让杀菌光照进来：这款500美元灯具或可阻止下一场大流行病——来自《Complex Systems》

Hi-de-ho, everyone. My name is Patrick McKenzie, better known as Patio11 on the internet. As longtime listeners of Complex Systems will know, I think that Far UVC is one of the sleeper picks for among the most important technologies being developed today. Far UVC is a wavelength of light that can deactivate viruses and other pathogens, and it is possible that we will be able to introduce this into our built environment, into our homes and offices, via specially made lamps for infection control.

I'm honored to be joined today by Misha, who is the CEO of AeroLamp, and Vivian Belenky, who is the chief scientist of AeroLamp and also a researcher at Columbia University. Thanks very much for coming on the program, guys.

Yeah. Good to meet you.

Good to meet you as well. So, for folks who haven't heard the Far UVC gospel yet, can we talk briefly about what this wavelength of light actually does, both on the chemistry and biology level and hopefully on the social and technology level?

1. Far UVC Targets Pathogens Safely

On a chemical and biological level, the special thing about Far UVC is that it is absorbed by the DNA and RNA of pathogens, as well as by essentially all proteins. This is very important because the fact that it's so heavily absorbed by proteins is what makes it much safer than other germicidal UV wavelengths.

Essentially, a pathogen or any microorganism—anything without significant protections like humans and animals—is going to be inactivated. It's still in the air, but it can no longer replicate, and this works extremely fast. It's essentially like having an extremely strong air purifier running in a space, except instead of maybe giving you an extra air change or 2 in your space, you can get the equivalent of 30 to 50.

And this is just a wavelength of light that happens to be invisible. It's something that we get in sunlight already, presumably, right?

No, actually. Sunlight is primarily UVA and UVB. UVB in particular is what we're most worried about when we're concerned about the risk of skin cancer and cataracts.

UVC is actually completely blocked by the ozone layer. This makes sense because UVC is quite efficient at inactivating microbial life. Probably the surface of our planet would look very different if it were present here on Earth.

There is no UVC in sunlight. Sunlight is germicidal, just like UVC, but to a much lesser extent. While sunlight does kill germs, it does so because there's just so much more sunlight than there is ever from any UVC lamp. Even though sunlight is only mildly germicidal per photon, it can still do the job.

The legal beagle in me has to say that Oliver Wendell Holmes was empirically disproven by the science. Sunlight is, in fact, not the best disinfectant.

This is an interesting wavelength of light. I personally have done a little bit of the reading and am relatively well-informed about the safety story, but I think that the typical member of the audience probably isn't. What is the chemical and biological reason that this is safe for us?

You've mentioned that it gets blocked by basically any proteins, so proteins in our skin and epidermal layer, presumably. But how is it safe to, for example, look at?

This is actually much more of a mechanical story than a chemical or biological story.

Okay.

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.

I should say this is unique to Far UVC—the wavelengths from 200 to 235 nanometers, principally 222 nanometers, which is what is most commercially viable right now. Longer UVC wavelengths, at 254 nanometers and 265 nanometers, which are used in water disinfection, do not have such significant protein absorption.

I'm not going to say they'll give you cancer. Relative to UVB, they're thought to be less carcinogenic, but they are not pleasant to be exposed to. So it's really something that is unique to the shorter wavelengths in Far UVC.

This high protein absorbance is due to the stratum corneum, the outer layer of the skin. It absorbs almost everything, and what is not absorbed is absorbed in only the very upper layers of the skin. Those skin layers generally slough off and become part of the stratum corneum within typically a couple of days.

I've never seen a study that showed any significant biological activity down at the basal skin cell layer, where you would start to worry about cancer if there were any damage to the DNA there.

Now, the story with the eyes is a little bit more complicated, and this is because there isn't a convenient dead skin cell layer—or dead eye cell layer, whatever that might mean—to protect us. But eyes are protected in the same way that they are protected from sunlight. We have eyelids, eyelashes, eyebrows, and a brow ridge. All of these things reduce the effective dose to the eye.

This does mean that, despite these mechanical protections, the eye is more vulnerable. There is the tear layer, which has some lipids and proteins, and that absorbs some of the Far UVC, but actually only about 15%. The rest of the incident dose would be absorbed in the epithelium, so a relatively lower dose might produce eye pain or discomfort.

The positive story there, though, is that even though these are living cells, they're still full of proteins, and the absorption is thought to essentially totally stop after the first few cell layers. So any chance of long-term damage is, in my opinion, fairly low, although this technology hasn't been around for long enough to do extremely long-running studies.

There have been a few long-run eye-safety studies. Actually, there's 1 1-year study and 1 3-year study going on, I think, in Japan. But it does mean that the safe, effective eye dose is lower than the safe, effective skin dose. We're still figuring out exactly what that is and exactly how to translate that into industry practice.

We are generally pretty conservative. But the good news is that it’s sort of like looking into a bright light, and not like looking into an infrared laser: if you feel any pain, that means you flinch away, and then you’re not really worrying about long-term damage. This is very different from, say, infrared lasers, where you could get a blinding dose and feel nothing. So thankfully, it’s nothing at all like that.

Yeah. If anyone has ever been in a lab that has lasers, the safety briefings are, first, terrifying, and second, if you feel anything, it’s far too late.

Yes. With far-UVC, if you feel something, stop looking at it. To clarify, it’s not that you might be sitting in the room and suddenly your eye starts hurting. It’s more like: did you accidentally climb up and stare right into it for a couple of minutes without turning it off? We’re talking more about accidents of that nature.

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. The emitters we’re using are putting out around 100 milliwatts, which is really not a lot. Over the distance of a room, it basically decreases to around 0, especially if you’re farther and farther away, right?

