Short Wave - Could air pollution make your memory worse?

Episode Date: June 16, 2026

Summer is here, your windows are open and the smell of…car exhaust and the latest wildfire are wafting in. This air pollution is harmful to almost every organ, including the brain. Today on Short Wave, we talk about one way air pollution may cloud your memory.Interested in more episodes about how where we live affects us? Email us your question at [e-mail] and we may turn it into an episode!Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave.See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Hey, shortwavers, Emily Kwong here. And Angela Zang. With our bi-weekly science news roundup featuring Mary Louise Kelly from All Things Considered. Hello. Good to be back with you. Oh, thank you so much for joining us. We are going to start with something kind of serious today.

I know, shocking because we're such clowns. But we're going to be talking about air pollution and health, specifically brain health. How are you feeling about your? your memory these days? I am great on things that happened years ago. I am not so great on where my car keys were left this morning. It is some complex science. Yeah, yeah, yeah. Memory is a complex thing, and our brains are fragile instruments in that way. So we're going to talk about that. And our second and third topics are about critters and what they can teach us about the world around them. We're going to dive deep to Will Graveyards, and then we're going to zoom in to ancient squirrel droppings.

if you can believe that those words can even go together. I will come to believe them after you share. Share these two things I definitely did not have on my reader this week. It is such show and tell. Shortwave Roundup is like, here's some treasures that we harvested for you. Yeah, you know what they say. I mean, you know, you are what you eat or at least poop out what you eat. And people may study it hundreds of years later.

So today on the show, we've got stories on air, land, and sea. You're listening to Shortwave, the science podcast. from NPR. All right, Angela and Mary Louise, our host, we have got a lot to get into. What do you want to do first, Mary Louise? Let's do the air pollution and how it can affect your memory.

Tell me more. So the study I have for you today is about these really, really tiny particles of air pollution, like 30 times smaller than the width of a human hair. And these particles are released by wildfires and car exhaust, among other things, and they're bad for your heart and your lungs,

and they can also get directly. to the brain through the blood. That sounds awful. What do we know about how they affect, say, a person's memory, though? Yeah, so to study how air pollution affects the brain, researchers used a database containing information about black Americans living in California. The researchers looked at how much air pollution, someone may have experienced based on their home address, and then looked at their cognitive test scores.

And while we know pollution is bad for the brain in general, what the researchers found is that it also affected a specific type of memory. The people who had been exposed to more pollution over the years had weaker semantic memory. So really, that long-term pollution looked like it was aging the brain's memory ahead of schedule. That's Catherine Conlon, a study author. She's a professor of epidemiology at the University of California, Davis.

She told me that semantic memory is how your brain stores information. So let that New Delhi is the capital of India or that 3 plus 2 equals 5. When that's effective, we can think about how that's the kind of thing that might chip away at a person's independence or our ability to have the quality of life that we would hope to have. But how do they know it's air pollution and not some other factor in these people's lives? The researchers did control for differences in education and income. But when it comes to geography, you're right. It is hard to separate air pollution from things like noise exposure, which could also influence brain health.

They can't say for sure that it's air pollution that is leading to worse memory. But including Black Americans in research, which is what the study did, means that solutions can hopefully reduce inequity, since they're almost twice as likely as white Americans to have dementia and they're more likely to live in polluted or redlined neighborhoods. Okay, so now we have this research. What do we do about it, Emily? Well, it definitely gives policymakers and urban designers something to chew on. But in the meantime, there are things individuals can do. right now. Catherine said to

quote, know your air by checking your local air quality on your weather app. And then during wildfires or smoggy days, keep your windows closed and buy or make your own air pair of fires. And then lastly, don't make your indoor air worse. So skip the candles and gas stoves if you can.

