11 ms·

Germicidal UV could make airborne diseases as rare as those carried by water

118 points by venkii 1y ago

more_corn 1y ago
UV causes melanoma which is why we wear sunscreen.
- Retz4o4 1y ago
  Far UVC?
- wpm 1y ago
  The article explains this concern in the 3rd and 4th paragraph.
- nikolay 1y ago
  Wong UV wavelength range! 222nm is safe for humans [0]! [0]: https://www.nature.com/articles/s41598-020-67211-2 https://www.nature.com/articles/s41598-020-67211-2
- pazimzadeh 1y ago
  too much UV all at once, you mean. melanoma is not common and face and arms - the regions which receive the most sunlight a moderate amount of UV stimulates vitamin D production, suppresses inflammation, and turns on DNA repair pathways
  - bschwarz 1y ago
    This moderate amount of UV is enough to accelerate skin aging which is why we wear sunscreen.
    - pazimzadeh 1y ago
      The topic was melanoma incidence, not skin aging. But even for skin aging things aren't that simple, though sunscreen companies would love you to think that. UV light is a treatment for psoriasis, eczema, and many other skin conditions. And vitamin D improves symptoms/reduces incidence of "hypertension, cardiovascular disease, stroke, breast cancer, colorectal cancer, metabolic syndrome, type 2 diabetes, obesity, multiple sclerosis, type 1 diabetes, rheumatoid arthritis, Alzheimer’s disease, autism, schizophrenia, asthma, preterm birth, maternal mortality, myopia and COVID-19" (a lot of these are aging related). Most studies on UV light/vitamin D supplementation have been done in mice, which are nocturnal and don't get the same benefits as us from sunlight. Here's a recent article in pigs: UV light exposure versus vitamin D supplementation: A comparison of health benefits and vitamin D metabolism in a pig model https://www.sciencedirect.com/science/article/pii/S0955286324001773 https://www.sciencedirect.com/science/article/pii/S095528632... Here's a helpful review of the topic: Are Vitamin D Supplements an Adequate Substitute for Sun Exposure? https://esmed.org/MRA/mra/article/view/3635 https://esmed.org/MRA/mra/article/view/3635 In this paper we review the current state of the science on this subject and conclude that vitamin D supplements are not an adequate substitute for sun exposure for attenuation of most of these diseases and adverse health effects, particularly hypertension and cardiovascular disease, and should not be recommended in lieu of sun exposure to patients presenting with low levels of serum 25(OH)D. Vitamin D supplementation for such patients could even be harmful, because it will raise patients’ serum 25(OH)D levels, thereby giving patients a false sense of security and obscuring the best available metric for insufficient sun exposure.
Animats 1y ago
If only 222nm UV lamps didn't cost so much.[1] [1] https://cybernightmarket.com/products/mini-far-uvc-lights-set https://cybernightmarket.com/products/mini-far-uvc-lights-se...
- mahrain 1y ago
  Still risky, these typical Chinese devices don't come with a filter, so harmful wavelengths will still be present. The filter is actually the expensive part. Also, such a small component would need sufficient cooling as these operate at 4kV. I don't really see this here, so it makes me doubt these devices.
mahrain 1y ago
I have worked on such systems at Signify: There are numerous barriers to wider adoption except for very high risk situations. For instance: there have yet to be lawsuits to determine the risk of exposing people to UV. As you see in the comments below, any "UV" is considered dangerous by people not aware of the biological effects of various wavelenghts. Besides this, excimer lamps have a low expected lifetime, of both the light source as well as the filter due to the high energy in the UV photons. This makes replacement (and maintenance cost) a real risk. This could be remedied by similar wavelength LEDs from companies like CrystalIS but these are expensive and very low power (only work germicidal on a short distance). Prof. Brenner at Columbia University has first foreseen applications of 222nm in operating rooms, to prevent infection during surgery. On the whole, it would need significant investment in both research, certification and risk analysis for this to become commercially viable, so while some of the technology is there, the market demand so far just is not -- post-pandemic.
- unsnap_biceps 1y ago
  Every year our HVAC company tries to sell us UV lights for the HVAC system. They claim it's only about $1500 to install. Are these snake oil?
  - mahrain 1y ago
