the lessons society failed to learn from 2020, the importance of clean air is perhaps the most disappointing.
I wear N95 masks on local trains, long distance trains, planes, buses (most of the time), and movie theaters when busy. The few times I haven’t, in particular local train (unfortunately, lots of unhealthy people) and Amtrak, I have gotten sick - strep and covid. Being sick is in some ways not a big deal, but is serious enough I will keep wearing the masks forever. I get sick far less often than my non mask wearing peers.
The tragedy is that the people operating these services - and schools and hospitals - should have installed filters and UV lamps to make this less unnecessary. At least planes have air circulation, the Amtrak trains are an absolute disaster.
Flu is spreading like wildfire right now. With the advent of these and other technologies, that is essentially an opt-in choice society is making. Totally unnecessary. You don’t have to stop many flu cases before a lamp pays for itself.
When Elon the Shithead announced the Tesla Biohazard filter for China, I was annoyed.
Our Public Transports AC is so shit, that in a hot summer, the outside is cooler than the full SBahn.
And a single Car! Had such a good air filter in comparision.
I primarily communte by car now after the office moved and i'm def less often sick.
I incidentally reviewed my medical journal today and had ONE infection since 2018 (which in all likelihood was an enterovirus). ONE. What a bit of awareness will do for you and your immune system! Not just no sars2 but nothing else either.
TWO YEARS (not to mention a trillion and a half usd and eur) wasted on "handwashing" against an airborne virus plus all the other crap that came along with this betrayal or was it utter stupidity I still cant tell which.
I'm confused by the handwaving away of the ozone production. It's well established that ozone is toxic. If these are producing it - and it seems to be agreed upon that they are - that's an obvious issue. The suggestion that "you can just filter it with mechanical air filters (activated carbon)" seems strange because you can just filter viruses with mechanical air filters in that case...
I'm a big fan on the idea of improving air quality/reducing viral load in air to improve health. But I'd really prefer to see more of a push towards the "effective quiet (currently DIY) mechanical air filtration systems" the article links to then a technology with obvious and poorly quantified health risks.
From Aerolamps website:
>Does Aerolamp produce ozone? >Yes - but only a very small amount
>Typical indoor ozone levels are 4-6 parts per billions (ppb), while average levels of outdoor ozone are 20-30 ppb - almost all indoor ozone comes from outdoors. Most likely, you will raise your indoor ozone levels much more by opening a window than by operating a far-UVC lamp.
>It's true that in a sealed chamber in a lab, typical far-UVC installations might produce significant (10s of ppb) ozone. However, our indoor spaces aren't sealed chambers. Both theoretical predictions and experimental evidence suggest that Aerolamp will raise indoor ozone levels by no more than 1-2 ppb. Expected ozone increase can also be simulated with Illuminate.
>However, we recognize that ozone is a pollutant, and recommend that Aerolamp should be used with portable air cleaners which include an activated carbon filter. Studies suggest that a single activated carbon filter is more than sufficient to mitigate any far-UVC derived ozone.
I agree that the filter thing doesn't make sense, but it does not seem like this product would meaningfully increase your ozone exposure.
Yes, you can point this specific UV wavelength at your skin and be fine. People have done extensive animal trials and it is not carcinogenic. Many people have been exposed to a lot of far UVC and nothing bad has happened to them.
Looking right at it might not be good for your eyes.
I feel confident for myself that far UVC is safe.
However, the environments I'd want to use this in are those where many people are gathered. I am not sure whether it is respectful/socially good to use this in those situations (given that far UVC products are not subject to any special regulatory review).
Edit for some additional thoughts:
How does this compare to a air filter?
Pros of UV:
- You are helping support R&D for this very important technology
- Even this Aerolamp DevKit is going to be more cost effective at addressing certain pathogens which are highly susceptible to UV, such as COVID. My guesstimate is that the highest capacity/$ off the shelf air purifier you can buy (https://www.cleanairkits.com/products/brisk-box-ultra-black) has about a third to half of the COVID-removing capacity/$ vs. the Aerolamp DevKit. Ditto for energy efficiency.
- Less maintenance vs. an air filter
- Quietest option
Cons of UV:
- Less energy and cost effective at addressing other microbes, particularly mold
- No ability to address dust, another very important air quality issue
- May make others feel uncomfortable
I looked it up and Far-UVC (typically 222 nm) seems safe-ish. But how do you confirm it's not outputting 254 nm or other wavelengths in the UVA/B range? Seems likely to happen with sloppy production of sources. You really have to trust the filter on the light or verify the frequency somehow.
I've built 12V mercury vapor UV-C (254nm) lights for fluorescent mineral hunting, and that wavelength is quite harmful, requiring skin and eye protection. Mercury vapor lamps produce a spectrum of wavelengths, also in the visible spectrum, which gets filtered out since it distracts.
According to this [1] article, the 222nm range is safe for exposure, but the Krypton-Chloride bulb in the far-UVC lamp does also produce harmful wavelengths (256nm), therefore a filter is absolutely necessary. Thankfully simple plastics should work fine for that.
I would still be extremely careful deploying these lights in occupied spaces.
