222-nanometre lamps kill pathogens and still sell a few hundred a year; the bottleneck isn't the technology
Far UVC uses 222-nanometre light to inactivate pathogens in the air while leaving the outer layer of human tissue unharmed; a South African TB trial is already seeing 90% suppression, yet the whole world buys only a few hundred units a year. The real bottleneck is how far the knowledge has spread.
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The argument · timestamps estimated from transcript position
222 nanometres is safe for humans because of a layer of dead skin
Far UVC in the 200-235 nanometre band, and 222 nanometres in particular, is absorbed by the DNA, RNA and essentially every protein in a pathogen, inactivating pathogens in the air at a rate equivalent to an extra 30-50 air changes per hour. The reason it is safe for people is mostly mechanical: human epidermis carries a layer of dead skin cells roughly 20 microns thick, packed with protein, which absorbs almost all of the far UVC. Conventional UVC at 254/265 nanometres lacks that strong protein absorption, which is why exposure to it is not advisable. The eyes are protected by structures like the eyelids and lashes; they tolerate a lower dose than skin does, but the risk of long-term damage is very low.
— VivianThe corner-mounted lamp is an existence proof, not the final form factor
Today's products are mostly mounted in a corner, because the beam angle is narrow and firing diagonally across the room maximises path length and average dose. The emitter puts out only about 100 milliwatts, and by the far side of the room the intensity has fallen close to zero; but the dose needed to kill pathogens is very small. Misha calls the current lamp an existence proof: there is no insurmountable obstacle, technical or logistical, an ordinary person can buy one and install it, and in the future this becomes an ordinary ceiling fixture. The real obstacle is not cost or regulation but that too few people know this exists.
— MishaElementary schools would gain most; workplaces will install it first
Vivian thinks the biggest benefit is probably in elementary and middle schools: ventilation is usually poor and children's immune systems are not yet mature. But parents hold safety to a high standard, so schools end up conservative, and workplaces, long-term care facilities and hospital waiting rooms will move first. The economics: one lamp covers about 250 square feet, an ordinary classroom needs 2-3, a university needs several hundred; a small building costs four to five figures for the whole thing, a large building runs into six figures; professional installation costs roughly as much as the lamp itself. Patrick adds that waiting rooms have high turnover, so any single person's accumulated dose is low while total occupancy time is very high.
— VivianTB resists UV the most, and its transmission is already down ninety percent
Preliminary results from the South African TB ward trial already show 90% suppression of transmission: the guinea pigs were exposed to the patients only through the air. Tuberculosis is not especially sensitive to far UVC, with roughly 10 times the resistance of influenza and coronaviruses, so the effect on common respiratory viruses may well be better. TB hotspots and nursing homes will be among the earliest sources of strong evidence. Vivian says pandemic prevention is the most exciting case: the more transmissible the pathogen, the more leverage an environmental intervention has. Old-style UVC once successfully controlled measles at an R0 of about 20, so pushing R from slightly above 1 to slightly below 1 is enough to avert a pandemic.
— VivianWritten into building codes, UVC becomes the cheapest path to compliance
ASHRAE 241 is currently the only infection-prevention standard, but it has not been widely adopted by any authority having jurisdiction; once it makes it into building codes, UVC becomes the cheapest way to comply, and it enters the existing building stock on the ten-year renovation cycle. The alternatives all fall short: upgrading the HVAC of an existing building is often impossible or extremely expensive; portable filters work (MERV 13 is enough), but pathogens are only one of the airborne contaminants, so filtration has to be paired with UVC. In high-density large spaces like auditoriums and gymnasiums, hitting a clean-air standard through ventilation alone is basically not cost-feasible; it has to come from UVC.
— VivianLamp prices can fall like LEDs, but price is not what decides installation
The best emitter available today comes from a single Japanese company running a high-margin business model; even stripping out all the profit, an emitter costs 15-20 dollars to make, and manufacturing requires hydrofluoric acid gas, which makes it harder to scale than LEDs. The end market is still small, with some sellers pricing lamps at 2000 or even 3500 dollars; AeroLamp prices at 500 dollars and aims to reach roughly 100 dollars within a year or two, with no technical innovation required. Patrick's read is that going from a few hundred lamps a year to a market in the hundreds of millions, unit prices will fall as fast as LED prices did. Misha's caution: falling prices do not automatically change willingness to deploy. Information is the bottleneck.
