Short Wave - The Pandemic Cut Down Car Traffic. Why Not Air Pollution?

Episode Date: May 28, 2020

An NPR analysis of a key air pollutant showed levels have not changed dramatically since the pandemic curbed car traffic in the U.S. NPR science reporter Rebecca Hersher and NPR climate correspondent Lauren Sommer explain why — and what really makes our air dirty. Here's their story.Email the show at [e-mail] 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

Hey, real quick, if you're new to the show, make sure to subscribe or follow us on your podcast app of choice. That way you get fresh episodes as soon as they're out, first thing every weekday. Ah, the smell of fresh-baked science in the morning. You love it. You're listening to Shortwave from NPR. Maddie Safai here with NPR Climate Correspondent Laurenne. Hey, Lauren. Hey, Maddie. And science reporter Rebecca Hersher.

Hey Maddie. Do you remember March? Yeah, Becky. Of course I do. It was last month. Do you remember what was going on outside in March? Yeah, I mean, I remember looking at it. The outside, I looked at it. And what did you see while you were looking at it? I feel like this is a weird trap, but birds, fresh air? Not a lot of traffic. Bingo. From a shockingly smog-free New Delhi in India.

Fresh air. To unusually clear waters in the canals of Venice. The world is suddenly learning what can happen if humans stop polluting the environment. In fact, if you listen to the news back in the beginning of the pandemic in the U.S., with more of us staying inside and off the roads, you probably heard it was the freshest, cleanest air ever. Cities around the globe are reporting less air pollution. We're also seeing wild animals roam in very unexpected places. Right. Nature is healing, Lauren, as they say, and keep saying.

Yeah. And it is true that traffic plummeted in mid-March. I mean, it dropped around 40%. So you get rid of car traffic, you get clean air. Is that it? Because, like, I don't know if we need a whole episode for that. You too. Yeah, actually, that's it.

That's the whole thing. I'm going to go now. Okay, Becky's kidding. We're science reporters here. We look for data, right, to back up what the headlines say about the world. So we called up our colleagues in the investigations unit at NPR. They're data journalists. and we asked them, was the air really that much cleaner? Can we measure that? And they said, sure, give us a few weeks. They analyzed half a million air pollution measurements from across the country during the pandemic, and they analyzed the five years before that. In a few weeks? They're very good. And that way, they compared the average amount of pollution from this spring to the average amount of air pollution from the previous five years. And just to be clear here, I know you already know this, right?

But we're not talking about carbon dioxide, which is a greenhouse gas that locks in heat, makes the planet warmer. You know, climate change. What we're talking about are pollutants that make smog and soot, which make the air dirtier. Right. Okay. So you measure those pollutants. What's the answer? Becky, did the air get a lot cleaner because of the pandemic?

No. It only got a little bit cleaner. Our analysis found that during the pandemic, a pollutant called ozone only dropped by 15% or less in most parts of the country. And in a lot of places, it barely dropped at all. So today in the show, why the pandemic air isn't as clean as a lot of the headlines suggested and a lot of people hoped. And how scientists are making the most of this time to study where air pollution comes from and how to tackle it. You're listening to Shortwave, the Daily Science podcast from NPR.

So there was definitely one picture, but I remember seeing, a freeway in Los Angeles. arguably the traffic capital of the United States. And there were no cars. It was like empty freeway, clear blue sky, and now you came here on this podcast, and you're taking that all away from me. Well, actually, the air was cleaner in Los Angeles in March. It was the longest stretch of clean air

that had been recorded in decades. And, you know, that's a big deal for L.A. because their air is not great sometimes. There's high levels of ozone, which is a pollutant that's formed by all the stuff that comes out of tailpire. and smokestacks and power plants. What it does is it mixes in the air at ground level. You add some sunlight and you've got ozone.

And it's not good stuff. It exacerbates respiratory and cardiovascular illness. So it makes sense that everybody would be pretty psyched about cleaner air. Yeah. And it seemed like that made sense, right? With all the lockdown and people staying at home. I mean, they started asking the air regulators about that, like Philip Fine of the South Coast Air Quality Management District.