Yes. You need very little dose of this stuff to get a pretty rapid germicidal effect.

So we’re starting to see these emitters in the corners of rooms in more, let’s say, tech-forward places in the San Francisco Bay Area. I see your branded emitters more than most. Can you describe what the typical deployment of this would look like?

2. Building The First Installations

For now, we’re doing these corner-mounted units, mostly because it’s a little more cost-effective to mount them in the corner. This is because these lamps have a fairly narrow beam angle, which means that, to maximize the average dose in the room, you want to maximize the path length of that beam. Usually, that means mounting it in a corner and pointing it toward the opposite corner, which gets you a larger average dose over the space.

In the future, I think ultimately we’re looking at normal overhead ceiling lights: just a boring ceiling fixture, like a smoke alarm or any number of random pieces of building infrastructure in drop ceilings in offices, hospitals, and schools. We’re doing it this way right now because it’s a little easier to install. We wanted to emphasize that this is something you could just buy for your space and get on with it. Misha can talk a little more about that.

I basically see our current lamps we’re sending out as a very important existence proof that the technology is fundamentally ready to go. There aren’t any insurmountable technical difficulties, and there aren’t any insurmountable logistical difficulties to deploying it. There are still many difficulties, as there are in running any business, particularly any business that involves high-tech components.

But it’s not something where you can only get this for $10,000, or you can only get this if you’re a secret government lab. This is something that’s pretty much ready to be deployed.

One of the things that I like about this is that, as you mentioned, the tech is basically proven. We’ve done extensive lab studies about this, et cetera, et cetera. It is something that, bluntly, fits on a shipping container from China.

One of my theories about the world is that everything that fits on a shipping container from—without loss of generality—China craters in price over time, particularly as you scale up production a bit. While many of our other medically oriented interventions are consistently high-priced due to Baumol’s cost disease and other reasons, this is something that we should eventually be able to buy for not much more than the price of lighting. There are very few people or institutions that go, “Darn, we’re building out a hospital, but we just can’t afford the lights in it.”

So it’s largely a matter of will, I think, for deploying it, although you’ve probably had this conversation many more times than I have. Why does it not exist already in all of the hospitals?

Can you talk about what the research suggests with respect to this? As we’re prioritizing the rollout, where should we prioritize?

3. Choosing The Best Early Sites

Right. So this is a tough one. If I had to say where I think there would be the most benefit, I would say elementary schools, maybe middle schools, because they are often extremely poorly ventilated, and children are immunologically naive. One issue with doing airborne disease-transmission studies is that you’re using healthy adult volunteers.

It turns out that healthy adults generally don’t get the flu. You need a lot of shots on goal to successfully catch the flu. Children are a different story. It is a bit trickier, though, in that I am convinced on the strength of the safety evidence.

I don't know that we have a large enough pile of safety evidence that a large enough fraction of parents of children would be thrilled to try this relatively new technology in schools. I do expect schools to be relatively conservative, perhaps with the early rollouts happening in private or specialty schools. So I think ultimately occupational settings of some sort are going to see it earlier, even though I don't necessarily think that's where the very largest benefit is.

I think long-term care centers and hospital waiting rooms are big ones where the benefit is high, so any concern about photobiological risk is going to be more acceptable.

Presumptively, places that have a relatively transient population. So in a hospital bedroom, you might have a patient there for a relatively long time. But presumptively, people do not spend multiple days in the hospital waiting room. And so if you have some worry that there's some dose level that would be potentially inimical to a person, they are less likely to get that dose level in the waiting room than they are in other spaces.

Conversely, when you're not counting an individual human's dwell time in a space, the aggregate amount of dwell time in the waiting room is quite substantial. It's just spread over hundreds of patients. So I do think that it is likely to happen in private schools, maybe faster than public schools. And one reason is that, when I do the back-of-the-envelope numbers for it, it's something that a single parent could probably fund just by deciding to do it if they get the school on board.

Indeed, a few of my tech friends have discussed potentially doing that for the schools their children attend. Misha, can you talk a little bit about the economics of this, on a per-room and per-institution basis?

Yeah. So we usually say something like 250 square feet per lamp is how much coverage you would get. So for a standard classroom—this is sort of... I guess a standard classroom is a tough question because there are the standard classrooms as they actually exist, and then if you look into, say, California guidelines for a standard classroom, they're actually much bigger than standard classrooms tend to be. But that would be 2 to 3 lamps per classroom, maybe 4 for a bigger one.

And so for a lot of schools, you're looking at a lot of lamps, right? Dozens. For a really big institution, like a university, you're probably looking at hundreds of lamps. Universities are kind of a front-runner because, again, it's not children; it's older students, so it's a little easier to get installations set up.

One of our competitors recently set up a big installation in a Florida university. I haven't heard any details yet, but they're apparently collecting a lot of good data that way. This is the kind of thing where, on most small buildings, you're looking to spend maybe 4 to 5 figures if you want to outfit the whole building. And then once you're getting bigger, you're looking to spend maybe 6 figures purely on lamps, and then installation also.

Usually we say installation will cost you probably about what the lamps will cost you if you're hiring professionals to do it. If you're just doing it yourself, installation is basically free, right? It takes 10 minutes to stick one on the wall and plug it into an outlet. But if you're doing permanent installations, you're going to want to run wiring through the ceiling, that kind of thing, right?

Yeah. So the budget is as much for the installation as for the lamp itself. That's kind of just a rule of thumb, on average across all possible electrical systems and ceiling types. Even if this were happening on a mass level and we were hiring professionals to do all of it, I think for many typical scenarios it could be quite a bit cheaper. But just on average, when we're talking about mass-scale modeling, I think roughly double the cost for installation is a reasonable, conservative estimate.

