This Podcast Will Kill You - Special Episode: Carl Zimmer & Airborne

Episode Date: August 5, 2025

In the first years of the COVID pandemic, a debate raged: was the virus transmitted via respiratory droplets, or was it airborne? For some, this distinction seemed overly technical, pedantic even. But for others, it represented decades of dismissal and missed opportunities - opportunities that had cost untold lives. In this week’s TPWKY book club episode, renowned science writer and journalist Carl Zimmer joins us to discuss his latest book Airborne: The Hidden History of the Life We Breathe, which uncovers the long-forgotten story of an entire field of study - aerobiology - and the pioneering scientists who discovered life where there was thought to be none. Tune in for a fascinating conversation about why airborne transmission matters and the incredible work that some researchers are doing to breathe new life into its study. Support this podcast by shopping our latest sponsor deals and promotions at this link: https://bit.ly/3WwtIAuSee omnystudio.com/listener for privacy information.

This is exactly right. There are already enough things charging your card every month. Dinner should not be one of them, which is exactly why Blue Apron is now subscription-free. You heard that right, Blue Apron no longer requires a subscription. You can order meals when you want them and skip when you don't without adding another recurring charge. Blue Apron meals are designed by chefs and arrive with pre-portioned ingredients, so there's no meal planning and no extra grocery trip. Order now at Blue Apron.com. Get 50% off your first two orders plus free shipping with code this podcast 50.

Terms and conditions apply. Visit blue apron.com slash terms for more information. You're listening to a podcast. So you're doing something else too, like maybe scrolling home listings on Redfin, saving places you like without thinking you'll get them. Because that's what house hunting has become. But Redfin isn't built for endless browsing. It's built to help you find and own a home.

Redfin agents close twice as many deals as other agents, which means when you find a place you love, you've got a real shot at getting it. Redfin helps turn saved listings into real addresses. Get started at redfin.com. Own the dream. Busted appliance? This is your sign to upgrade.

Shop at Lowe's to get up to 35% off and next day delivery on hundreds of major appliances. Lowe's, we help, you save. Valid through 318, wall supplies last. Selection varies by location. Order by 4 p.m. Available Monday through Saturday. Subject to availability.

Fees, exclusions and restrictions apply. See loaves.com slash appliance delivery for more details. Visit your nearby lows on Renier Avenue South in Seattle. Hi, I'm Aaron Welsh, and this is This Podcast Will Kill You. Welcome to our newest episode in the TPWKY Book Club series, where I get to chat with authors about their latest books in science and medicine. We have covered some great books so far this season and in past seasons, and we've got plenty more excellent books to add to your two-read list throughout the rest of this season.

If you would like to see the full list of books that we've covered so far, as well as get a sneak peek of the books that will be featured later this season, head over to our website. This podcast will kill you.com, where you'll find a link to our bookshop.org affiliate account under the extras tab. There, you'll see several TPWKY lists, including a book club list. Check back on that list regularly, as I'll be updating it throughout the season. As always, we love getting your feedback, whether that's a topic request, a suggestion for a book to feature in one of these episodes, or just any other thoughts you have.

You can reach out to us via the contact us form on our website. Two last pieces of business before we get into the meat of the episode, number one, One, please rate review, subscribe. You've heard us say it a million times, but it really does help us out. And number two, did you know that we are now posting full videos of many of our newest episodes on YouTube? Make sure you're subscribed to Exactly Right Media's YouTube channel so you don't miss an episode. By now, we are all fairly familiar with the concept of the microbiome, the community of microbes that live in a particular environment, such as your gut or your skin. or maybe even inside your belly button.

But how many of you have heard of the aerobioem? We don't often think of the air as a medium teeming with microbial life, but as Carl Zimmer demonstrates in his latest book, Airborne, the hidden history of the life we breathe, that may be a critical oversight. In this book club episode, award-winning science writer Carl Zimmer joins me to discuss the long-neglected science of aerial life.

and the public health implications of this research. Many of you may recall the debate that sprung up seemingly out of nowhere in the first couple of years of the COVID pandemic, when scientists couldn't seem to agree on whether the virus was transmitted via respiratory droplets or whether it was airborne. Why this distinction mattered and how the issue grew so contentious is just part of what Zimmer covers in airborne. By placing this debate in the broader context of the history of aerial biology, he draws a line from the early days of germ theory to the pioneers of this emerging field, from the height of bio-warfare research to a Washington state choir in the first weeks of the COVID pandemic.