Edit: Come to think of it, filtering the harmful UVC (256nm) from KrCl excimer lamps with acrylic would probably also block the far-UVC. Which makes me wonder what material the filter is. Regular glass stops UVC, which is why UVC lamps are usually quartz or special glass formulations.
"What really needs to be understood is that an unfiltered 222nm Far-UV peak from any KrCl excimer lamp emits a wide band of wavelengths starting at 200nm, past the human safe zone of less than 230nm, all the way to the end of the UVC spectrum at 280nm -- with a very worrisome second harmonic peak at 256nm."
"the 222nm excimer lamp's second harmonic peak at 256nm exclusive to KrCl Far-UVC lights should be treated no different than the well-established carcinogenic hazards involved when using 254nm mercury-line UVC germicidal bulbs."
[1] https://www.prweb.com/releases/222-nm-far-uvc-cancer-risk-wi...
What took me by surprise (but really shouldn’t have) with my set of UV A, B, and C flashlights, is how much of the light can get reflected. Pointing at a rock and seeing a spot on my shirt light up was educational.
There are lots of far-UV germicidal lamps. Here's one, from Shenzhen.[1] (This is Naomi Wu's business.)
There are lot of fake ones out there. Especially ones with LEDs. Nobody has a 222nm LED with enough power for this yet.
Someone should make a simple tester. Something that's on the end of a stick, you hold it up near the ceiling, and it lights up:
- Green - enough 222nm light to be effective, not too much other UV.
- Red - too much other UV, light is dangerous.
- Yellow - only "homeopathic" levels of 222nm, ineffective.
You can buy NBS-traceable UV meters, and even a spectrometer, but they're expensive.
[1] https://cybernightmarket.com/products/nukit-lantern-far-uvc-...
> At $500 this is out of (my) Christmas gift range, but I think we're now at the point where dances, churches, offices, rationalist group houses, schools, etc. should consider them.
One of the things in that list gives this away as something you'd see on HN.
You can buy UVC LEDs (255nm) for fairly cheap now. $20 or less
that wavelength penetrates the skin. you need to be around 222nm for human safety
uviquity has prototypes of a 220nm solid state chip they’ll commercialize next year (we’re an investor). a single far-uvc photon will destroy the covid virus.
https://uviquity.com/
Yes, however the safety-profile is quite the opposite to 222nm.
https://www.larsonelectronics.com/news/1763
https://uvmedico.com/far-uvc-light
Do you know a good source for finding the latest, most efficient LEDs for DIY projects?
This is Far-UVC (typically 222 nm). Regular UVC can cause eye damage.
This is an affordable UVC flashlight (buy filter separately due to US patent bs):
https://convoylight.com/products/gray-c8-uvc-255nm-uvb-310nm
Feels like v2 of this will be “ducted” in that it lives next to your air handler and comes on when you are circulating air.
(Like a reef tank sterilizer)
The advantage of far UVC over other UV air cleaning solutions is that it doesn't need to be ducted. This means that you can kill microbes right when they leave someone's mouth - you don't need to wait for them to be sucked through an air handler.
I'm curious if plastics embrittlement is a problem with Far-UVC. I recently was putting a large evaporative humidifier [1] through its paces for someone to get my opinion, and a challenge was that you had to clean the water tank that was the foundation of the unit fairly frequently (every few days). I provided feedback to the manufacturer that a far UVC bulb in the tank might be useful for reducing cleaning intervals.
For use cases where the emissions are contained (HVAC, water tanks, etc), I think it's a slam dunk from an electronic antiseptic perspective. UV is somewhat common in water filtration today, but perhaps an improvement is possible if these bulbs last longer than existing UV solutions.
[1] https://levoit.com/collections/humidifiers-diffusers/product...
(I do not recommend the humidifier by the way, simply too much work to keep the water tank and the evaporation panels clean, I recommend an ultrasonic version instead)
I do not believe that there is a good understanding of the impact of far-uvc on plastic embrittlement.
Delightful, an experiment to be run!
It doesn't have to be, but you can avoid any concerns about looking into it or affecting the light quality in the room by doing so.
If you were going to duct it then why wouldn't you just use regular UVC? Much cheaper.
Fair point.
Ducted UV systems for your HVAC exist now, and don't need to bother with the being UVC since the UV doesn't leave the system.
If I recall correctly my furnace guy quoted me less than $2k for a whole house system that attaches to the air intake on my furnace.
A ducted system seems like it kills a lot of the pros of this system compared to just putting an (effective, i.e. merv-13+) air filter in the ducted system to catch the viruses. And also other things that are bad for you like particles small enough to get where they shouldn't in your lungs.
no way you're supposed to point it down, right?
Aerolamp insists that it's supposed to be pointed directly at "where people will spend time in the room", including tilting it down.
Leaving UVC sources exposed to eyesight is completely irresponsible. Please don't do this.
(author)
This absolutely depends on the frequency of UVC and the intensity of the lamp. The lamps this post links such as https://aerolamp.net are putting out 222-nm, which is much safer than longer UVC wavelengths and the intensity is well under TLV when placed 8.5ft up (or higher).