And so at the moment, it's something like $500 a lamp. So if you need 2 of them for a room, that's $1,000, and then $1,000 for installation, and then multiply by the number of rooms that are at the top of your priority list. It's useful to point out that this is something electricians are very qualified to do already. You just say, “Hey, there is a weird light fixture that goes in the corner,” and they say, “Okay, I have done light fixtures before. That isn't an unsolved problem in materials science.”

One of the reasons that UV has not really been adopted more generally, even though it's been a known technology since the 1940s and 1950s, is that older wavelengths are more dangerous, so they have to be installed a lot more carefully. You can install UV in the upper part of a room where it's safe for people, but if they mess up an upper-room installation, then people are getting eye damage very quickly.

Whereas you can't really mess up a 222-nm installation that badly because it's innately a lot safer. And so the level of expertise is, like you said, any electrician can do it instead of needing an expert UV installer.

I'm familiar with standard lamps, although they changed a little bit in the LED era, where you have to go and replace the bulb every once in a while. What's the average lifetime of these installations?

Yeah, we think that the bulbs that we're using right now—the manufacturer will admit they'll last at least 10,000 hours while maintaining 70% output. I've seen some data that suggests it's actually a bit longer than that, maybe more like 13,000 to 14,000 hours.

If you are only using it in an occupational setting for 8 hours a day during your workweek, that's about 5 or 6 years of usage before you need to do any replacements. And if you're running them 24/7, which I don't know what scenario that would be most desirable in, that would be just about a year and a half.

I could imagine maybe a transportation scenario where you had them in, for example, a train station or an airport, where they would want to run them 24/7 or something pretty close to it. And I guess the big $64,000 question—or more now that a dollar is worth less than it used to be—is when will we start seeing the actual results in the physical universe?

When does the data start getting sort of undeniable? That's like, if you install this, then you win in terms of the amount of sick days you have and the clinical consequences.

4. Proving The Health Benefits

Yeah. So I think this is a really, really tough question. There are a number of reasons that these sorts of randomized controlled trials for an environmental disease-transmission intervention are quite hard to do. We're not entirely sure that we know how to design such a trial, but in principle, you should expect that this will roughly follow a sigmoidal shape.

The first few adopters are going to see sublinear benefits because maybe you install it in your office and nobody gives each other the flu in your office, but then your kid's school doesn't install anything and the flu goes around there, and then you just catch the flu from your kid. 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 I think it's really, really uncertain.

I think I'm actually a lot more optimistic than that. I think a lot of specialized use cases are going to see fairly strong evidence, a lot faster and a lot more easily—basically, situations where people are not as social, not as mixed, or pathogens that are particularly susceptible. So there have been really good results on tuberculosis, for example.

This is not really something we think about day to day in America, but there are a lot of institutions and places that are tuberculosis hotspots that are also not doing a ton of social mixing. This is a big problem in a lot of countries that are not America. But even in America, there are places that have a lot of tuberculosis. And I think those places will see pretty noticeable drops in transmission fairly fast and pretty reliably.

I think that kind of thing will be forthcoming relatively quickly compared to if you put this in a school, in a community. We don't really know that fast. I also think long-term care centers and basically senior centers are another place where we're probably going to see results relatively faster because there's just not as much social mixing there with the rest of society.

I would agree with that. 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. This is an animal study, so the way it's set up is that there are guinea pigs that are exposed to the humans only through the air, and they're monitoring what percentage of the guinea pigs get tuberculosis.

But tuberculosis is actually not very sensitive to Far-UVC at all. It’s relatively resistant. I would say it’s about maybe 10 times more resistant than your typical respiratory virus, like flu or coronavirus. So are flu and coronavirus transmitted through the air in the exact same way as tuberculosis? No, probably not.

But there is, in fact, a lot of reason to be optimistic. I think Misha’s totally right about long-term care centers probably seeing much more immediate benefits than the school or office case, or perhaps boarding schools. I think boarding schools could be a relatively more immediate example.

I think this is going to be interesting because there are some institutions that require a stack of academic papers on this with confidence intervals, et cetera, et cetera. But when you’re talking about 90% decreases in infections, for example, the anecdotal evidence will pile up in certain communities extremely quickly.

It is just nakedly and obviously incentive-compatible for a case like a long-term care center. Regardless of who owns it, a PE firm or otherwise, they would strongly prefer that the residents not die. That is both the humanitarian mission for them, plus they get paid based on how many residents are still living at the moment.

You could imagine it having a high viral coefficient in that community of practice as soon as a chain installs it in one location and is able to check at the end of the month: “Well, we had 34 infections in the median of our locations, and in the one where we installed this, we had 3.” Then they could make the obvious decision very quickly after that.

Knock on wood, I hope that we will see evidence of the obvious decision getting made all over the place on a timeframe of months to a small number of years from now, followed by the broader societal rollout that this will likely take.

5. Preventing Future Pandemics

So we’ve talked about the decreasing-infections-locally case, but I think the huge societal upside here might be decreasing the total load of infections and, in particular, kneecapping future pandemics before they start. Can you talk about some of the pandemic math that we were unfortunately all forced to become experts on back in 2020, and what this does to the potential factors of virality and similar?

Yeah. I think the pandemic-prevention case is by far the most exciting element here. When you’re trying to market something to ordinary people in non-pandemic times, and when I talk to people about this, I really avoid mentioning the pandemic because people do not want to hear it. I think we’re all collectively traumatized, and we just don’t want to talk about it. So we’re talking about preventing colds and flus.