Linking together these disparate stories from the history of science, Zimmer presents a revelatory picture of a scientific field you didn't know existed. How might the COVID pandemic have been different if we acknowledged the airborne potential of this virus earlier? What lessons can we draw from this oversight to apply to future outbreaks? What even lives in the air? And why does it matter? We get into all of these questions and so many more. According to a quick Google search, we breathe about 22,000 breaths a day. Breasts that we don't often think about. But after this episode, you'll have a newfound respect for those breaths and the invisible

airborne life all around us. I am very excited to be bringing this episode to you. So let's just take a quick break and get started. Carl, thank you so much for joining me today. Thanks for having me. I have long been such a fan of your work. And I really especially appreciated your latest book, Airborne, which tells this really fascinating story of discovery, dismissal, and then ultimately kind of redemption in the end. To start us off,

can you give us this big picture view of the story that you explore in your book and what inspired you to write about it? The story is about the air and how humanity has slowly come to appreciate the fact that it's alive. In other words, we really are walking around on the floor of a giant living ocean that is filled with trillions upon trillions of organisms, thousands of different species, a few of which we can see, you know, we can, you know, see a goose flying overhead, but for the most part, it's totally invisible to us. And I guess I say the seed of this book came about during the COVID pandemic. I was working at the New York Times, and I, along with my colleagues,

we were just trying to write as fast as we could about this totally new disease. And, you know, it was challenging because scientists themselves were trying to figure out what exactly this disease is like. And one of the biggest stumbling points, one of the areas with the most debate and uncertainty was how it spreads. You had people telling you on TV to wipe down your groceries. I know I did. and just keep your distance from people and you know you'll be fine then there were other there were

scientists a small number of scientists at first who were saying we think this might be airborne world health organization explicitly saying COVID is not airborne and you know it took a couple years and then world health organizations said yeah it's it's airborne and I just thought why was that so hard yeah and the scientists themselves said to me like well, you need to understand the history. One scientist said, you know, history set us up. And so that led me down this path to discover this whole history of this science of life in the air, which is called aerobiology.

Yes. And as you discuss, you know, this, we're living underneath this ocean of all of these different organisms, the aerobium. What can you tell me about the aerobium? Like, who's up there? Who's floating around besides the ocean? the geese that we see. Well, all sorts of things.

The numbers are kind of crazy. I mean, actually, you have to write them down and double-check them because I'm like, did I get that right? Because they're just, so I'll just give you one example. So insects, okay? So, you know, you've presumably seen, you know, some dragonflies flying by or maybe like a little swarm of mayflies or what have you. I mean, it's not unusual to see an insect in the air, but scientists have long suspected

that maybe large numbers of insects fly long distances high in the air, thousands of feet in the air. The problem is you can't see them. And so scientists have invented technology, so barring radar and tuning it so that you can detect insects that are in large numbers that are way up in the air. Lo and behold, there are a lot of insects up there. And just to give you one example,

and there's a study that came out last year from China, where just in a small region of China, they set up some radar systems to look up. And over the course of a year, they recorded 9.4 trillion insects. Just in that place. I can't comprehend that. Yeah, right.

No, these numbers are incomprehensible. When you get to fungi, you walk around in a forest trail, you see some mushrooms, you think you know what fungi are, but you really don't. Because they're everywhere, they're on everything, and they make a living by sending their spores into the air. I mean,

they have adapted beautiful, like little cannons and other devices to get their spores up high enough so that the air can carry them away. And then they can go all the way up to the stratosphere. Fungi alone, they lift up about a trillion trillion spores every year. Again, I can't, I don't know what that means even. Right, right. What do you do with that? also bacteria, viruses, algae, lichen. And again, they probably comprise thousands, 10th of thousands, maybe millions of species. We, you know, we've barely begun to sample this habitat, this living habitat in the air called the aeroboom. And I love how you describe it as an ecosystem of

visitors. You know, this is a, for most of these species, this is a transitory period. If you take one cubic meter of air or something, wherever it is, how often that changes just within a second, within a minute, within a day, it's completely different. Yeah, it really depends for the individual organism on how high they get up initially and what the air conditions are like when they get lofted into the air. The oceans, for example, every time a wave breaks, there are lots of tiny droplets that rise up, and some of them have bacteria, viruses, other marine organisms in them. Now, if there's enough of a breeze, they may get carried up, and maybe they fall right back down after, you know, a few seconds. But it is possible for them to go up and then keep going up.

And then eventually they get so high that they're just riding along, long. long-distance waves, and they can actually go thousands of miles. So they can be floating for days. Eventually, they will land. I mean, it's just a matter of time. But because there's so many things coming up all the time, it's always a very lively space. So like the clouds, for example, every cloud you look at is alive. It's got, you know, trillions of bacteria, something on the order of that. And, you know, the bacteria, there are signs. that they might be growing in the clouds. And that means that they are eating the clouds. So, you know, it's a different way to look at the sky and think about what's up there. Let's take a short break.

And when we get back, there's still so much to discuss. Dinner shows up every night, whether you're prepared for it or not. And with Blue Apron, you won't need to panic order takeout again. Blue Apron meals are designed by chefs and arrive with pre-portioned ingredients so there's no meal planning and no extra grocery trip. There, assemble and bake meals take about five minutes of hands-on prep. Just spread the pre-chopped ingredients on a sheet pan, put it in the oven, and that's it. And if there's truly no time to cook, dish by Blue Apron meals are fully prepared. Just heat them in the oven or microwave, and dinner is ready. And here's the exciting news. Blue Apron no longer requires a subscription. You can order meals when you want them and skip when you don't without adding another recurring charge.

order now at blue apron.com. Get 50% off your first two orders plus free shipping with code this podcast 50. Terms and conditions apply. Visit blue apron.com slash terms for more information. Anyone who works long hours knows the routine. Wash, sanitize, repeat. By the end of the day, your hands feel like they've been through something. That's why O'Keefe's working hands hand cream is such a relief.