    Mostly used to eliminate or reduce mould growth on the inverter? If HVAC is taking air in or blowing air out, there really wouldn't be a point disinfecting the air. If it's re-circulating, it could reduce the spread of germs room to room as has been shown during the pandemic in elderly care facilities. That would be the only use-case I see.
    - unsnap_biceps 1y ago
      they claim it would reduce growths on the coils but also eliminate mold and bacteria spores. Our system is a re-circulating system. One large intake in the center of the house and out flows in individual rooms.
toast0 1y ago
Seems like this has potential, but uv exposure is potentially problematic to humans, and definitely problematic to man surfaces and some plants. Limiting the wavelength helps with humans, but adds a lot of cost. It might be effective to have a box that draws in air (with a fan, most likely) and the UV source shines within. The inputs and outputs would need to have a few turns and have surface treatments to reduce the amount of uv ligh that can escape. You would have some fan noise though.
- mahrain 1y ago
  This is correct and such systems do exist, sometimes combined with sources of ions and HEPA filters. However if you're already drawing air out of the room, it's easier to just filter it with HEPA than dealing with the additional complexity of UV lights (deterioration, energy consumption, replacement).
  - schiffern 1y ago
    HEPA filters also have deterioration, energy consumption (pressure drop ain't free), and replacement. HEPA is a mature technology with no big improvement curve, but UV treatment is seeing progress.
wiseowise 1y ago
ASTRAL DID IT AGAIN!!!1
vintermann 1y ago
No mention of ozone. The more directly dangerous 254nm UV light has the advantage that it doesn't create ozone. Viruses and bacteria aren't the only bad things you don't want in your air. Ozone is thought to be a carcinogen in its own right and aggravate the health effects of particulate pollution. We want filtering and air circulation anyway, we don't want anything that makes it worse. The consumer electronics industry is all too willing to try to sell us things that make our problems worse, such as ultrasonic humidifiers, or ionizing air purifiers with special chambers for your aromatherapy oils, so it's best to be careful.
- mahrain 1y ago
  Could accumulate in an isolated room, but following normal building ventilation standards, really shouldn't be an issue as shown by Brenner in 2023: https://pubmed.ncbi.nlm.nih.gov/38037431/ https://pubmed.ncbi.nlm.nih.gov/38037431/
  - harvie 1y ago
    article specificaly mentions rooms with poor ventilation. if you have proper ventilation, then you don't need this system in the first place, because you will get ouside air UV sterilised by the sun...
- scns 1y ago
  > things that make our problems worse, such as ultrasonic humidifiers, or ionizing air purifiers What is bad about these?
  - vintermann 1y ago
    Ultrasonic humidifiers require ridiculously clean water. Even regular distilled water is scarcely clean enough. You need to clean the water tank ridiculously well, ridiculously often. No one actually uses an ultrasonic humidifier like it's "supposed" to be used. When the water isn't industrially clean, everything dissolved in it is turned very efficiently into tiny particles. You'll get a fine white mineral dust everywhere. Ionizing air purifiers make ozone and the makers claim either that it's a good thing or that it's too little to worry about. The first is wrong, the second is a bad sell because the thing it's supposed to be removing is also (by itself) not a big health risk on any single day; the health benefit from removing particles is likely eaten up by the negative health effects of the ozone. You can clean air without ionization, so why? As far as I can tell, it's a pure marketing gimmick, the need to seem high-tech outweighs the actual utility of the thing. (That's also probably why ultrasonic humidifiers are popular, you can see the fog)
ur-whale 1y ago
Wont micro-organisms quickly adapt and start producing UV resistant strains?
- VMG 1y ago
  There is a giant orb in the sky that emits UV and has for billions of years. I think the microbes are still trying to figure this one out.
  - mahrain 1y ago
    You are correct, however most of the harmful rays get filtered out in the upper atmosphere. Far-UV doesn't reach Earth, only UV-A and small amounts of UV-B (if the ozone layer is more or less intact that is!).
  - Qem 1y ago