My honest assessment is that I’m much more uncertain about our ability to prevent the average cold, which is just not very contagious. Probably, if you’re getting someone’s cold, it’s because you spent an extended period of time interacting with them quite close. Can we prevent some colds in immunocompromised people and in some situations? Yeah, I think so.

But I’m actually much more confident that we could kneecap a future respiratory pandemic like COVID-19 or worse, just because, paradoxically, the more contagious something is, the more surface area there is to keep it from getting as bad as it could get. In fact, one of the earlier use cases for traditional germicidal UVC, which uses a different, more dangerous wavelength—the 254-nanometer wavelength—was to control measles.

Measles is just absurdly contagious. It is probably the extreme of how contagious a pathogen can even be. I think it has a reproduction number of 20, so each person who has it will, on average, infect 20 others. I believe that COVID-19 at its worst had a reproduction number of one point something. So UVC was able to successfully control measles outbreaks.

I think that makes me really optimistic that a relatively low level of coverage in key areas—transport hubs, for example, and other gathering places where people who aren’t actually in communities together are mixing—is where we can do pandemic suppression for relatively low cost.

No, I definitely think that’s a huge benefit. I also think that because it’s part of the built environment, you need a lot fewer people to be involved in the prevention process, right?

This is one of the big problems with COVID: vaccination requires a lot of people to opt into vaccination, and masking requires a lot of people to opt into masking. If you have whoever owns a building decide unilaterally, sometimes it’s just one person, and sometimes it’s a board of directors or something. But that takes way fewer people to reduce infections in an area than previous prevention methods, right?

Yeah. And if a certain amount of infection prevention gets written into building codes, and then these are broadly adopted by whatever the authority having jurisdiction is—that might be at the state level or the county level—these interventions just get built into buildings on a 10-year renovation cycle.

I think there is some potential here in going through building codes, because right now we only have one infection-prevention standard: ASHRAE 241. It’s an amazing standard that was put together very quickly, but it’s still under construction, and it’s not yet broadly adopted by any authorities having jurisdiction.

But if the standard says you need this much infection prevention in your building to be compliant, and UVC is the cheapest, easiest way to do that, people are going to do that. I do think that one really, really major advantage—maybe the advantage—of Far-UVC and UVC generally is that it is such a cost-effective way to get the required amount of infection prevention into an air-treatment space.

The sort of competing technologies—they’re not quite competing. Presumably, this is something that you could deploy in parallel, but your other options might include a huge upgrade to the HVAC system to cause more changes in the actual physical air in the room per hour, which requires upgrading both the central HVAC and also presumably all the vents, et cetera, and might be either impossible or extremely cost-ineffective for buildings that already physically exist.

Whereas this is, again, just: plop the light in the corner, and then you’re done.

Another comparison technology might be portable air filters, actually—not necessarily HEPA, but a lower rating can actually be just as effective and much quieter. So, just a MERV 13 portable air filter.

I do think these things are additive. We should absolutely be upgrading ventilation. We should be getting more outdoor air and more recirculated, filtered air. We should be using—you can call them portable filters, but you can also install them in the room. We can broadly call these in-room air cleaners.

I think these are some of the most cost-effective options. And for filter-based in-room air cleaners, you’re going to want them alongside UVC anyway, because pathogens are not the only airborne pollutant.

There's also chemical pollutants. There's particulate matter, dust, and allergens. Far-UVC actually does have a modest effect on allergens through the same protein-absorbance pathway, but it's much smaller than conventional filtration. So we should be doing all of these things.

But for pathogens specifically, just moving the air tends to be really, really insufficient, especially for very large spaces that are relatively densely occupied. In auditoriums, lecture halls, and gyms, it would be really, really difficult to meet the clean-air standard without UVC—essentially cost-prohibitive for most buildings.

This is one of a panoply of options we have with regard to infection control in our built spaces. I was about to say additive, but it's probably multiplicative, or better, if one actually does the math with regard to other non-pharmaceutical interventions—or pharmaceutical interventions, for that matter. If we have vaccines, they have some penetration rate in the community, et cetera, et cetera. The vaccine almost certainly doesn't become less effective just because there is less of the virus circulating around.

But given that this is easier to deploy and requires less coordination among people, there's also a political-economy question here that's dancing in the background. Hopefully, there will be less opposition to simply having light in the corner than to having needles deployed all over the place. It makes all of our existing and future technologies better to have this deployed alongside them.

Yeah, I think that's definitely true.

6. Breaking The Adoption Bottleneck

I once made a bet with someone that we would have broad deployment of this in the United States by 2030, and I think I'm going to lose that bet, unfortunately, because we're not moving at quite that speed. But if you were to put your finger to the wind, what does the curve look like for deployment of this over the next couple of years in maybe an optimistic scenario and then sort of a baseline scenario?

I think we're not exactly even on the curve. Worldwide, it might be as low as just a couple of hundred of these lamps sold per year. I don't even have a great sense for whether this is going up, but I think essentially it's a matter of, does this idea go viral? Har har. If it takes off and becomes, “Hey, this is a thing you can and should do,” then I think we can maybe look at the speed of deployment of LED lighting as a case.

We're still looking at at least a decade after it really takes off to get truly wide deployment. That 10-year renovation cycle for commercial buildings is going to play a role here. So it's really just a matter of when we get to that tipping point and how we get there.

This is something that really keeps me up at night because I talk to people, and people think there must be some good reason that this isn't getting going. There must be a regulatory barrier, a cost barrier, or a critical piece of safety research missing. Not that there isn't lots of safety research and other kinds of research still to do, but there's nothing supercritical where it's like, “Oh, we just need to know this and then we can get going.” There's not really any regulatory barrier either.

