The economics of putting germicidal light in every room, with Misha Gurevich and Vivian Belenky of Aerolamp

**Patrick McKenzie** (0:02)
Welcome to Complex Systems, where we discuss the technical, organizational and human factors underpinning why the world works the way it does.
Hi, everyone. My name is Patrick McKenzie, better known as patio11 on the Internet. As long time listeners of Complex Systems will know, I think that far UBC is one of the sleeper picks for among the most important technologies getting developed today. Far UBC 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 researcher at Columbia University. Thanks very much for coming on the program, guys.

**Misha Gurevich** (0:56)
Yeah. Good to meet you.

**Patrick McKenzie** (0:59)
Good to meet you as well. So just 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 slash biology level, and hopefully on the social slash technology level?

**Vivian Belenky** (1:16)
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.
So essentially a pathogen or any microorganism, anything without significant protections like humans and animals, is going to be inactivated. So it's still in the air, but it can no longer replicate. And this works extremely fast. So 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 two, in your space you can get the equivalent of 30 to 50

**Patrick McKenzie** (2:20)
And this is just a wavelength of light, which happens to be invisible. So it's something that we get in sunlight already, presumably, right?

**Vivian Belenky** (2:29)
No, actually. So, yes, so sunlight is primarily UVA and UVB. UVB in particular is what we're most worried about when we're worrying about risk of skin cancer and cataracts. But UVC is actually completely blocked by the ozone layer.
And this makes sense because UVC is quite efficient at inactivating microbial life.
Probably the surface of our planet would look very different if it was present here on Earth. So there is no UVC in sunlight. Sunlight is germicidal, just like UVC, but to a much lesser extent. So it's true that while sunlight does kill germs, it does it because there's just so, so, so much more sunlight than there is from any UVC lamp. That even though sunlight is only mildly germicidal per photon, it can still do the job.

**Patrick McKenzie** (3:25)
The legal beagle in me has to say that Oliver Guendo Holmes was empirically disproven by the science. Sunlight is in fact not the best disinfectant. But okay, so this is a interesting wavelength of light. I personally have done a little bit of the reading and am relatively well informed by the safety story, but I think that the typical member of the audience probably isn't.
So what is the sort of like chemical slash biological reason that this is safe for us? You've mentioned that it gets blacked by basically any proteins, so proteins in our skin and epidermis layer presumably, but how is it safe to, for example, look at?

**Vivian Belenky** (4:09)
Right. So this is actually much more of a mechanical story than a chemical or biological story.

**Patrick McKenzie** (4:16)
Okay.

**Vivian Belenky** (4:16)
Essentially, you know, it's not good for living cells to be exposed to UBC of any wavelengths.
You know, but the difference is that humans have a 20 micron sick layer of dead skin cells that are chock full of proteins, that essentially absorb all far UBC. And I should say this is unique to far UBC, the wavelengths of 200 to 235 nanometers, principally 222 nanometers, which is what is most virtually viable right now. Longer UBC wavelengths, 254 nanometers, 265 nanometers, which are used in water disinfection. These do not have so significant protein absorption. So they are, I'm not going to say they'll give you cancer. Relative to UBB, 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 the far UBC. So this high protein absorbance, it is due to the stratum corneum, the outer layer of the skin, it absorbs almost everything. And what is not absorbed is only absorbed in only the very upper layers of the skin. And those skin layers tend to generally slough off and become part of the stratum corneum within typically a couple of days. So I've never seen a study that showed any significant biological activity down at the basal skin cell layer, where you would just don't worry about cancer if there was 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, brow ridge.