    > I think the microbes are still trying to figure this one out. They mostly figured it out a couple billion years ago. Cyanobacteria oxidized Earth's surface until the atmosphere was flooded with molecular oxigen, that gets turned to ozone in the stratosphere, filtering most UV. Pretty large engineering feat for a bunch of microbes.
- mahrain 1y ago
  The germicidal effect is a function of the DNA being directly affected by the UV rays and breaking apart. Very few organisms exist that could adapt, this would require external shells, skin etc, not typically found in microorganisms.
  - jiehong 1y ago
    Tardigrades and organisms ables to survive space by having more efficient DNA repair mechanisms. Unlikely for most organism, true
- ljsprague 1y ago
  I also wonder about stuff like this. I think some things are just a bridge-too-far for organisms to evolve protections against. For instance, are we worried about using too much bleach? Or stepping on cockroaches?
mriet 1y ago
Idiotic and massively overlooks/underestimates how complex biology is. What about beneficial and neutral but important bacteria and viruses? "Air" is actually a complex soup of all types of things. This like applying HCl to a skin infection.
- pjc50 1y ago
  > What about beneficial and neutral but important bacteria and viruses? Such as what? There are some located in the gut, but pretty much everything else out there is in conflict with our immune system.
  - pazimzadeh 1y ago
    where are you getting this info? almost every mucosal surface has commensal bacteria which can provide colonization resistance by other bacteria. lungs, skin, vagina, etc..
- mahrain 1y ago
  Studying a building's microbiome is really a new field. What happens to people if offices become boxes of sterile air and -surfaces? We don't know.
- Llamamoe 1y ago
  I would consider it unlikely that airborne germs form a significant input to our microbiomes. For example, the gut microbiome is in flux for about the first 3 years of life, and thereafter it's mostly only the relative abundances of different microbes that shift in response to diet, you need something like antibiotics or severe diarrhea to actually induce permanent changes (usually for the worse). Compared to that, there really aren't many microbes in the air. For children, it could very possibly be bad, but even then I'd expect most of their microbial input to come from their parents, food, and surfaces. Which are already grossly deficient compared to old-school rural settings, but I'm not sure if germicidal UV would make it worse.
- bondarchuk 1y ago
  I doubt it would be a problem for the microbiome [1] but I would worry about the immune system. Would being inside in sterilized air all the time mean you can't go outside or into a forest without getting really sick? [1] but who am I, it would still be worthwhile to check obviously
eythian 1y ago
It's a minor point, but it's interesting that they used having AC as a proxy for mechanical ventilation and conclude that it's rare in Europe. At least where I live (NL), mechanical ventilation is common - I think required in some situations - even though AC isn't. It's basically a fancy extractor fan that pumps air outside, so bringing fresh air in. That said, you'd need to reverse that flow to add filters.
- lm28469 1y ago
  Yes, few people have AC but almost everyone living in a semi recent place has mechanical ventilation in, at the very least, kitchen and bathroom, which thanks to physics renew the air of the entire falt/house.
owenversteeg 1y ago
Interesting, but I use a much more powerful germicidal UV source. Because of the power requirements it uses a fusion energy source located ~150M km away. (sunlight in fresh air.) In fairness to the article, ventilation was mentioned, but also quickly dismissed. The 60% efficiency figure quoted for ERV is also a bit on the low side for many contexts. And sure, ERV fans themselves use some power (say 50W) but that's about what you'd use in a decent size room with some UV lamps and a fan.
andrewrn 1y ago
I worked on a 254nm UVC fungicide system at an agricultural robotics startup. For some fungal pests like powdery mildew, there’s growing evidence that irradiating the crops at night (when the fungus has its UV defenses down), can effectively manage fungus outbreaks and save crops yields. This was specifically strawberries. I had to do a bunch of safety research and testing. We had some grower partners experimenting with it too and they had their workers operate the system without any coverings and everyone got sunburn. Unbelievable. Another startup working on this right now is TRIC robotics.