It's maybe just a social-diffusion question. Do we need a global awareness campaign? How do we get this out there? I've been in research for my entire career, so I'm not an expert in how to run a global awareness campaign or how to make one actually effective, and I certainly really wish I was.

Calling back to something that you said earlier, we're all somewhat traumatized by the pandemic, but implicitly we are racing the next pandemic. Hopefully, we have this up and running in as many spaces as possible prior to the somewhat inevitable crash efforts to again improve our physical spaces and other resilience that would be activated in the ordinary course during pandemic times. Ordinary course, to the extent that anything is ordinary during pandemic times.

It's a combination of frustrating and intellectually interesting that there is no barrier at the moment. It's a product that's commercially available. I guess we'll say a few words about scaling. This is presumptively manufactured in—without loss of generality—China. One thing we've learned from LEDs, among many other technologies, is that China and the industrial ecosystem there are very good at scaling up production of things for which there is a demand.

Is there any particular reason why this would be harder to scale than, for example, LEDs were?

There have been a few reasons, but they're not that major. The current manufacturing of the best emitters, which we think are the most cost-effective and have the best lifespan, is handled by only one company from Japan. They're generally in the business of making high-end, high-margin products. So even if we cut down all of their margin, we're still looking at a per-unit cost of $15 or $20 per emitter, which puts them in a different category than LEDs. They're not as easy to scale.

They require hydrogen fluoride gas as part of the manufacturing process. This is technically just a lot less simple than LEDs. It's still something that's very feasible to scale up. It's not something that's, on first principles, unscalable; it's just not as easy as LEDs.

I would push back that it's more complex than LEDs. The thing about LEDs is that it's extremely complex and capital-intensive to produce LED chips. But once you've made that capital investment, you can scale it very, very effectively. You put in tens of billions of dollars of capital, and if there's enough of a market, that makes sense to do.

Right now, these krypton chloride excimer lamps are on a different, less aggressive cost curve. I don't think they could get as cheap as the white LED. But there are hopes for some solid-state, chip-based solutions for far-UV emission. I just think that we're looking sufficiently far out that we're nowhere near the cost floor for even what we have here.

Once we're in this beautiful unicorn world where we're selling tens of millions of lamps and really rolling this out, how do we push the cost floor of a krypton chloride lamp even lower? How do we get solid-state, chip-based, scalable technologies online? I would love to have that problem. I would be so joyful if we had that problem.

Given that the cost doesn't seem to be the major barrier to deployment right now, and that, at least in the United States, you modeled 50% of the cost as labor, where that is very difficult to compress, I would assume that the cost drops as we scale production. That's generally how it goes in manufacturing.

But there isn't a radical step change in the likelihood of deployment or the ease of deployment as a function of reducing cost, it seems to me.

The existing industry is just so small, and as I said, it's kind of high-margin as a business model. So I think there is an—I don't know if I would call it a radical step change, but I think there's probably a pretty big inflection point at some point, because a lot of the lamps in this market are being sold for around $2,000. I recently heard someone sell their lamps for $3,500 each.

Once we're talking about installations where you need 100 for your building, that adds up really fast if you're spending $3,000 per lamp. So I do think that cost is probably a barrier in a lot of deployments.

But that cost is not fundamental to the industry. That cost is just an artifact of the fact that these are tiny companies that need to have high margins to survive. I think this is a very tractable thing if you're looking at it from the perspective of whether the world can throw money at this to get deployments a lot faster and cheaper. I think this is very feasible.

As we're talking about a total addressable market at the moment of hundreds of lamps per year transitioning to tens of millions or hundreds of millions, our priors should heavily be on the cost per unit going down pretty aggressively.

The cost per unit is really—I'm saying the cost per unit is not the cost, right? That's the price per unit.

I guess this was sort of our theory for offering a $500 lamp: that there is this inflection point. Our goal is to drop that even further.

I don't think there's any reason that in the near future, the next couple of years or so, or even sooner, the price couldn't be on the order of $100 per lamp. And that's with zero technological innovation of any sort.

And for the benefit of people who haven't seen your website, not to put too fine a point on it, this is a thing that you can literally go over to AeroLamp's website and buy right now. It comes in a box to your home or office, and then it is as easy to install as any other lighting fixture.

Actually, even easier. You just stick it on a tripod, put it on top of your bookshelf, or use a drywall anchor and stick it on your wall. Typical overhead lights can be quite a bit more annoying to install. I've done it in my home a couple of times.

And, full disclosure, I don't have it in my house yet, but I have considered it, and it exists in several commercial spaces I've been in in the San Francisco Bay Area, among others.

I get asked this question all the time: “Oh, should I get an AeroLamp?” But I think most private homes—the cost-benefit analysis is not really in favor of getting one, just because there's not that much disease transmission. Most people don't live in a big house with 20 people or anything, right? If it's you and your family, I don't think the benefits are going to be that high.

Although, obviously, this changes based on your own personal cost-benefit analysis, right? If you're particularly rich, particularly value not getting sick, or if you're immunocompromised, this sort of changes the balance. But for most people, having it in their home for $500 is not actually cost-effective. It doesn't actually price out very effectively. Maybe once they're down to $100, then yes.

I don't know. I would actually push back on that. I think there are quite a lot of families. I think the societal benefits are not particularly concentrated for individual homes. For individuals, in quite a lot of situations, it can be valuable.

For example, I had a baby 2 months ago, and babies essentially do not have immune systems. I quite valued having people over and around to help out postpartum, and I was using my lamps. I have 2 in my living room, and I turn them on when I have company. I turn them on when I host events and gatherings.