It's a concentrated hand cream that is specifically designed to relieve extremely dry, cracked hands caused by constant hand washing and harsh conditions. Working hands creates a protective layer on the skin that locks in moisture. It's non-greasy, unscented, and absorbs quickly. A little goes a long way. Moisturization that lasts up to 48 hours. It's made for people whose hands take a beating at work, from health care and food service to salon, lab, and caregiving environments. It's been relied on for decades by people who wash their hands constantly or work in harsh conditions because it actually works. O'Keefs is my hand cream of choice in these dry Colorado winters when it feels like my skin is always on the verge of cracking. It keeps them soft and smooth,

no matter how harsh it is outside. We're offering our listeners 15% off their first order of O'Keef's. Just visit O'Keef's Company.com slash this podcast and code this podcast at checkout. A timeless wardrobe starts with pieces that are built well from the beginning. From the fabrics to the fit, everything needs to last beyond one season. And that's how Quince approaches design. Quince has all the staples covered, from 100% organic cotton sweaters to premium denim made with stretch for all-day comfort and luxe cotton cashmere blends, perfect for the changing seasons. The quality shows in every detail, the stitching, the fit, the fabrics. Every piece is thoughtfully designed to be your new wardrobe essential. And each piece is made with premium materials in ethical

trusted factories and priced far below what other luxury brands charge. I recently got a pair of Quince's Bella stretch wide-leg jeans, and they are now in constant rotation. They are so comfortable. The fit is amazing, and they come in a bunch of different washes, so I'm about to go order some more. Refresh your wardrobe with Quince. Go to quince.com slash this podcast to get free shipping on your order and 365-day returns, now available in Canada, too. That's Q-U-I-N-C-E-E-com.com. slash this podcast to get free shipping and 365-day returns. Quince.com slash this podcast. Welcome back, everyone.

I've been chatting with Carl Zimmer about his latest book, Airborne, the hidden history of the life we breathe. Let's get back into things. Which certain types of pathogens are more likely to be airborne? Do they share certain evolutionary history or drivers that might make them more likely to be airborne? That's a really good question. And honestly, I don't think anybody has a good answer for you yet.

Part of the challenge is it's hard to really carefully study airborne disease if you're talking particularly about pathogens. Now, certainly there are some very familiar pathogens that are clearly, we know, are airborne. But that's by no means an exhaustive list. There probably are lots of other things that we are not appreciating fully yet. But just to give a couple examples, the biggest infectious disease killer by far is tuberculosis. It's caused by bacteria. And those bacteria are totally airborne.

In other words, they really can't infect people in any other way other than people releasing little droplets that float out. Not just, you know, maybe when they cough or sneeze, but even when they're just breathing. They are going to release droplets, some of which have tuberculosis bacteria in them. These are so good at being airborne that they actually manipulate us. They actually have adaptations to essentially tickle our airway to get us to cough more because that gets them out and gets them into the air, propels them, and then they can float off and infect someone else. And the droplets make their way into the very finest tips of our airway endings in the lungs,

the alveoli. And that's where the bacteria can grow. So tuberculosis kills over a million people a year. But, you know, it's also a huge threat to, in terms of pathogens, it's also a huge threat to our crops. So there are lots of diseases, particularly fungi, that spread through the air in part or entirely. I write a lot about a kind of fungus called rust,

which can just, you know, it can endanger the food supply of whole countries if it really breaks out seriously. So I'm just giving you two examples, but there's a long list. And is there something about airborne pathogens that they all have in common? I would say they're rugged in the sense that they can survive being floating around in the air.

It's not easy to be a pathogen floating around out in the air. It's hard. And there's some viruses that don't last very long, when in their exposed to air. Other viruses can last a really long time, and it might be that they sort of, they have adaptations that let them kind of use the chemicals inside of those droplets that come out of our lungs to sort of shield themselves from the elements. This respiratory droplet versus airborne debate, you know, as you say, really took center stage during COVID, as we all remember. And kind of like you, it seemed baffling. Like, why is this so controversial? Why is this something that

were so resistant to the idea of this being airborne, especially when it seemed like, you know, this research had been going on for quite some time. And before we get into how that controversy started in the germ theory miasma debate, what role did people think the air played in diseases before germ theory? So if you go all the way back to, say, Hippocrates in the sort of the world of Western thought in particular, there was this idea. that, well, obviously, you know, air is essential to us. The Greeks considered it, you know, one of the main elements. Obviously, we need to breathe, but people couldn't really say why.

