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.
Is there any reason why they can't just be installed inside air purifiers/ventilation?
Especially since you could probably get more mileage out of the same amount of light energy by forcing the air through a narrower passage, since only airborne particles are actually going to absorb any energy anyway, and air is mostly just empty air.
Yeah I saw a lamp for this and it had a proximity sensor to prevent overexposure. There's no way I'm buying a lamp that needs that to be safe. Especially if it's expensive and only lasts a year or two.
there are much simpler and more reliable ways to significantly reduce indoor air contaminents.
one is a building method that produces a "floating" slab floor, that has a small gap around most of the walls, and the underfloor space is vented upwards with a chimney, this creates a small but continious air current that removes most dust and other things in the air.
And then the simple expedient of useing radiant heat sources, that while not as lethal as UV, are
in fact quite deadly to bacteria and anything tiny with a high water content, but completly harmless to humans and ,animals,plants. Couple this with hard, smooth ,surfaces that are designed so that there no crevices or areas filth can acumulate, useing hard woods,glass,tile,metal,leather/vinyl l,high gloss paint,for surfaces. No cloth, no carpet.While not exactly cosy or friendly, it makes getting home that much nicer.
Cheap, reliable, low maintenence, implimentable at scale, now.
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.
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/
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.
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).
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.
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.
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.
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.
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.
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?
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.
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.
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
I recently read the book "Invisible Friends," and in it, among other things, the author does go on to explain that it's theorised that many skin infections come from a lack of biodiversity in a persons' skin microbiome, because the "good" or neutral microbes compete with the "bad" for resources. Supposedly people who share a house together often have similar gut microbiomes, too.
So yeah, I don't know. I think you have a point here.
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.
mahrain|5 months ago
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.
Llamamoe|5 months ago
Especially since you could probably get more mileage out of the same amount of light energy by forcing the air through a narrower passage, since only airborne particles are actually going to absorb any energy anyway, and air is mostly just empty air.
modeless|5 months ago
unsnap_biceps|5 months ago
metalman|5 months ago
And then the simple expedient of useing radiant heat sources, that while not as lethal as UV, are in fact quite deadly to bacteria and anything tiny with a high water content, but completly harmless to humans and ,animals,plants. Couple this with hard, smooth ,surfaces that are designed so that there no crevices or areas filth can acumulate, useing hard woods,glass,tile,metal,leather/vinyl l,high gloss paint,for surfaces. No cloth, no carpet.While not exactly cosy or friendly, it makes getting home that much nicer. Cheap, reliable, low maintenence, implimentable at scale, now.
vintermann|5 months ago
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|5 months ago
scns|5 months ago
What is bad about these?
toast0|5 months ago
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|5 months ago
andrewrn|5 months ago
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.
Animats|5 months ago
[1] https://cybernightmarket.com/products/mini-far-uvc-lights-se...
mahrain|5 months ago
eythian|5 months ago
lm28469|5 months ago
ur-whale|5 months ago
unsupp0rted|5 months ago
mahrain|5 months ago
ljsprague|5 months ago
VMG|5 months ago
I think the microbes are still trying to figure this one out.
wiseowise|5 months ago
mriet|5 months ago
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.
Llamamoe|5 months ago
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|5 months ago
[1] but who am I, it would still be worthwhile to check obviously
pjc50|5 months ago
Such as what? There are some located in the gut, but pretty much everything else out there is in conflict with our immune system.
mahrain|5 months ago
Lapra|5 months ago
So yeah, I don't know. I think you have a point here.
more_corn|5 months ago
wpm|5 months ago
pazimzadeh|5 months ago
a moderate amount of UV stimulates vitamin D production, suppresses inflammation, and turns on DNA repair pathways
nikolay|5 months ago
[0]: https://www.nature.com/articles/s41598-020-67211-2
Retz4o4|5 months ago
owenversteeg|5 months ago
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.