I think for individual homes, it's less something that you might have on all the time, but maybe something you like to have for home-health reasons. It's sort of like the ventilator in your kitchen. It is something that you quite like to have for home-health reasons. Maybe not at the $500 price point, though.

I think if you actually monetized the potential health benefits, it would look quite a bit better. Getting sick is very, very costly, so you don't need to prevent that many episodes of illness. Especially in tiny babies, where if a tiny baby gets a fever, you're looking at an emergency hospital trip, hospitalization, and potentially a spinal tap, and it's all deeply upsetting for everyone involved.

So I think you should rationally be extremely willing to pay to lower the probability of small babies and other immunocompromised people getting infections. But the societal benefits of homes are just kind of meh. That's not where I am most going to be pushing for this to go out. I think schools, transport hubs, and that sort of thing are where you'll see much broader social suppression.

When I was doing the back-of-the-envelope math—and I have not devoted the last couple of years to researching this—my thought was that the case for a home shaped like mine, where there are 4 occupants, 2 of whom are school-aged children, is not that great yet, except for the aesthetic benefit. Putting your chip on the table, this is something that I hope gets deployed widely in the future.

For special circumstances, sure. Also, given that most people who listen to Complex Systems are employed tech professionals or similar, the absolute number is probably not that big a barrier. But be that as it may, there is a question that we sometimes ask in investing, which I think is a clarifying one.

If it fails to work—if this doesn't achieve the societal-level benefits that we expect it to—why? What is the thing that we don't have confidence in, that we could potentially learn more about in the next couple of years in a way that would disappoint us negatively?

7. What Could Break The Thesis

For my part, it would be that it turns out that a huge chunk of airborne disease transmission is strongly short-range, and that there is actually very little long-range transmission of common pathogens like your typical cold or your typical flu. I think when it comes to pandemics, for something to be that contagious, it does sort of need to be more long-range.

I think it is imaginable that we end up in this uncomfortable world where we can't do very much for “normal” disease transmission, but it still is totally crucial anti-pandemic technology. But now there's not really a clear business case for deploying it because people hate paying for prevention.

It's a lot easier to sell someone something if you can tell them, “You're going to benefit from this in the next year,” and see your money back through prevented illnesses and prevented absences and so on, versus, “Hey, this is something that you install just in the event that there's going to be another mass pandemic in the next decade or two.” That's just a much tougher sell.

But I think it's the transmission dynamics and how these diseases actually transmit in real life, under what circumstances, and for what sort of people. I think that's our biggest question mark, and it's very challenging to study.

Yeah, needless to say, we're pretty optimistic, but if it fails, it'll be for reasons like that, right?

Yeah. You could imagine that we think that for a typical Far-UVC installation, you're looking at the equivalent of 1 air change happening every 2 minutes. That translates to 90% of coronavirus or influenza virus being reduced in about 8 minutes, and double that to get to 99%—so about 15 minutes for 99% reduction.

If the transmission dynamic is that you're sharing air with somebody who is ill and, after 30 minutes or an hour, you have inhaled enough infected air to, on average, produce an infection, Far-UVC will totally cut that down. If instead the transmission dynamic is that you talk to an infected person from 2 feet away and get a massive dose, and you are definitely, for sure, getting whatever it is that they have, then that's not really enough room for Far-UVC or any kind of environmental intervention to do much.

You can improve that a little bit by mixing the air and interrupting the airstream between people at that social distance, but it's definitely going to be more challenging. You might still reduce the severity of an infection just by reducing the viral dose. We saw this with COVID: even if you don't fully prevent an infection, if you get less virus in you, you're going to have a less severe infection. Probably quite a lot of diseases work this way as well.

But I think it would be quite unlikely that we would see no benefit at all, whether the benefits are relatively marginal—probably still worth it, especially at a lower price point—or whether the benefits are truly socially transformational, such that we can see vastly less airborne disease. That's the uncertainty. But I think no benefit at all is quite unlikely. I would be very surprised by that.

One hopes that, given numbers like 90% deactivation of pathogens, in an idealistic case, the amount of evidence, both formal and anecdotal, will pile up very quickly and lead to a high rate of diffusion in the built environment. I have heard one objection from people, and I think these interlocutors are overemphasizing the precautionary principle.

But ask the experts. We talked about children and infants being immunologically naïve, and the way you stop being immunologically naïve is to have time in the world, get exposed to pathogens, and have your immune system built up. Is it possibly the case that decreasing people's contact with pathogens is, on net, a bad thing?

I would push back on that quite strongly. The modern formulation of the hygiene hypothesis does not actually posit that you need to be exposed to pathogens to train your immune system.

We now think that the primary immune system training you get as you're growing up is with environmental and commensal bacteria and other microorganisms. There doesn't actually seem to be any benefit to having a clinical episode of illness. I was actually just looking at a couple of studies on this the other day. For example, there was one study on the effect of a child having RSV; it was a neutral-to-negative effect on future illness.

In the extreme case, catching measles wreaks total havoc on your immunological memory. It's purely bad for you. I think the emerging understanding is that all viruses are like this: it is purely bad to catch a virus and get sick. You might not be able to prevent it, but you would still rather it not happen to you at all. If it has to happen, you would rather it happen to you when you're older.

I would much rather my kid catch whatever it is that's going around at 10 than at 5, and I'd rather it happen at 5 than at 1. But I'd really rather it just not happen. There's just no benefit. The immune training comes from contact with the environment and with the world. The world is just teeming with microorganisms; there is absolutely no lack of immune training. So if we just totally ended viral infections, I think that is overwhelmingly good. No downside.