And yet there was sort of a sinister dark side to the atmosphere. And, you know, like, I mean, we've all, I suppose we've all had that experience walking around. It's, you know, today here in Connecticut, it's a beautiful sunny day. The air feels very lovely. But, you know, there are also days where, like, it smells really, wrong or there's a weird light in the sky because they're wildfires someplace. And, you know, like the air is unpredictable. And so Greeks had this idea that gods could visit curses on them

and they would call these miasmas. And Hippocrates said, sort of took that name and applied it to what he called, like corruptions of the air so that if you breathed in that air, you would become sick. and there were different miasmas for different diseases and even different species could get different diseases because they had their own miasmas. But they were all transformations of the air itself. It had a certain explanatory power. I mean, how was it that, you know,

a bunch of people in the same town all would get the same disease around the same time? You can imagine, well, you know, a breeze just came through and people all inhaled it and then they all keeled over. But that explained plague, and, you know, influenza and, you know, malaria, literally, like, bad air. Like, that's what the disease name means. And so it held on for a long, long time until people who had been discovering and studying microbes said,

no, wait, we think these are responsible for these diseases. And it was a very, you know, it was a very long slog. I mean, to us, in hindsight, it seems obvious. But, you know, this was a battle that started around, 1700 and lasted up until about 1900. So about 200 years of a long drawn-out fight. It seems like a blink of an eye, like Louis Pasteur came in and solved everything, but that's not, that's not what actually happened. But I think it's so interesting to think about myasma and airborne transmission because they seem like almost the same thing, right? Like how was that

distinction made between microbes in the air causing disease and my asthma causing disease? There were a lot of confusing, seemingly contradictory pieces of evidence flying around. So Louis Pasteur, who you mentioned, who was an architect of the germ theory of disease, he actually was the first person to really clearly demonstrate that there were germs floating in the air. I mean, and people said at the time when he was trying to persuade them of this, that this was crazy. One journalist said, this is, you want to lead us into a world that's too fantastic to believe. I just love that line. But he would go outside with flasks and he would catch bacteria.

They would fall down the long neck of the flask and fall into sterile broth and start multiplying. And he did it in Paris streets. He did it in farmland around France. And he even climbed a glacier, which was my favorite episode of this. And he actually initially said that he thought that lots of diseases were caused by these floating germs, by airborne germs. but it didn't really go that way. And what happened instead was that, as scientists definitively showed that diseases were caused by germs, so for example, cholera, not caused by my asthma, as the authority is claimed,

instead it was caused by fibrocholori, like one particular bacteria. And that particular bacteria spread in water. So you have a waterborne disease. And then you have other bacteria that get into food and contaminate food. So you have foodborne diseases. You have bacteria that spread through sex, so sexually transmitted diseases. And on and on and on. So it was like the germ theory disease was taking one disease after another out of the air.

Ah, yeah. And by the early 1900s, you had very prominent public health figures saying, we don't need to worry about the air anymore. like this should be a relief. The air, you know, has been this specter of infections since Hippocrates. They literally said this, and now you don't need to worry. I think that really did keep people from really thinking very much about life in the air. And they also didn't have very good technology for really measuring and capturing life in the air. So that combination really did lead to a real, very strong consensus, starting in the early 1900s, that has endured for,

over a century. Let's take a quick break here. We'll be back before you know it. Anyone who works long hours knows the routine. Wash, sanitize, repeat. By the end of the day, your hands feel like they've been through something. That's why O'Keefe's Working Hands hand cream is such a relief. It's a concentrated hand cream that is specifically designed to relieve extremely dry, cracked hands caused by constant hand washing and harsh conditions. Working hands creates a protective layer on the skin that locks in moisture. It's non-greasy, unscented, and absorbs quickly. A little goes a long way. Moisturization that lasts up to 48 hours. It's made for people whose hands take a beating at work, from health care and food service to salon, lab, and caregiving environments. It's been relied on for

decades by people who wash their hands constantly or work in harsh conditions because it actually works. O'Keefs is my hand cream of choice in these dry Colorado winters when it feels like my skin is always on the verge of cracking. It keeps them soft and smooth, no matter how harsh it is outside. We're offering our listeners 15% off their first order of O'Keefs. Just visit O'Keefscompan.com slash this podcast and code this podcast at checkout. Texting privacy policy and terms and terms. Texting enrolls you for occurring automated text marketing messages. Message and data rates may apply or place. Stop, opt out. Visit ISSA online for details. Excuse me. What do you do for a living? Wait, tables. You like it? Not really.

Do you work out? Every day. Best part of it. of my day. Would you like to get paid to work out? Are you kidding me? How? With ISSA, you could become a certified personal trainer in as little as six weeks. Once you're certified, you can start your own business, work at a gym, or just do it as a side hustle. Some trainers are making as much as a hundred dollars an hour. A hundred bucks an hour. Yes, please. But how do I even find a job as a trainer? That's the best part. There's such a huge demand for personal trainers that ISSA guarantees you'll get a job. I'm in. How do I get started? Just send them a text. Get your free personal training evaluation kit today.

Just text Jim to 3232.32 right now. Get certified in as little as six weeks. And ISSA guarantees you'll get a job. Text Jim to 32323232. Text Jim to 32332. Jim to 32 3232. Why have I asked my electrician I found on Angie.com to bury my pet hamster nibbles in our yard for me?

Because I was so moved by how carefully he buried my electrical wires. I knew I could trust him to bury my sweet nibbles after his eye. untimely end. Nibbles. Gone too soon. May he scurry in peace. Hey, sorry about your pet, but I just wire stuff. Nibbles would have loved you like a brother.

