Hi, you're listening to Ted Talks Daily, I'm Elise Hu.

Radiation scientist David Brenner believes he can stave off pandemics by harnessing the power and potential of ultraviolet light as we continue to battle the novel coronavirus. Today's show features David Brenner talking with Ted Science curator David Biello at Ted 20-20. Is ultraviolet light safe and can it really be used to kill viruses and bacteria?

Brenner will shed some light pun intended.

Please join me in welcoming David Brenner to share his idea for how we might stop the spread of SARS covid to take it away David. Hey, good afternoon, David, and it's good to be back. It's three years since my first talk, so let's talk for a few minutes about ultraviolet light. So ultraviolet light or UV light is the type of light. It's actually pretty similar to the visible light, but it actually has different wavelengths and that makes it invisible to our humanised.

And it's been known for more than 100 years, in fact, that some wavelengths of UV light are incredibly efficient, killing viruses and bacteria also. So actually, germicide of UV light is pretty commonly used these days to disinfect locations like hospital operating rooms. But the problem we've always had is if people are directly exposed to this conventional germicide of UV light, there are potential health hazards to our eyes and to our skin, and that really greatly limits how and when we can use it.

So what we'd really love is a type of UV light, which both kills viruses but is also safe. And about seven or eight years ago, we realized actually there was such a type of UV light, and that's why you see light, which has an even shorter wavelength, around 220 nanometres. So what we know is that five see light efficiently kills viruses and bacteria, too. But all the available evidence and here's the thing, is that it's safe for human exposure.

So that's true. If IVC Light really is safe and it really does kill coronaviruses, then we have a window of opportunity overhead. Indoor firework lights could be used to kill viruses in indoor spaces where people are present and so reduce the risk of transmission of covid-19. And as we start to reopen after the covid-19 crisis slowly winds down, we hope they're going to be so many situations where people are moving closer together and indoor spaces and hospitals, of course, and nursing homes, buses, planes, trains, train stations, schools, restaurants, offices, shops, theaters, gyms.

The list can go on forever, in fact. So the two questions we need to think about, first of all, is Facebook lights safe and does it really kill coronaviruses? So why is it safe? Well, it's safe because Facebook light really can't penetrate into any living cells in our body. It can't penetrate into our skin, can't penetrate into our eyes. And that's that's purely physics. And that's I'm a physicist by training. So it's nice to see something that's really physics based.

That's the conceptual reason. But over the past five or six years, we and many other groups around the world have done a lot of studies to see is it really safe studies on human skin, on mouse skin and mouse eyes and many different situations and many different countries and all seems to point to to yes, it really is safe. But more than that, actually, this there's a regulatory framework in existence right now. I mean, there are limits as to how much UV light at any given wavelength we can be exposed to.

So the key, of course, is to stay within those regulatory limits. And then the other part of the story as well. Does it really kill coronaviruses? And the answer is for sure it does. As you know, there are many human coronaviruses and most steadily working our way through through them and checking does it kill this coronavirus to to kill this coronavirus, moving up to the the the sars-cov-2 virus. And what we can say today is that, yes, it's very efficient at killing coronaviruses.

So if we see this, it's really safe and it really can kill coronaviruses in occupied indoor spaces. And I think it really does have the potential to be a powerful tool in our battle against covid-19. And I might add, not just that against influenza and against the next pandemic virus if and when it comes. And the sense is a little bit different from a vaccine, which is very specific to one particular strain of virus. So it sounds pretty positive, but that's not to say we should stop using the weapons.

We certainly shouldn't stop using masks. We certainly shouldn't stop practicing social distancing. Fantastic. Thank you so much for that. It does sound like it could be a real a real game changer.

If I can use that cliche, it has that potential. Yeah. So walk us through exactly how this far you see light can kill a virus, but not harm human skin cells or eye cells or whatever else.

Well, the reason is basically it's a physics reasons, as I was saying, that 560 light really can't travel very far in any sort of biological material. So right on the surface of our skin, for example, is a layer of dead cells. And the this fire quite simply can't penetrate through those dead cells and so reach the living cells in the skin and in the epidermis in the dermis. And the same goes for the eye of the very surface of our eyes.

Some liquid called the TIA layer and Facebook like can't penetrate that either. So it can't reach the the living cells in the eye in the corner of deep down in the lens, for example. So there's a real good physics reason why the fire light can't penetrate into living cells in our bodies. That said, bacteria and viruses are very much smaller entities. And so the fire obviously really does have enough range to penetrate them and kill them. So that's why it can kill viruses.