See https://www.faruvc.org for more on eye safety.
They can leak into higher wavelengths. You are really putting a whole lot of trust in manufacturers if you are sitting underneath one of these for decades with unprotected eyes. Not a risk I would take personally (I have glaucoma already, so I'm a bit more sensitive than the average person about eye health)
Ah nice, their data sheet has a spectrum. Kind of odd that they don't market the "we filter out the harmful parts" feature more prominently.
Far-UVC and Eye Safety: Findings from a 36-Month Study - https://uvmedico.com/news/far-uvc-and-eye-safety - January 16th, 2025
> Far-UVC is a type of ultraviolet light emitted at a 222 nm wavelength that effectively deactivates microorganisms. Unlike traditional UVC light at 254 nm, Far-UVC doesn’t penetrate the outer dead layer of skin or the outer layer of the cornea, making it safe for use around people while maintaining powerful germicidal properties.
> The 222 nm wavelength is unique in its ability to decontaminate without causing harm when used within regulatory limits. Unlike longer UV wavelengths, it interacts only with the outermost layers of the skin and eyes, which naturally renew themselves. This makes it ideal for continuous decontamination in occupied spaces, as confirmed by the 36-month clinical study showing no adverse effects even after daily exposure.
References:
https://www.faruvc.org/ (disclosure: this is published by the same author as this post)
Sugihara K, Kaidzu S, Sasaki M, Ichioka S, Sano I, Hara K, Tanito M. Ocular safety of 222-nm far-ultraviolet-c full-room germicidal irradiation: A 36-month clinical observation. Photochem Photobiol. 2024 Dec 10. https://doi.org/10.1111/php.14052 Epub ahead of print. PMID: 39659140. https://onlinelibrary.wiley.com/doi/10.1111/php.14052
Sugihara K, Kaidzu S, Sasaki M, Tanito M. Interventional human ocular safety experiments for 222-nm far-ultraviolet-C lamp irradiation. Photochem Photobiol. 2024 Aug 19. https://doi.org/10.1111/php.14016 Epub ahead of print. PMID: 39161063. https://onlinelibrary.wiley.com/doi/10.1111/php.14016
Buonanno M, Hashmi R, Petersen CE, Tang Z, Welch D, Shuryak I, Brenner DJ. Wavelength-dependent DNA damage induced by single wavelengths of UV-C radiation (215 to 255 nm) in a human cornea model. Sci Rep. 2025 Jan 2;15(1):252. https://doi.org/10.1038/s41598-024-84196-4 PMID: 39747969; PMCID: PMC11696903. https://www.nature.com/articles/s41598-024-84196-4
Interesting study. Only four people though, and the lamps were "carefully calibrated" so exposure was within a safety threshold. I've seen some lamps have safety interlocks that attempt to turn off the light if people get too close. I don't think UVC will be practical for most settings as long as it needs this kind of caution.
If we could establish a higher safety threshold so that we could be sure it wouldn't harm humans even if they were very close to the lamp, that would be great. Then we could deploy it in almost any public or private space.
I think that blog post is mostly just an AI summary of one or more of those studies.
Noted, it was included for completeness after I had independently found the resources I enumerate.
FYI, all three of the studies are funded by UV light manufacturers: Ushio Inc (first two, 100%), and LumenLabs (last one, partially).
It feels like this would backfire.
I mean, UV light is carcinogenic, and environments that are way too clean, are fine for surgery or manufacturing semiconductors, but for most humans (specially children) they can be counter-productive.
The immune system needs something to train on and fight, otherwise you end up with autoimmune diseases and all sorts of crap.
We're essentially walking ecosystems that can easily be imbalanced.
Far UVC is not carcinogenic (most UV is, this is just a specific wavelength that isn't).
Ideally you'd want to use these lamps in environments that our immune systems didn't evolve for, like crowded conference rooms and school classrooms.
Far UVC is carcinogenic when it reaches living tissue. However, it has a very short mean free path so it doesn't, generally, reach the growing layer of skin. It's less obvious whether exposed mucus membranes (lips, nose, tongue) or the eyes are affected. It probably doesn't reach the lens of the eye, which is good.
I think that is the same thing as saying that Far UVC is non-carcinogenic.
I actually read it as saying far UVC is probably carcinogenic for specific areas of your body (lips, maybe eyes).
I don't know if that's true, but it's what GP suggests to me.
The best training for immune robustness is going outside and get exposure to a wide range of stuff. But for indoor spaces, air quality is going to be dominated by the microbes and viruses of the people in the space itself. For public spaces and shared residential spaces with poor airflow this would be great - grocery stores, nursing homes, etc. For condos, apartments, SFH, etc. it's probably less necessary, but probably wouldn't hurt. Or nice to have when company comes over, or someone in the house is sick and "polluting" the air.
>> The immune system needs something to train on and fight, otherwise you end up with autoimmune diseases and all sorts of crap.
If you want to train your childrens' immune system, get a dog. Don't intentionally expose them to pathenogenic viruses like COVID or the flu. https://www.science.org/content/article/want-fight-allergies...