Connecting homeowners with skilled pros for over 30 years. Angie, the one you trust to find the ones you trust. Find pros for all your home projects at Angie.com. Welcome back, everyone. I'm here chatting with Carl Zimmer about his book Airborne, the hidden history of the life we breathe. Let's get into some more questions. There were still some people,

that did remain intrigued by the concept of, you know, living things, the aerobiome. And I want to ask you about one of these, which is Fred Meyer. How did he end up turning what was first a hobby into this whole branch of science? Yeah, Fred Meyer is a really remarkable figure, and is kind of typical for early aerobiology figures, completely forgotten. So, you know, I had to dig into archives to really figure out. what I could about his life. So I had mentioned before about, you know, how there are these pathogens of plants, particularly of crops. So Fred Meyer was a plant pathologist. He worked at the U.S.

Department of Agriculture ever since he was like 20 years old. It was just his lifelong employer. And he was part of this tradition of studying diseases that affected crops like watermelon and wheat and so on. And they were very comfortable with the idea of airborne disease because there are these spectacular crop failures like, you know, the great Irish famine that was caused by potato blight that in part was airborne that organism. So by the early 1900s, plant pathologists, they knew that things moved through the air. They just didn't know how far they could go or high they could go. And so eventually Fred Meyer says, like, I am going to try to figure out. how high and far I can go to catch them.

And this was something that his bosses did not want him to do. So he just did it on the side, on his off hours. And it's kind of spectacular. He would jump into planes, these open cockpit by planes, and he'd have these petri dishes stuck on to handle, wooden handles, and he'd just basically be waving his arms around out of a flying plane in the clouds. and the pilots would just be totally baffled by him. But he'd bring these prejudices back to his lab,

and he would grow stuff. He was catching things. So then he started looking for opportunities to send more sophisticated devices higher and farther. So, for example, Charles and Ann Lindberg, they flew in 1934 across the North Atlantic over Greenland, and he talked them into trying to catch life as well. And they did.

And then there were these explorers who got into sort of metal spheres. They were attached to giant balloons, and they went up to the stratosphere. And so they took along with them, probes that Meyer had to see if life could survive up in the stratosphere. And then on a second voyage, they actually were able to catch stuff up there in the stratosphere. So what's really kind of unbelievable to me is that by 1937, Meyer had assembled so much dead. dazzling work that he was able to talk to government into creating a whole new service in the government, a kind of a centralized lab for life in the air, and he was going to head it. He coined the word for the science that they were going to do, aerobiology.

He came up with that word in 1937 with this plan, and everything was looking great. And then he went on his sort of maiden voyage across the Pacific. in search of life and was never heard from again. So I feel sometimes writing about these people, there's a certain curse that hangs over aerobiology. I mean, I was shocked when that was like the twist in the story, but then also it did feel like fitting in a way. Like, of course this, like there's more things. Like you said, befell these people that, you know, can't quite get their ideas and their evidence to take hold in the public eye, I think in the public facing side. of science. But as you talk about the military side of things, this really did gain hold. There was

more interest in aerobiology and the potential of air as a way to transmit disease and how to protect ourselves from that. And I think it's interesting to think about these two sort of lenses through which people viewed aerobiology. You have, you know, Fred Meyer on the one hand, who's just interested in the rich tapestry of life in the air. And then you have more of the U.S. government interest at the time, in part shaped by global politics, where it's like, but what about bio weapons? What about biodefense? And how did that branch kind of grow more or gain more interest than Meyer's side? Yeah. When World War II begins and then the United States is starting to prepare to enter, there was a serious concern that.

that Nazi Germany might be developing biological weapons that it might use in battle. I mean, they've never been done before, but there was this great fear for decades. There had been a fear that someone might somehow deploy these deadly germs against soldiers or even civilians. So the U.S. government actually started to reach out to these aerobiologists. They would say, well, what do you think are the risks that we face? And so there was one aerobiologist, named Nolan Stackman, who wrote a very long memo based a lot on the work that he and Fred Meyer

and others had been doing, saying, yes, we could be attacked. And here's what could happen. So I mentioned stem rust. So he said, you could imagine someone dropping a stem rust bomb over our farms and wiping out our food supply. And, you know, someone like Stackman, who had been involved in World War I could see like what happens when a lot of World War I

could see what happens when an army loses a food supply, because Germany actually had its own potato blight, this airborne disease that was devastating to its food supply, and that may have really tipped the balance of the war. So he said, we need to be aware of that. We need to have, like, plant pathologists, looking out for attack and so on. But then it's quite amazing. Like, in writing is like, we have to explore developing our own weapons. It would be remittal of us not to. It would be irresponsible for us not to start building our own arsenal. You know, it's kind of like the nuclear sort of logic. Like, well, if they're going to be building him, well, we should too as defense. And he said, here's how you could like go after Japan. You know,

they have these rubber plantations for their tires, for their vehicles. Well, here's a microbe you could drop on their rubber plantations and wipe those out. He really thought a lot about this. And there were other aerobiologists, William and Mildred Wells, a husband and wife team, who in the 1930s had been showing how people can spread diseases to each other through the air. And William Wells in particular had developed all sorts of really elegant devices to demonstrate how germs can float in the air and also then to sort of measure how much you would need an animal to inhale, to die. The military, you know, at Camp D.Trick, they started building very similar devices.