— MishaWhether it pays off at home depends on whether disease spreads at close range
Misha thinks an ordinary household does not have much transmission in it, so 500 dollars does not pencil out and 100 dollars is where it starts to make sense. Vivian pushes back: she has just had a baby, and the two lamps in her home run during gatherings and when guests come over. A fever in an infant means the emergency room, possibly admission, possibly a lumbar puncture, so preventing a few illnesses pays for the lamp. Behind that disagreement sits the biggest failure mode: if most common illnesses spread mainly through short-range, high-dose transmission within two feet, an environmental intervention can only do so much, reducing the severity of infection rather than preventing it. Even then, lowering the viral dose may still make the illness milder.
The first dollar should buy global awareness, not more lamps
Misha says the first money to spend is on building global awareness: the whole world may buy only a few hundred lamps a year, and almost nobody has heard of 222 nanometres. Vivian leans toward formal trial deployments, arguing that too much hype could trigger a backlash and that expansion has to be done responsibly; Paris Hilton would be a better spokesperson than Taylor Swift. The commercial shortcut does not require convincing the public: companies have already internalised the cost of employee sick days and caregiving absences, firms like Google have people whose job is employee health, and once the arithmetic is clear they will install. Building owners decide unilaterally, which also routes around the spoiler's veto.
— MishaIn their own words · checked verbatim
So on a chemical, biological level, the special thing about far UVC is it is absorbed by the DNA and RNA of pathogens, as well as by essentially all proteins. And this is very important, because the fact that it's so heavily absorbed by proteins is a thing that makes it much safer than other germicidal UV wavelengths.
Vivian0:58
Essentially, it's not good for living cells to be exposed to UVC of any wavelength. But the difference is that humans have a 20-micron-thick layer of dead skin cells that are chock-full of proteins that essentially absorb all far UVC.
Vivian3:25
One of the big benefits of it being more effective than sunlight as a disinfectant is that you can actually use it at pretty low power levels. So the emitters we're using, they're putting out like 100 milliwatts, right? Which is really not a lot.
Misha9:24
So there's going to be some critical coverage point within a community where the suppression really takes off. And we have modeling on this, but yeah, I think it's really, really uncertain.
Vivian21:48
And also I should point out that we have some really encouraging results on tuberculosis specifically. There's a trial going on in South Africa that already has preliminary results, and they're seeing 90% transmission suppression in these TB wards.
Vivian23:24
No, I definitely think that's a huge benefit. I also think because it's part of the built environment, you need a lot fewer people to be involved in the prevention process, right?
Misha32:49
And if a certain amount of infection prevention gets written into building codes, and then these are broadly adopted in whatever the authority having jurisdiction is — that might be on the state level or on the county level — this means that these interventions just get built into buildings on a ten-year renovation cycle.
Vivian34:23
So I would much rather my kid catch whatever it is that's going around at ten than at five, and I'd rather it happen at five than at one. But I'd really rather it just not happen. There's just no benefit.
Vivian56:09
Figures
| Thickness of the dead-skin-cell layer in human epidermis | about 20 microns | 3:25 |
| AeroLamp emitter output power | about 100 milliwatts | 9:24 |
| Coverage per lamp | about 250 square feet | 17:31 |
| Lamp price and installation cost | about 500 dollars per lamp, with installation costing roughly as much as the lamp | 17:31 |
| South African TB trial result | 90% suppression of transmission | 23:24 |
| Relative resistance of TB | roughly 10 times that of influenza and coronaviruses | 23:24 |
| Measles R0 | about 20 | 27:16 |
| Estimated global annual sales | possibly only a few hundred lamps a year | 39:11 |
| AeroLamp target price | about 100 dollars per lamp | 45:14 |
Glossary
- far UVC
- Ultraviolet light in the 200-235 nanometre band, mainly used at 222 nanometres; absorbed by protein, so it kills pathogens while remaining safe for the outer layer of human tissue.
- krypton chloride excimer lamp
- The main far UVC emitter today; its manufacturing process is more complex than an LED's and requires hydrofluoric acid gas.
- ASHRAE 241
- The indoor infection-prevention standard set by the American Society of Heating, Refrigerating and Air-Conditioning Engineers; not yet widely written into building codes.
- R0
- The average number of people one infected person infects; above 1 it spreads exponentially, below 1 it dies out on its own.
- hygiene hypothesis
- The claim that excessive cleanliness causes allergies and asthma; the modern version holds that immune training comes from environmental bacteria and does not require actually getting sick.
How to listen
Founders working on respiratory disease prevention, people in construction and HVAC, hospital operations staff, and parents who want their kids' schools to upgrade the air.
Skip the opening introductions and the two mid-roll ads; the body starts at 00:58 and there is no filler in it.