But in principle, it's safe for human exposure.

So it's a kind of defense in depth because we have multiple cells kind of layered down. We're more defended against this particular wavelength than a virus or a bacteria would be. That's right and right on the surface of our skin and our eyes are nonliving cells, so it doesn't matter if the fire services is absorbed their songs, it doesn't reach the living cells in our skin or in our eyes.

Now, the next question, which I think is true for all ultraviolet light, is that in our atmosphere anyway, it creates ozone. And that's a little bit of a other human health hazard. Have you looked into that side of things at all, if there is kind of ozone creation when you have these lights on? Yeah, for sure. And in fact, this this fire obviously is not really at the wavelength that produces very much ozone. So we always measure monitor the amount of ozone that's being produced.

And it's absolutely miniscule. It's it's way, way below the EPA levels for ozone safety. So I don't think that's going to be an issue. So fantastic.

Safe for our skin, safer for our eyes, safe for our lungs. That's a pretty good trip. Let's see what the audience is curious about. We'll take that first question, please. How may you see light be used in settings limited by an easily accessible, stable source of electricity? So this is the power question. Yeah, it's a good question. It doesn't have any special particular needs in terms of electricity. So as long as you in in your indoor setting, you have enough electricity to power regular lights, you'll be able to use five lights.

And sometimes and some of the manufacturers are building in the five week light, in the visible light and into one fixture. So wait a minute, actually visible light light bulbs that also incorporate the our unique wavelength to have a sterilising effect. You are not in one bulb, but the idea of from some manufacturers is to have a fitting fixture, I should say, which has both a visible light in it. And if you see light, maybe one surrounds the other one.

So but it's a single fixture. And other manufacturers are thinking of, well, we'll have two separate fixtures, one one for the visible lights that we already have and one for the five lights. But always with we're thinking about putting these five lights in the same location as where we'd have the visible light.

Is there any limitation on on distance or, you know, however far the light can spread, the sterilization effect will will occur. Well, and just in the same way as when you have a room, you have to figure out what sort of visible lighting am I going to have in this room? If it's a big room, you're going to have to have several lights of a small room, may only have one light. And that's the same thing for 5:00.

If we're talking about a big room, like in an airport, for example, just a very large room, you're going to have to have a few 5V sedates overhead in the ceiling. Got it. Let's have that next audience question. Can you see far unique kill viruses fast enough to neutralize the virus particles born on aerosols in the air? Yeah, that's a pretty central question, we look upon it this way. So if you and I, David, are in a room together and maybe with other people and we're coughing and sneezing, some of us.

So over the over time in that room, the level of aerosols and viruses in the air is going to start to build up. So what we really need is something that will continuously keep that level of virus down. So we'd like ninety nine point ninety nine percent killing in a few minutes and that we can achieve. But the bottom line is to keep the level of virus in the air as low as possible. So that implies that these lights would kind of be always on so that they're always having that sterilization effect.

Well, there could be always on or there could be on a significant fraction of the time. I mean, I don't think it would be very useful to have the lamps on at eight o'clock in the morning for five minutes and then turn it off for the rest of the day, because the whole point is to keep killing the viruses as they're being produced. We don't necessarily have to have it on every moment of the day, but we don't want to have it on just once a day.

Does the sun it must put out wavelengths or it must put out light at this wavelength. Is there a possibility that the sun is providing some of the sterilization in an outdoor setting? Yeah, well, no, actually, it doesn't. So there are three types of UV light that UVA and UVB and you see and they're just different. They're different wavelengths, you see is the one that kills viruses and bacteria most efficiently. The sun produces UVA and UVB and UBC, so they wing their way towards the earth.

But when they get to the atmosphere, the UBC is entirely absorbed in the upper atmosphere, actually, in the ozone layer, in the atmosphere. So down here on the ground, we don't feel any UVic at all. We only feel UVA, which is where we get some suntans from and UVB. And those are not very efficient at killing viruses and bacteria. Gotcha. So we only get the sun burning. In my case, we just get the sun.

We don't get it. And yeah, there's no doubt that UVA and UVB kill a little bit of bacteria and viruses, but not much. And anyway, we believe the whole story really is indoors. I mean, that's where most of the transmission from from from one person to another occurs. There may be some outdoors, but it's pretty limited compared to indoors. That's right. I mean, I think my top concern as a New Yorker is a subway, which is very indoors.