They took secretly, without his awareness, they secretly started building these devices. And so to figure out, well, instead of saying like, well, how do we understand these airborne diseases to protect people, how do we build better weapons? Like, what's the minimum dose we need of anthrax in the air to kill these mice? Right. And they did all this research in a giant building, literally called the aerobiology building. And, you know, the United States, the Soviet Union, and other countries, you know, would go on for decades to build huge stocks of biological weapons, all firmly based on this new science of air biology. I mean, that is such an interesting aspect of this story where you have this acceptance of this idea of how much the air can contribute to the spread of disease and the potential there. So we have that happening in the military side of things.

What was happening in the more public-facing side of science and aerobiology with the Wells's? The Wells has come into the world of aerobiology kind of in a very peculiar sort of sideways manner. You know, William Wells, he gets a bachelor's degree at MIT in sanitation, and he goes off to study typhoid and water, and he gets into studying how it is that oysters actually can be really dangerous to eat because they filter all the bacteria that cause typhoid and you eat them raw and you die. And so he was trying to figure out, how do I purify your oysters and so on?

And then he gets pulled into World War I. His job is to clean the water for the soldiers. And so he is protecting American soldiers by providing clean water. But meanwhile, they're dying of influenza, not a waterborne disease. And it's not really clear how it's spreading. But I think that the seeds were planted there

that he thought, maybe this is airborne, despite that prevailing view that diseases are not airborne. So he comes back from the war. He's married Mildred Wells. She had gotten a medical degree, but she didn't practice medicine. She was raising their son who probably had some sort of psychiatric disorders, just judging from medical files. I was able to come across later.

They have a good run in the 20s. He continues studying oysters. He gets famous for being the oyster godfather, he's figuring how to breed oysters. And then the Great Depression comes and he's out of a job. Mildred somehow gets a job studying the epidemiology of polio. And she actually contributes to a book about it. And she develops this idea that maybe polio is being spread through the air.

She doesn't really develop it a lot in her writings, but it definitely influenced William Wells. He gets a job at Harvard teaching. He's terrible at it. I mean, I'm not making it up. Like the dean of the school, Bubble Gelf, says this is something that Wells does very badly. Like it's in writing. And he in particular had a very difficult time with communication.

And just he would get into arguments with people or long, long monologues. Mildred was really fierce herself. They didn't make friends, put it this way. They're brilliant, but they alienated everybody. But at Harvard, they start to do some experiments that actually, establish some of the basic ideas about airborne infection. In other words, that, you know, when you breathe, you are releasing droplets and some of them can have viruses or bacteria in them. They can float around for hours, maybe days in the right conditions, primarily in indoor spaces.

And they even show that you can use ultraviolet light to kill them in the air. First, they do this with experiments on animals. But then when they moved to Philadelphia, they put ultraviolet lamps in a school. And in 1940, there's an outbreak of a disease who's been hearing a lot about recently, measles. At the time, there was no vaccine, so people were just very resigned

to this terrible disease sweeping through. The Philadelphia School was substantially protected from this measles outbreak by these ultraviolet lamps. And, you know, this was not stuff they did in secret. This was all heavily reported. People were very excited. They were like, wow, like we, maybe we don't have to worry about a new 1918 flu pandemic again because we know that influenza is airborne and we have a way to protect ourselves from it.

And yet, nobody knows who the wells are these days. They just, they crashed into obscurity later on. So, you know, they may not have died in a plane crash like Fred Meyer, but they have had their own crash nevertheless. That's another kind of mysterious disappearance of its own, like why this work that could have such profound implications for public health just kind of went away. And I'm curious to hear your thoughts on why that might be, you know, was part of it any sort of taint that like the military's interest in bio-weapons, like was that part of it?

You mentioned like antibiotics and vaccines and sort of the decline is like, we're winning the war against infectious disease. What were some of the factors at play there? Yeah, I think there are many of these factors that you mentioned that were all at play. I think that, first of all, epidemiology and trying to establish how diseases get from one person and another, it's just difficult science. You need just the right opportunity and just the right conditions. You need to design your experiments, just right to get really clear, compelling evidence. And so, you know, If you're talking about water, like let's say that sewage is flowing into a river and a city is getting its drinking water supply just downstream and there are a bunch of typhoid cases. Like this literally happened in Lowell, Massachusetts in the 1890s.

You can, you know, you can say like, hey, let's stop getting our drinking water from there, shall we? And then lo and behold, the typhoid goes away. You know, like, so like there's a certain sort of control to that. Whereas the air is like, it's very hard to control. It's elusive. And while there is a lot of life in the air, like it's dilute, you know. So you might be breathing, you know, 2,000 times a day, hundreds of thousands of times a month. But, you know, it could just take one of those breaths for you to take in COVID or what have you.