118 points by venkii 1y ago

more_corn 1y ago

UV causes melanoma which is why we wear sunscreen.

Retz4o4 1y ago
Far UVC?
wpm 1y ago
The article explains this concern in the 3rd and 4th paragraph.
nikolay 1y ago
Wong UV wavelength range! 222nm is safe for humans [0]! [0]: https://www.nature.com/articles/s41598-020-67211-2 https://www.nature.com/articles/s41598-020-67211-2
pazimzadeh 1y ago
too much UV all at once, you mean. melanoma is not common and face and arms - the regions which receive the most sunlight a moderate amount of UV stimulates vitamin D production, suppresses inflammation, and turns on DNA repair pathways
- bschwarz 1y ago
  This moderate amount of UV is enough to accelerate skin aging which is why we wear sunscreen.
  - pazimzadeh 1y ago
    The topic was melanoma incidence, not skin aging. But even for skin aging things aren't that simple, though sunscreen companies would love you to think that. UV light is a treatment for psoriasis, eczema, and many other skin conditions. And vitamin D improves symptoms/reduces incidence of "hypertension, cardiovascular disease, stroke, breast cancer, colorectal cancer, metabolic syndrome, type 2 diabetes, obesity, multiple sclerosis, type 1 diabetes, rheumatoid arthritis, Alzheimer’s disease, autism, schizophrenia, asthma, preterm birth, maternal mortality, myopia and COVID-19" (a lot of these are aging related). Most studies on UV light/vitamin D supplementation have been done in mice, which are nocturnal and don't get the same benefits as us from sunlight. Here's a recent article in pigs: UV light exposure versus vitamin D supplementation: A comparison of health benefits and vitamin D metabolism in a pig model https://www.sciencedirect.com/science/article/pii/S0955286324001773 https://www.sciencedirect.com/science/article/pii/S095528632... Here's a helpful review of the topic: Are Vitamin D Supplements an Adequate Substitute for Sun Exposure? https://esmed.org/MRA/mra/article/view/3635 https://esmed.org/MRA/mra/article/view/3635 In this paper we review the current state of the science on this subject and conclude that vitamin D supplements are not an adequate substitute for sun exposure for attenuation of most of these diseases and adverse health effects, particularly hypertension and cardiovascular disease, and should not be recommended in lieu of sun exposure to patients presenting with low levels of serum 25(OH)D. Vitamin D supplementation for such patients could even be harmful, because it will raise patients’ serum 25(OH)D levels, thereby giving patients a false sense of security and obscuring the best available metric for insufficient sun exposure.

Animats 1y ago

If only 222nm UV lamps didn't cost so much.[1] [1] https://cybernightmarket.com/products/mini-far-uvc-lights-set https://cybernightmarket.com/products/mini-far-uvc-lights-se...

mahrain 1y ago
Still risky, these typical Chinese devices don't come with a filter, so harmful wavelengths will still be present. The filter is actually the expensive part. Also, such a small component would need sufficient cooling as these operate at 4kV. I don't really see this here, so it makes me doubt these devices.

mahrain 1y ago

I have worked on such systems at Signify: There are numerous barriers to wider adoption except for very high risk situations. For instance: there have yet to be lawsuits to determine the risk of exposing people to UV. As you see in the comments below, any "UV" is considered dangerous by people not aware of the biological effects of various wavelenghts. Besides this, excimer lamps have a low expected lifetime, of both the light source as well as the filter due to the high energy in the UV photons. This makes replacement (and maintenance cost) a real risk. This could be remedied by similar wavelength LEDs from companies like CrystalIS but these are expensive and very low power (only work germicidal on a short distance). Prof. Brenner at Columbia University has first foreseen applications of 222nm in operating rooms, to prevent infection during surgery. On the whole, it would need significant investment in both research, certification and risk analysis for this to become commercially viable, so while some of the technology is there, the market demand so far just is not -- post-pandemic.