They are using UV light, but it's this UVA or UVB light. Right. And they can only use it when humans aren't present. So in the New York MTA system, they are using conventional germicide or UV light, which is you, AVC, as I said in my introductory words, that has the potential for for health issues if it's directly exposed on people. So what the MTA is doing is at the moment, the MTA is closed down between I think it's 1:00 a.m. and 5:00 a.m., something in the wee hours.

So they're moving the conventional germicide and UV lights into the into the buses and into the trains and essentially sterilizing the trains and buses overnight, which is a good thing. But come 5:00 a.m. in the morning, you have a nice, clean subway car. But five, 30 in the morning, when people start walking into that that subway car, it's over the course of the day, it's going to become more and more contaminated. So what we really want is something that can be used more or less continuously during the day when people are around.

So take us take us back in your own personal journey with far UVic, like, when did you first realize that this had this potential to to combat all these these troubling pathogens? Well, we we were originally thinking not about viruses, but about bacteria, which was both both nasty pathogens, and my original motivation was that I had a friend who passed away from a drug resistant bacterial disease. And I was thinking long ago that anything physics can try and stop this problem.

So we thought very much in terms of reducing surgical site infections in hospitals by killing drug resistant bacteria, but again, with the same idea that it's going to be safe for human exposure. So the first few years we worked entirely on bacteria and then two or three years after that, the penny dropped. And actually we could use this for viruses to viruses are also very, very small like bacteria. And there was no covid-19 at that point. So we were particularly thinking about influenza.

And we should never forget that influenza is a is a very, very nasty virus, which kills a lot of people every year and no doubt will continue to do so. So we've been slowly working the last three or four years in the influenza world. So then come the beginning of this year and covid-19 appears, then it became immediately apparent to us that the ideas that we'd have for influenza were going to be applicable to covid-19 because again, it's transmitted from person to person, primarily in the influenza case by airborne routes.

So all the concepts that were there were developed for influenza seem to be applicable to the covid-19 crisis. Great news, and I think we should get these into hospitals stat that seems like the first to great application and has many co benefits, but I know we're running out of time. So let's try to get in one more audience question before we have to wrap up. So from Stephen Tronic, we live in a symbiotic relationship with bacteria, many of which are essential to life with this, create such a sterile environment that it would ultimately be harmful to us.

Yeah, well, that's a really good question, because it's undoubtedly that there are bad bacteria, which I was just talking about, like MRSA, but there are good bugs, too, and they are essential for us. So most of the the microbiome that help us are inside our bodies are inside our gut, for example. And that's not going to be an issue because the fire, obviously, they simply can't reach into into the guts to penetrate into the body.

As we talked about, there is a skin microbiome actually on the on the very surface of our skin. And that's something that we think about a lot. But if you think about it, how many times have you washed today? Many. So that is going to be more damaging to the skin microbiome than five sealife will be. So what we know of the skin microbiome, by definition, it's really tough, can resist a lot. And even when it's removed, it comes back pretty quickly.

So we don't think that the skin microbiome is going to be a significant issue. And that's why we keep washing our hands even once these far unique lights become available. So I think we have time for one final audience question. Let's see if we can sneak it in. From Terry Moore, What problems need to be solved to make this technology happen now? How can the tech community help? Well, that's a very good question from a TED friend, and I think the the biggest problem needs to be solved now, and we've alluded to it in our conversation, is building up the capacity for these lams industry really only started building these lamps in the spring.

So the capacity really isn't there for the millions of lamps that there is a demand for right now. So there are a few aspects for that. One is, well, it would be really nice if there was a simpler, cheaper technology for producing these lamps. The lamps are not particularly expensive and they're not particularly complicated. But if it could be made much cheaper and much simpler to manufacture and I'm thinking perhaps particularly about the same way as LEDs slowly are replacing conventional light bulbs and LEDs, but have the potential for replacing the current type of fire.

UBC light would be easier to to make, probably cheaper, probably longer lived. So the science community, I think, could certainly be putting a little more attention to different technologies to make the fire UBC production capacity happen faster and happen cheaper. Fantastic. Well, thank you, David, for joining us and sharing this ray of hope in these pandemic times. Thank you so much, David. It's been a real pleasure. Thank you.

Parks.