And boom, you've got an infection. So I'll just say it is hard to study. But, you know, on top of it. of that, I think there was this consensus that had really built in and people were very reluctant to shift away from it. So they just, they would say, like, you need to really, really persuade me that diseases can be airborne. So they really refused to look at good evidence. And yeah, and I think with the biological warfare research, it's arguable that a lot of the best evidence that diseases are, in fact, airborne was being done in secrecy. It was being done,

you know, as classified research. And some of that is still classified today. So instead of being an open science, a science that was really like focused on human health and, you know, and understanding ecosystems, a huge amount of effort in the air biology world went into building weapons. And so maybe people thought like, well, I suppose you could build a weapon that could really create an airborne disease, but that you'd need human intervention as opposed to just nature. So there were a lot of different, a lot of different reasons. But what's remarkable is that even at the start of the COVID pandemic, a lot of these assumptions and a lot of these misunderstandings and so on that you can trace back a century, we're still present in public health guidelines. Yeah. And how public health

organizations dealt with the COVID pandemic. They were still in place. Right. And the message was respiratory droplet transmission. Well, and that, just to clarify, what they were talking about is like if someone is just a cough in your face and like a big old drop, it goes, boom, and just hits you in the face, that's what they're talking about. Whereas what someone like William Wells was talking about was saying these tiny droplets that leave your nose in your mouth just as you breathe or talk or sing, and they can float. So those big droplets, they drop to the ground because they're so heavy, the thinking was.

But in fact, there's all these tiny droplets, which can themselves have COVID viruses or influenza viruses or, you know, tuberculosis bacteria in them. And, you know, they can fill a room, if it's not well ventilated. They can fill a room like smoke. Think of those as viruses. And this is something that seemed to emerge during the first SARS. epidemic in 2002, 2003, with this idea that there was evidence for potential airborne transmission of this virus, why didn't we remember those lessons? Is it just more of the same thing, like just the stickiness of this idea that airborne transmission is a minor, plays a minor role in the spread of most respiratory pathogens? Like, why didn't we remember that? Yeah, it would have been

great if we had. So in the SARS epidemic, what's really remarkable is that, you know, as this coronavirus, another coronavirus was emerging as a human disease, there were a few scientists who were getting dissatisfied with the standard view held that these must be spread by kind of, you know, contact or very short range droplets. They're like, no, this is like spreading, it seems like it's spreading through like buildings. And they had to rediscover William and Mildred Wells. These people were like, huh, I keep seeing these references to William and Mildred Wells. Like, who are these people? Like, nobody knew who they were. And I talked to this one University of Hong Kong researcher named Yugo Lee, who is just a, you know, now is like a world

expert on airborne infection. And at the time, he was trying to help understand SARS. And he was like, hmm, it looks like Wells has written a book. Wells wrote a book in 195. Nobody in Hong Kong had it. and the only place he could find it was in one university library in the United States, and he asked them to photocopy it. This is like the early 2000s. So they photocopied the whole book for him, and they mailed it to him. And then so he gets this big stack of photocopied pages, and he starts reading it. And he says, ah, okay, now this is making sense.

These are droplets. Okay. And it's crazy to think that he had to go to these measures to discover what had been widely reported and widely known in the 1930s, you know, that he had to dig this back up. And thank goodness he did because then he did a lot of research on SARS and really demonstrated how the way it was spreading through buildings and hospital awards and so on,

it really did look like it was behaving like what William Mildred Wells was talking about in airborne disease. The problem is, among other problems, is that SARS, it's sort of a good news, bad news thing. SARS was able to be controlled and then eradicated. Because all you needed to do is as soon as people showed symptoms, that's when they started becoming infectious. So you'd just be real careful about isolating people, you know, supporting them.

Some of them died, you know, about 800 people died of SARS worldwide. But they rained it in. And there is no SARS anymore. So it wasn't something that you could be sort of studying year in, year out. It was just this one terrible moment in history. And, you know, there were these clues, you know, these studies that said like, hey, maybe this is airborne. But, yeah, I'd say that it didn't really penetrate. You know, all the pandemic preparedness that came afterwards was all based on this idea that it would not be truly airborne.

That shift did eventually happen during the COVID pandemic. What came to a head to then finally change the tides to, to people realizing that airborne transmission is a real, not just a real possibility, but like at the forefront of what is maybe spreading a lot of these cases. So there were people like Yugo Lee early in the pandemic in early 2020 who would say, you know, this seems to be spreading like an airborne disease. And they were just being emphatically ignored by public health officials or, you know, people were just saying, you know, they're just saying, no, no, there's,

the evidence says otherwise. And so this group of people, at first just a, you know, just a couple dozen experts, they got together and they tried to change the World Health Organization's view on this. WHO didn't budge. So then they went public. They started trying to like gin up support. But it really took like a whole string of outbreaks and studies on those outbreaks to really demonstrate it.

I focus on one in particular. that struck a choir in Washington State, where on March 10th, 2020, about 60 people gathered together, one night to sing. And they were being careful. They were doing everything they were supposed to be doing. And no one seemed to be sick. No one was coughing.