That is great to hear. A thing that I've told people is, if it turns out that there is some optimal level of viral infections that we have to have for a perfectly tweaked immune system, we can always intentionally infect ourselves in the future. If it's just, “Oh, man, my child just hasn't gotten sick enough in the last 9 years.”

I think this is actually called vaccines. I think intentionally exposing people to viruses—we have a technology for that.

Exactly true. On net, we deal with less disease load than we had in historical environments and haven't seen major impacts as a result of that. But we have engineering and pharmaceutical options to raise or lower the level if it turns out that we ever go below the optimal level of illness. Just putting a finger to the wind on how things likely are, I think it's very likely that we are above the optimal level, if there is indeed an optimal level of illness.

Yeah, I think people go too far with the hygiene hypothesis because we can look at the data, or at our lived experience of what it's like to be a human living in our society, and say, “Oh, asthma is up. Allergies are up.” The thing is, those are relatively trivial compared to childhood mortality, which is way down.

Yeah. I think there is just gathering evidence that increased allergies and asthma certainly have nothing to do with viral infections. There might be some question of whether widely deployed Far-UVC is going to mess with the indoor microbiome in a way that affects us. My answer is mostly no, just because microorganisms—bacteria especially, those living on surfaces and not in the air—are extremely hardy.

Far-UVC is generally much less effective on surfaces than in the air. This has not been explicitly studied: what the effects are on the indoor microbiome. But my bet is that if there's a cost, it's relatively minor. In the event that there is a substantive effect, you go outside, and there are going to be germs there. There's dirt, there's bugs; there's no lack of potential exposures.

Yeah. And not to say something spicy on the podcast for the sake of spiciness, but I think the precautionary principle ends up being a really rough way to live life. You can always argue that, in the multimillion-dimensional space that we live in, there is at least one dimension where a given technology would disimprove you, and therefore the precautionary principle says never do anything.

We know what the numbers are for infectious diseases in terms of deaths caused per year. They're horrific. If there is hypothetically a future in which there is a line in the history books—before the ending of flu and after the ending of flu—that will be a world-historical achievement. Again, we're not necessarily 100% expecting that to happen as a result of Far-UVC, but that is something that is possible in the solution set, or possible in the outcome set, given deployment of this. When you compare some percentage of that to some percentage of, “Well, it might subtly tweak the indoor microbiomes,” those are 2 very different numbers in terms of their impact on the human experience.

Absolutely. I'm not saying we shouldn't study it. We should absolutely study it. The space of things that we don't yet know and would really like to know is huge. But you always have to reason under uncertainty and reason about different risks.

This is what I tell people when they talk about photobiological safety: yes, we don't have long-term data; yes, it is reasonable to be cautious about these kinds of exposures; we haven't studied this in this specific population; and yes, there are unknown unknowns, and I cannot fully characterize this risk. But that is just massively underrating the risks from infectious disease.

I think there are also quite a lot of unknown unknowns regarding how bad episodes of viral illness are. I have a strong suspicion that long COVID, for example, is not special, in that quite a lot of viruses have long-term sequelae. I mentioned measles has long-term impacts on immunological memory. There's lots of stuff like this, like MHV virus. I might be saying that completely wrong. We don't necessarily fully capture the downside of an episode of clinical illness, even a relatively mild clinical illness.

It is possible that basically the entire population, for all of human history—or at least all of human history since, say, the move to cities—is suffering under the effects of long flu, and we don't have a word for it because we assume that getting the flu was just something you were resigned to. But in a future where, hypothetically, we are less resigned to that, there might just be far fewer long-term health impacts than there were previously.

Yeah. Some viruses can cause cancers. Personally, anytime I get a bad cold in the winter, half the time I'll be coughing like crazy for 2 months afterward. We don't even fully know everything that we're constantly passing to each other. So I think there are some unknown unknown downsides, and I think there are some unknown unknown upsides as well.

Mm-hmm. I will say, relative to other infection-prevention measures, this one is relatively easy to desist from if we decide that the math doesn't work out in favor of it. You turn the lamp off, and people stop getting doses. It is relatively difficult to desist from, say, vaccines. Obviously, you can stop giving them in the future, but it's tough to remove a chemical change from people after they've been exposed to the chemical change.

Structurally, this is only affecting the top layers of your skin cells, most of which are dead. After you stop getting doses, you stop getting doses.

Yeah. You could imagine that maybe there's some crazy edge case where getting a sufficient dose to the upper layers of skin causes some protein structural change. It diffuses down through the lower skin layer. These are things you sort of have to struggle to think of. At a certain point, reasoning under uncertainty and reasoning about risk just gets kind of nuts.

Yeah. Well, this has been a very informative conversation for me. Are there any thoughts that you would like to leave the audience with with respect to Far-UVC or AeroLamp in particular?

8. Making Clean Air Mainstream

There's a lot of interest in clean air recently. There are big foundations that are putting a lot of money into it. Speaking as a capitalist and as a guy who runs a company, it'd be great if people bought a lot of AeroLamps. But I think in the industry and for the world in general, the really important thing is awareness.

Some sort of global awareness program, some sort of marketing and informational campaign, or some sort of thing like that could easily benefit the world more than almost anything else you can do, right? There's just so little knowledge about this as a technology. To begin with, most people have never even heard of UV for disinfection. But even among people who have heard of UV for disinfection, almost no one has heard of 222 nm. The pitch is really easy.

It's a cool science-fiction technology where you're using special wavelengths to decrease the risk of getting sick. Everyone is eager once they know about it, but almost nobody knows about it. And I think that if you're thinking, “How can I make this more widespread? How can I make it more common? How can I enable the world to get better faster?” information is the main bottleneck.