There was a lot of pressure on us to come up with the answer. that everyone wanted to hear, which is that the COVID-19 measures have cleaned the air in Southern California. But here's the thing. It was also really rainy in L.A. during the same time. And rain helps clear out the air. So as the weather has dried out recently, air quality has gotten worse again. I mean, it went back to the unhealthy category, actually. Yeah. Okay. So I guess when you think about there was this 40% reduction in traffic and only a 15 or so decrease in ozone in lots of parts of the country, it's not nothing, right? It's more of a like not much, not a ain't nothing. Yeah, it certainly helped some. But, you know, believe it or not, it sounds kind of strange.

Cars are not L.A.'s biggest source of pollution when it comes to the pollutants that make ozone. And that's actually true in a lot of places in the U.S., which, as Fine told me, that means what's happening now with reducing car traffic just isn't really enough. We've read a lot of newspaper articles over the past couple weeks. that if only we can have people telecommute one day a week across the entire basin, our air quality problems will be solved. And unfortunately, it's not that simple. That's because the big source in L.A. is trucks. And a reason is because there's just a lot of shipping that comes through the ports of L.A. and Long Beach.

And they handle about 30% of the country's shipping container traffic. And that gets moved around on trucks after it comes in. So truck traffic, it didn't decrease as much as the car traffic, So a lot of that pollution was still being emitted. Okay, so trucks are the problem in L.A. Becky, what about other places? Yeah. So other places have other pollution sources, like Pittsburgh.

We looked at Pittsburgh. And ozone only fell by 9% about between mid-March and the end of April. And when I asked atmospheric chemists about this, they were like, the reason is coal. Oh, the coal. Coal that's burned to make electricity primarily, but also coal that's used to make steel. right? The history of Pittsburgh is all about steel. We still have some very active industrial sources near the city. And this geochemist at the University of Pittsburgh, Emily Elliott, says coal is really dirty.

We're in closer proximity to the places that are generating power, the coal-fired power plants in the Ohio River Valley that contribute quite a bit to pollution. Okay, so Pittsburgh has coal, L.A. has trucks. Anything else I should know about? Yeah, Houston has this thing with factories. Oh, right. Rebecca Herscher, we've talked about that on the show before. Indeed, we have. And for those who might not remember, Houston has one of the largest concentrations of petrochemical facilities in the country. So to see how ozone levels have changed there versus other places, that was an interesting question for us. And what we found is that those facilities, they mostly kept operating during the pandemic, actually. In fact, a lot of them, they make the raw materials for masks and gloves, the PPE that hospitals need so desperately right now.

So I'm guessing that ozone levels didn't decrease a lot in Houston. Exactly. Ozone decreased less in Houston than it did in L.A. Okay, so it sounds like industrial pollution versus pollution from our, like, private cars is a big deal. Are scientists looking into that, Becky, like how much industry plays into this? Yeah, they are. And it's possible that the overall air chemistry has also changed when we remove cars from the picture, which is kind of an intriguing idea. Like air pollution is kind of a soup of different chemicals and bits, and that soup is different now.

And there's something even more confusing that happens with that soup, that air chemistry. And this is really strange. So stay with me. This is really strange. So say with me is actually shortwave's tagline. So go on, Laura. You're at home. Well, we mentioned that stuff coming out of tailpipes and other sources is what makes ozone, right?

That stuff is nitrogen oxide. So nitrogen oxides help form ozone. But here's where it gets weird. Under some conditions, you know, in the short term, nitrogen oxides can break down ozone molecules instead of forming them. So some pollutants can break down other pollutants is what you're telling me. Yes. And I called up one environmental engineer that's looking into this. Sonica Ivy at the University of California Riverside. She says with fewer cars, nitrogen oxides are down. But that means they aren't doing the job of suppressing ozone. So ozone goes up. And to get over that weird effect, you actually have to cut pollution a lot more.