But there was an infected person who was breathing. And then, you know, over 50 people came down with COVID in the next few days. It took time, unfortunately, to sort of to become aware of these outbreaks. and then for these airborne advocates to say, like, hey, we're going to investigate these as sort of cases of airborne spread, see if we can test this hypothesis. And then eventually enough evidence emerged that satisfied a lot of people, and then the consensus shifted. I mean, I won't, you know, there are people who will still say, like, no, I'm not convinced,

but, you know, I would say, like, that most, certainly most scientific societies that are, relevant to this and so on have all agreed that it's airborne. But yeah, it took a long time. It did. And it does, I think, beg the question of what could have been different if we had recognized this before COVID? I mean, not just before SARS, but just at least before COVID. If we had recognized it, there would be at least the opportunity to deal with the disease as an airborne, disease, you know, that takes a lot. I think another reason for the slow take-up of, you know, recognizing this disease as airborne is that it's simpler to deal with a disease that is just caused by short-range droplets or by contact. It is just, it's a simpler process. If it's all

around you as like a smoke, then you've got to do different things. For one thing, we might have made sure, really sure that we had a real stockpile of protective equipment, which we didn't. So, you know, people were just desperately reusing N95 masks, which is crazy. We could have invested in ventilation systems, in schools and other places. We could have had ultraviolet light in places where ventilation wasn't a good solution. I mean, you know, these advocates of airborne disease, they were saying in the summer of 2020, like, we can get kids back in school this fall if we take airborne infection seriously, if every classroom has, you know, at least an air purifier or something. But, you know,

the ventilation of schools, unfortunately, is terrible. So I think across the board, a lot of lives would have been saved if we had immediately responded to COVID, recognizing the possibility that it was airborne and really acting on that. Has this recognition that not only airborne transmission of COVID is a possibility, but just the recognition of Wells's work overall, the Wells's work, has that kind of revitalized the field of aerobiology? Yes, it definitely has. And these scientists who felt like they were just shouting into the wind, forgive the pun, they really are trying to seize the moment. There are our whole research centers being built to study airborne transmission and they are trying to translate these findings into real meaningful policy that

can protect people, not just from new diseases, but from present ones. You know, measles, tuberculosis, influenza, chickenpox. Like, there are lots of diseases that can spread through the air, at least to some degree. What it hasn't led to has been real mandates. Like, there's no country anywhere yet that officially has. standards in place, you know, like if you're going to build a building, this is what you have to do to keep the air safe. It doesn't exist yet. If you walk into a building, you kind of expect that, you know, there are building standards about the rebar and the materials that they're used. You know,

you don't expect that they contain poisons that are going to waft through the air and kill you because there are standards. But there are no standards yet for how to keep the air clear of pathogens. They've suggested mandates. No one's taking them up quite yet. It'll be interesting to see what the future holds in that regard, as long as people are allowed to continue to do basic research on this sort of thing. Which is an open question right now. It's an open question, yeah. Well, I really enjoy chatting with you about this. I loved your book, Airborne. Everyone, go check it out. And thanks so much for taking the time to chat with me today. Thanks. It's been a real pleasure. Huge thanks again to Carl Zimmer for taking the time to chat

with me. This was such an eye-opening conversation. If you enjoyed today's episode and would like to learn more, check out our website, This Podcast Will Kill You.com, where I'll post a link to where you can find Airborne, the Hidden History of the Life We Breathe, as well as a link to Carl's website where you can find his other books. And don't forget, you can check out our website for all sorts of other cool things. including but not limited to transcripts, quarantini and placebo-rida recipes, show notes and references for all of our episodes, links to merch, our bookshop.org affiliate account,

our Goodreads list, a firsthand account form, and music by Bloodmobile. Speaking of which, thank you to Bloodmobile for providing the music for this episode and all of our episodes. Thank you to Liana Squalachi and Tom Brifogel for our audio mixing. And thanks to you, listeners, for listening.

I hope you liked this episode and are loving being part of the TPWKY Book Club. A special thank you, as always, to our fantastic patrons. We truly appreciate your support so much. Well, until next time, keep washing those hands. Get a little out there, into the big heart of Nevada, where you can go off road and off the map, on two lakes or on horseback,

dip into hot springs and dive into deserts, climb a mountain, or make your best effort, See thousands of stars in some of the darkest skies. Stake out haunted hotels. Can you make it to sunrise? There's always something new to see because we've got plenty of space to just be. Plan your trip at travel Nevada.com.

You know that feeling when a story just grabs you and won't let go? That's the kind of drama that's waiting for you on Disney Plus Hulu. Mysterious post-apocalyptic thrillers like the acclaimed Hulu original, Paradise. Action Adventure Drama, like Daredevil Born Again and iconic medical dramas like Grey's Anatomy, or maybe you want your drama with a side of comic relief, with shows like high potential. Find the drama you want on Disney Plus and Hulu with a bundle subscription.

Terms apply. This is Matt Rogers from Los Culture Eastas with Matt Rogers and Bowen-Yang. This is Bowen-Yang from Los Culture Rees with Matt Rogers and Bowen-Yang. Hey, so what if you could boost the Wi-Fi to one of your devices when you need it most? Because Xfinity Wi-Fi can. And what if your Wi-Fi could fix itself before there's even really a problem? Xfinity is so reliable, it does that too. What if your Wi-Fi had parental instincts?

Xfinity Wi-Fi is part-nanny, part-Ninja, protecting your kids while they're online. And finally, what if your Wi-Fi was like the smartest Wi-Fi? Yeah, it's Wi-Fi that is so smart. It makes everything work better together. Bottom line, Xfinity is smart and reliable. You deserve the peace of mind of having Wi-Fi that's got your back. Imagine that.