Yeah. And when we're talking about clean air, I think far-UVC is only one part of the solution. Air filtration and ventilation are also part of that. If you're a parent of a kid, you can lean on your kid's school, daycare, workplace, community centers, or social events that you participate in and ask, “How clean is the air in this building? Can we make it cleaner? Can I help?”

Whether that is far-UVC with AeroLamp or with a different company, we're very cheap, so we think that's attractive. But we're also an open-source company, so in principle, anyone can just take the CAD files published on our GitHub and make their own. Clean air needs to be much more of a thing. There are groups, like a lot of these still-COVIDing groups, and they're fighting the good fight, but it's just not enough. It needs to be much more of a social movement, and there needs to be a broad coalition for upgrading our buildings so that they're not making us sick all the time.

Mm-hmm. So, putting your fingers to the wind here, if the end goal is a social movement and widespread deployment of this in many built environments, if there were hypothetically a well-resourced capitalist listening to this and thinking, “Okay, but where do I spend the first $1 million?” would you want it, at this point, spent on a trial deployment and some papers about that? Or would you want it in, I don't know, a social media marketing campaign to get Taylor Swift or someone to adopt this and achieve adoption that way?

I'm saying something that's kind of absurd, but are we more limited by the formal evidence at this point, or are we more limited by just getting more people to know about it?

I think the latter, but you could easily argue the other way around.

Yeah, I would say the former, just because I think that might be a more robust way to get the word out relative to Taylor Swift doing it. I do think that we are maybe early enough that too much attention could have something of an IFSR effect. So we want to scale responsibly.

I'm a fan of trial deployments. I think we've already started seeing effects, with AeroLamps just being around in San Francisco and Berkeley venues. Also here in D.C., increasing numbers of group houses and event spaces are having these. The more that they're around and people are like, “Oh, yeah, that's just a normal piece of infrastructure,” I think that can function on its own.

I think Taylor Swift talking about far-UVC right now could be very good, very bad, or have no effect at all.

Yeah, honestly, if I were going to pick a celebrity, it wouldn't be Taylor Swift. I think it would be Paris Hilton, because if high-end hotel brands get associated with clean air, I think that would be pretty valuable.

Yeah. Oh, boy. We will be paying for the sort of political-economy consequences of the pandemic for a long time, unfortunately. But one of them is that, in some quarters, there is some skepticism regarding anything broadly associated with public health. Phew, there's much one could say about that.

Well, I think the political angle here is—it is tough, but I think there's a completely nonpolitical, capitalist angle that's pretty feasible. If you run a business that employs people who are highly paid, you're internalizing the costs of sickness there yourself, right?

That applies whether it's someone in your office who gets sick or someone's kid gets sick and then they're out taking care of their kid. I was doing some economic analysis on this a couple of years back, and a significant part of the economic cost of colds is actually caregiver absenteeism rather than direct absenteeism, because kids get sick a lot more. They're more vulnerable.

Yeah, and this is something we saw a lot during COVID: a lot of private companies had interventions that were not state-level mandated, right? This is something we've been trying to do: get in contact with people at Google, because Google is big enough and has enough things going on that it has someone who's in charge of the overall health of Google employees, right?

If we can get someone like that on board, they don't need to do any sort of campaign convincing the average person about these interventions. They just need to do the math and say, “Oh, we think this will benefit Google on the bottom line,” right? And that's a very different sort of calculation.

A lot of financial firms during COVID, quite early on, saw the writing on the wall and implemented clean-air interventions in their offices quite quickly. High-quality far-UVC was not broadly available then, but high levels of ventilation and filtration—companies absolutely saw the business case there.

Obviously, now we're in a different situation. Post-pandemic, things are tougher, but I think it's not impossible. At a certain price point, the business case is quite good.

Generally speaking, I'm an optimist, but the thing that I worry about a little bit is that it could turn into a situation where there's something of a heckler's veto, and the one person in an organization who is most opposed to public health measures might decide to fixate on this as something they definitely don't want. Hopefully, that doesn't happen.

What we've seen is that this is a huge problem when trying to formally run a study. If you're trying to run a study on clean-air effectiveness or far-UVC effectiveness, and we'd like to install these in a space for the study, that is extremely vulnerable to the heckler's veto. You just need one person who's not totally comfortable with it, and the IRB will never let you do it.

It's actually quite a bit easier if a building owner decides, “You know what? We want this. We're installing it.” Generally, in offices, we've found that employees are usually much more on board, and it's the building manager who's like, “Eh, do we really want to spend this money?” So we find that it is often substantively driven by employee demands in the office case.

I think normal technology diffusion or deployment is substantially less vulnerable. The nice thing about that is, if somebody has decided to install this technology because they think it's good and they want to benefit from it, there's nothing stopping you from studying the effects of it later on. So we can still get good evidence without rendering ourselves super vulnerable to the heckler's veto.

And just playing out the micro-politics of this sort of thing, the vaccines have a great individual cost. You have to take time out of your day, go out, get jabbed, and it's a very unpleasant experience, which is more unpleasant than it needs to be. It's amazing to me that we haven't made ShotGuard or something similar the standard of care everywhere.

Be that as it may, there's a visceral unpleasantness to vaccines in a way that there isn't to there being a box in the corner. It doesn't emit anything visible, and it will simply stand there for, hopefully, the rest of time. We're hoping that we successfully get this deployed and that it performs to our expectations—or outperforms them—in the amount of actual impact it has on lived experience.

And thanks very much, Misha and Vivian, for being on the program today. We will follow along with interest as this diffuses into society.

Yeah. It's great to be on here.

Yeah. Great to chat.