unsnap_biceps 1y ago
Every year our HVAC company tries to sell us UV lights for the HVAC system. They claim it's only about $1500 to install. Are these snake oil?
- mahrain 1y ago
  Mostly used to eliminate or reduce mould growth on the inverter? If HVAC is taking air in or blowing air out, there really wouldn't be a point disinfecting the air. If it's re-circulating, it could reduce the spread of germs room to room as has been shown during the pandemic in elderly care facilities. That would be the only use-case I see.
  - unsnap_biceps 1y ago
    they claim it would reduce growths on the coils but also eliminate mold and bacteria spores. Our system is a re-circulating system. One large intake in the center of the house and out flows in individual rooms.

toast0 1y ago

Seems like this has potential, but uv exposure is potentially problematic to humans, and definitely problematic to man surfaces and some plants. Limiting the wavelength helps with humans, but adds a lot of cost. It might be effective to have a box that draws in air (with a fan, most likely) and the UV source shines within. The inputs and outputs would need to have a few turns and have surface treatments to reduce the amount of uv ligh that can escape. You would have some fan noise though.

mahrain 1y ago
This is correct and such systems do exist, sometimes combined with sources of ions and HEPA filters. However if you're already drawing air out of the room, it's easier to just filter it with HEPA than dealing with the additional complexity of UV lights (deterioration, energy consumption, replacement).
- schiffern 1y ago
  HEPA filters also have deterioration, energy consumption (pressure drop ain't free), and replacement. HEPA is a mature technology with no big improvement curve, but UV treatment is seeing progress.

wiseowise 1y ago

ASTRAL DID IT AGAIN!!!1

vintermann 1y ago

No mention of ozone. The more directly dangerous 254nm UV light has the advantage that it doesn't create ozone. Viruses and bacteria aren't the only bad things you don't want in your air. Ozone is thought to be a carcinogen in its own right and aggravate the health effects of particulate pollution. We want filtering and air circulation anyway, we don't want anything that makes it worse. The consumer electronics industry is all too willing to try to sell us things that make our problems worse, such as ultrasonic humidifiers, or ionizing air purifiers with special chambers for your aromatherapy oils, so it's best to be careful.

mahrain 1y ago
Could accumulate in an isolated room, but following normal building ventilation standards, really shouldn't be an issue as shown by Brenner in 2023: https://pubmed.ncbi.nlm.nih.gov/38037431/ https://pubmed.ncbi.nlm.nih.gov/38037431/
- harvie 1y ago
  article specificaly mentions rooms with poor ventilation. if you have proper ventilation, then you don't need this system in the first place, because you will get ouside air UV sterilised by the sun...
scns 1y ago
> things that make our problems worse, such as ultrasonic humidifiers, or ionizing air purifiers What is bad about these?
- vintermann 1y ago
  Ultrasonic humidifiers require ridiculously clean water. Even regular distilled water is scarcely clean enough. You need to clean the water tank ridiculously well, ridiculously often. No one actually uses an ultrasonic humidifier like it's "supposed" to be used. When the water isn't industrially clean, everything dissolved in it is turned very efficiently into tiny particles. You'll get a fine white mineral dust everywhere. Ionizing air purifiers make ozone and the makers claim either that it's a good thing or that it's too little to worry about. The first is wrong, the second is a bad sell because the thing it's supposed to be removing is also (by itself) not a big health risk on any single day; the health benefit from removing particles is likely eaten up by the negative health effects of the ozone. You can clean air without ionization, so why? As far as I can tell, it's a pure marketing gimmick, the need to seem high-tech outweighs the actual utility of the thing. (That's also probably why ultrasonic humidifiers are popular, you can see the fog)

ur-whale 1y ago

Wont micro-organisms quickly adapt and start producing UV resistant strains?