No, I love my candles. It's a few less candles. A few less candles. Okay, let's turn to topic number two from up in the air to under the sea. We are going to a whale graveyard. I'm trying to picture this, Emily. Yeah, it's a really cool place. So when whales die,

many fall to the bottom of the sea. And when they land, their carcasses become an energy-rich habitat, drawing a wide variety of organisms from across the deep sea to feast. Scientists call these sites whale falls. Whale Falls, because they're fallen whales. So now I'm picturing like a deep sea buffet for all these way deep down creatures. Yeah, who are used to just getting like snacks drifting down to the bottom. So it's really cool. And a research team in China may have found the deepest and most extensive whale graveyard in the world, located in the Diamantina zone in the Indian Ocean. The team published these findings in the journal Nature. And what does this whale graveyard actually look like? Yeah, so you can picture a nearly 750 mile long stretch of whale fossils. These are bones

that are shaped like chimneys or even giant cigars. And the oldest fossils were 5.3 million. years old. It's pretty old. So old. And during dives with a submersible, the team also discovered five of those whale falls, these five whale carcasses teeming with scavengers. The team saw a whole thicket of microbes, squat lobsters, brittle stars, and jellyfish, and even species that may be new to science, like bone-eating worms. Bone-eating worms. Okay, Emily, Emily, you just said, this is the Indian Ocean that we're in, right? Is there something specific about that, Angela, that so many whale carcasses end up in this particular part of the Indian Ocean?

One reason offered by the lead author, Shao-Peng, based of the Chinese Academy of Sciences, may have to do with the shape of the seafloor in this part of the world, or maybe even the currents that are around it. The surface currents and the deep currents can funnel or concentrate those carcars on the sea floor. Biologists, by the way, are so excited about this finding, because these ecosystems are incredibly unique. Stephen Godfrey, a paleontologist at the Calvert Marine Museum, who was not a part of the paper, said the study reminded him of a trailer

for the first in a series of epic movies, and that he hopes there will be many more of these blockbusters to come. Here, here. Okay, that brings us to our last story. You mentioned prehistoric mysteries. You mentioned ancient squirrel poop. Where is this going, Angela? All right, so we got to go.

back in time to the Pleistocene epoch. This is one of the most critical turning points in Earth's history because starting around 12,000 years ago, Earth went from chaotic cycles, so ice, warm-s-dolls back to ice, to the Holocene, which is our current epoch. And a study out this week in Nature Communications zooms in on the Yukon in northwestern Canada where we find an unassuming critter, the Arctic ground squirrel. The study's lead author, Tyler Murci, refers to them this way. They're kind of like accidental Ice Age archivists. Archivist. Why archivists? Because they hibernate underground for about eight months of the year, and when hibernation ends, those squirrels are hungry.

And just wake up like a zombie crawling out of the ground, you know, and finding anything they could eat in the landscape. That's ancient DNA researcher, Mikkel Winter Peterson. And what an image, right? He didn't work on this paper. But he says squirrels would have eaten really anything, plants, insects, and even the remains of animals bigger than them. So archiving their DNA, if you will. In their waste. In their waste. That's the archiving. Yeah.

And sure enough, you know, they found these groups of plants, but then they also found DNA from woolly mammoths, an extinct form of bison, caribou, an extinct Yukon horse, and then even some birds, all, if you can believe it, in these squirrel droppings. So we can study the DNA of woolly mammoths because of this ancient squirrel poop? I had no idea. You could learn all that from animal droppings. I know.

And funny, you should say that, because in the past, researchers have sometimes dismissed animal excrement because they thought, well, it's only just going to show that animal's DNA, right? But the fact that they learned so much about the environment at this time shows this could be a method for understanding Earth's history. Here's Tyler. So if you're out for a hike and you see, you know, some old poop, you might think that's nothing. But the kind of data you can get is just remarkable with millions and millions of DNA fragments of all these organisms together. that can paint a picture from something that you otherwise would have just thought nothing of passing by. So, Mary Louise, I hope that gives you something to think about on your next hike when you look at the ground or step in it. Who needs mountains? Who needs sparkling streams when we can be looking at squirrel poop?

Totally. And if you're not an outdoor person, maybe you can just stay inside and watch some ice age and come chat with us as a movie club. Wow. Anyways. I'm sure you want to come back on our show. Thanks for being here today. Thanks for being here today. My total pleasure. Anytime. You can hear more of Mary Louise Kelly on Consider This, NPR's afternoon podcast on what the news means for you. And for more science stories, just like this one, follow Shortwave on whatever app you're listening to. This episode was produced by Rachel Carlson and Kai McNamee. It was edited by Rebecca Ramirez, Christopher Entaliata, and William Troop.

Tyler Jones, Check the Facts, Maggie Luthar, and Josephine Nio and I were the audio engineers. I'm Emily Kwong. And I'm Angela Zang. Thanks for listening to Shortwave, the science podcast from NPR.