What it shows is that the level at which we decreased was not enough to reduce ozone. And so we're just going to have to be more aggressive with our sustainable transportation solutions. Okay, so that's kind of weird. I mean, it means we can be doing the right things for air quality, like driving less. But it's not going to necessarily have the effect you'd want to see, at least not at this level. Yes. And then, you know, on top of all of that, the federal government added another wrinkle to this story. We will now hear from our witness, the Honorable Andrew Wheeler,

administrator of the Environmental Protection Agency. So this is congressional testimony from last week. the head of the EPA was testifying, and the big issue that came up was whether the EPA is doing enough to control air pollution during the pandemic. Why was that such a big issue? Like, isn't it always the EPA's job to enforce air pollution regulations? Yeah, but in late March, when COVID-19 cases were ramping up, the EPA put out this document, and it was addressed to companies that are regulated by the EPA basically said, hey, so we understand

that the pandemic might make it hard to, for example, check how much pollution is coming out of your smokestacks or repair leaks in chemical storage tanks or file those monthly reports that you usually have to that show that you're only releasing the pollution you said you were going to. And this is how the EPA administrator described this guidance document in his testimony. We regulate over 1.1 million facilities across the country. And many of those facilities have been shut down and they do not have the staff on hand to submit their reports to us. So basically the EPA was saying to companies, if they can't comply with pollution regulations because of the pandemic, that's okay.

The EPA probably won't punish them. Because these are extraordinary circumstances, this global pandemic. Exactly. But one thing that makes a lot of people nervous about this policy is, you know, we're in the middle of a respiratory disease outbreak. Right. So some people are like, wait a second. Now the EPA isn't doing everything it can to make sure we're breathing. clean air right now. It's especially in places with a lot of industry. Like Delaware Senator Tom

Carper, he pushed the EPA administrator on this in a pretty blunt way. Will you stop writing rules that make things actually worse, not better? All of our rules make things better, sir. And Mr. The EPA doesn't require companies to tell them if they're not complying with pollution regulations during the pandemic, so it's hard to know if there's extra air pollution and where it's happening. Oh, wow. So they don't even have to say like, hey, we're a not going to be able to comply with this. Yeah, they're not required to. Wow. Okay. All right. So I'm going to be honest, you're bumming me out. Is there anything we can do to fix the pollution soup? And also,

I will not forgive you for calling it soup. Well, science. Let's think of science as the silver lining here. Always do. Okay. This is like a strange natural experiment that is kind of exciting for scientists. Like, when have we ever removed 40% of cars from the road just to see what happens? Now, scientists who study air pollution and where it comes from, they have this whole new set of data that they never would have had before. Sure, but I also think like, you know, this like, what a time to do experiments mentality feels a little weird to me. Like so many people have lost their jobs, 100,000 people, you know, have died in the United States. How can we feel good about anything that comes from that? Yeah, I totally feel the same way. And I actually asked a lot of

the scientists I talked to, that same question. And some of them were like, yeah, it's sad and hard, but data are data and we're excited to have this information that we would never have gotten otherwise. That's kind of the like boilerplate response. Sure. But one scientist, she's actually a statistician who studies air quality. Her name is Jenna Kral. She said something that I hadn't thought about before, which is that some of the biggest leaps forward in our understanding of air pollution historically have come during public health catastrophes. Like if we think back to the DeNora smog or the London fog events. Yeah, maybe it is a silver lining

or maybe it's just an opportunity to help to be smarter, I guess, in the future, to learn what we can so that when we think about how changing the pollution mixture in the future might impact health will be that much smarter. All right, you two. Thank you for all these data. The greatest gift you can give a person. Thanks, Mandy.

This episode was produced by Brent Bachman, edited by Viet Le and fact-checked by Emily Vaughn. And a reminder before we go to make sure and subscribe or follow this podcast, to make sure you get new episodes as soon as they're available, which you want. I'm Maddie Safaiy. Thanks for listening to NPR's Shortwave. There's no getting around it. The coronavirus pandemic has upended everything. And daily decisions made by the White House and Congress

will radically impact the human and economic toll. To keep up with the latest, join us on the NPR Politics Podcast. We'll cut through the noise and let you know what decisions are being made and how they affect you.