VMG 1y ago
There is a giant orb in the sky that emits UV and has for billions of years. I think the microbes are still trying to figure this one out.
- mahrain 1y ago
  You are correct, however most of the harmful rays get filtered out in the upper atmosphere. Far-UV doesn't reach Earth, only UV-A and small amounts of UV-B (if the ozone layer is more or less intact that is!).
- Qem 1y ago
  > I think the microbes are still trying to figure this one out. They mostly figured it out a couple billion years ago. Cyanobacteria oxidized Earth's surface until the atmosphere was flooded with molecular oxigen, that gets turned to ozone in the stratosphere, filtering most UV. Pretty large engineering feat for a bunch of microbes.
mahrain 1y ago
The germicidal effect is a function of the DNA being directly affected by the UV rays and breaking apart. Very few organisms exist that could adapt, this would require external shells, skin etc, not typically found in microorganisms.
- jiehong 1y ago
  Tardigrades and organisms ables to survive space by having more efficient DNA repair mechanisms. Unlikely for most organism, true
ljsprague 1y ago
I also wonder about stuff like this. I think some things are just a bridge-too-far for organisms to evolve protections against. For instance, are we worried about using too much bleach? Or stepping on cockroaches?

mriet 1y ago

Idiotic and massively overlooks/underestimates how complex biology is. What about beneficial and neutral but important bacteria and viruses? "Air" is actually a complex soup of all types of things. This like applying HCl to a skin infection.

pjc50 1y ago
> What about beneficial and neutral but important bacteria and viruses? Such as what? There are some located in the gut, but pretty much everything else out there is in conflict with our immune system.
- pazimzadeh 1y ago
  where are you getting this info? almost every mucosal surface has commensal bacteria which can provide colonization resistance by other bacteria. lungs, skin, vagina, etc..
mahrain 1y ago
Studying a building's microbiome is really a new field. What happens to people if offices become boxes of sterile air and -surfaces? We don't know.
Llamamoe 1y ago
I would consider it unlikely that airborne germs form a significant input to our microbiomes. For example, the gut microbiome is in flux for about the first 3 years of life, and thereafter it's mostly only the relative abundances of different microbes that shift in response to diet, you need something like antibiotics or severe diarrhea to actually induce permanent changes (usually for the worse). Compared to that, there really aren't many microbes in the air. For children, it could very possibly be bad, but even then I'd expect most of their microbial input to come from their parents, food, and surfaces. Which are already grossly deficient compared to old-school rural settings, but I'm not sure if germicidal UV would make it worse.
bondarchuk 1y ago
I doubt it would be a problem for the microbiome [1] but I would worry about the immune system. Would being inside in sterilized air all the time mean you can't go outside or into a forest without getting really sick? [1] but who am I, it would still be worthwhile to check obviously

eythian 1y ago

It's a minor point, but it's interesting that they used having AC as a proxy for mechanical ventilation and conclude that it's rare in Europe. At least where I live (NL), mechanical ventilation is common - I think required in some situations - even though AC isn't. It's basically a fancy extractor fan that pumps air outside, so bringing fresh air in. That said, you'd need to reverse that flow to add filters.

lm28469 1y ago
Yes, few people have AC but almost everyone living in a semi recent place has mechanical ventilation in, at the very least, kitchen and bathroom, which thanks to physics renew the air of the entire falt/house.

owenversteeg 1y ago

Interesting, but I use a much more powerful germicidal UV source. Because of the power requirements it uses a fusion energy source located ~150M km away. (sunlight in fresh air.) In fairness to the article, ventilation was mentioned, but also quickly dismissed. The 60% efficiency figure quoted for ERV is also a bit on the low side for many contexts. And sure, ERV fans themselves use some power (say 50W) but that's about what you'd use in a decent size room with some UV lamps and a fan.

andrewrn 1y ago

I worked on a 254nm UVC fungicide system at an agricultural robotics startup. For some fungal pests like powdery mildew, there’s growing evidence that irradiating the crops at night (when the fungus has its UV defenses down), can effectively manage fungus outbreaks and save crops yields. This was specifically strawberries. I had to do a bunch of safety research and testing. We had some grower partners experimenting with it too and they had their workers operate the system without any coverings and everyone got sunburn. Unbelievable. Another startup working on this right now is TRIC robotics.