On our last podcast, Mad in the Family covered the effect of climate change and extreme weather events on children’s and mothers’ mental health. This one continues the conversation on environmental links to emotional distress: emerging research showing that pollution in the air and water can affect our minds and emotions, and that children are especially vulnerable, both while they are young and later in life.
Kristina Marusic is a Pittsburgh-based investigative reporter for Environmental Health News, an award-winning, non-partisan organization dedicated to driving science into public discussion and policy. Last fall, EHN collaborated with Allegheny Front on a five-part series, “Pollution’s Mental Toll: How Air, Water, and Climate Pollution Shape Our Mental Health.” They found that residents throughout western Pennsylvania were likely suffering changes to their brains due to pollution in the surrounding environment, even at levels below federal limits.
Prior to joining EHN in 2018, Kristina covered issues related to environmental and social justice as a freelancer for a wide range of digital media outlets including The Washington Post, Slate, Vice, Women’s Health, and MTV News, among others. Her reporting on environmental health for Public Source won first place in the Keystone Society of Professional Journalists’ Spotlight contest in 2017. Kristina holds an MFA in Non-Fiction Writing from the University of San Francisco and a bachelor’s degree in Creative Writing from Hofstra University. She is the co-founder and chair of the Pittsburgh chapter of the Association of LGBT Journalists.
The following transcript has been edited for length and clarity. Listen to the audio of the interview here:
Miranda Spencer: What emerging scientific research or events led EHN to start covering this connection between air and water pollution and mental health?
Kristina Marusic: I was working on a big collaborative project involving lots of media outlets that were covering mental health broadly. That made me wonder what sort of connections existed between environmental health and mental health. And when I started looking into it, I found that this is a relatively new area of study, but that the few studies that do exist were finding really compelling evidence that pollution impacts mental health in some really important ways.
As you mentioned, I wasn’t surprised to learn that being worried about pollution or climate change can contribute to anxiety or depression. But I was very surprised to learn that pollution can also cause physical changes to our brains that can impact our mental health.
Spencer: Let’s talk about air pollution. What were some of the main findings from your series last fall on the effects on emissions from fossil fuel production and other industries on mental health, especially in children?
Marusic: I talked to the authors of three recent studies on air pollution and mental health. The first study out of the U.K. was really unique because it followed kids who’d been exposed to air pollution for 20 years, which is quite a long study. They found that the more air pollution people were exposed to as children, the more likely they were to develop symptoms of “mental illness” when they turned 18, which is when symptoms tend to first show up for lots of people.
And they did a good job of controlling for other factors by adjusting their findings to account for things like family psychiatric history, socioeconomic deprivation, social disconnection, and dangerousness in people’s neighborhoods. And that study was also unique because it looked at symptoms of mental illness rather than specific diagnoses. So, they used surveys to look at things like anxiety, depression, eating disorders, substance use, post-traumatic stress.
And Aaron Rubin—the lead author of that study who I talked to—said something I thought was so smart and so interesting. He said they did that because the idea that there’s a specific disorder people get, with an on or off switch, is really outdated. Mental illness is not binary. We’re not simply either depressed or not depressed. But we all walk around with symptoms of mental distress that we find more or less burdensome depending on what’s going on in our lives and our ability to regulate that distress.
That was the newest study. But it was also relatively small. They only looked at about 2,030 people for that study. I also wanted to look at some of the bigger studies that exist. The second study I looked at was published in 2019 and it looked at mental health data from 151 million people in the United States and 1.4 million people in Denmark. That study found that long periods of increased air pollution in urban areas were linked to a 16% increase in cases of bipolar disorder and a 6% increase in depression diagnosis. This one was looking at formal diagnoses from a physician.
Spencer: So, mood symptoms?
Marusic: Right. Those researchers had more detailed data for the Denmark group than the American group. The link between air pollution and mental illness for that group was even stronger. Among those 1.4 million people in Denmark, air pollution exposure was linked to a 31% increase in bipolar disorder, a 104% increase in schizophrenia, a 210% increase in personality disorder and a 68% increase in major depression. Those are significant increases with exposure to air pollution.
Spencer: And the third study?
Marusic: Those first two studies both looked at the long-term effects of air pollution on mental health. I also spoke with the author of the first study to ever look at the mental health effects of short-term exposure to air pollution in children. Rather than following kids who were exposed or adults who were exposed over a long period of time, they looked at five years of emergency room data for more than 6,800 kids and teens who visited Cincinnati Children’s Hospital for psychiatric distress. That included things like anxiety, depression, bipolar disorder, suicidality, personality disorders and schizophrenia.
They found that kids who were exposed to high amounts of air pollution or higher amounts of air pollution—not necessarily exorbitant amounts—were significantly more likely to end up in the emergency room for a mental health problem a few days later than children with lower exposures.
Spencer: It sounds like there’s something neurotoxic going on here.
Marusic: Yeah. Scientists are still trying to figure out exactly what happens in brains that are exposed to air pollution that impacts our mental health, but a lot of researchers think it’s related to the inflammation that air pollution causes. Chronic inflammation in the brain can damage neurons that are involved in our autonomic nervous system, the way regulatory responses can impact our mental health.
In animal studies, they’ve found that exposure to air pollution creates persistent inflammation in the animal’s brain and that can cause symptoms that mimic depression or bipolar disease.
Spencer: I gathered there was also a disparate impact found on communities of color and low-income communities?
Marusic: That’s true. We know that communities of color and low-income communities tend to have worse air pollution in general overall. They’re just more likely to have those exposures. But in that study that looked at kids who went to the emergency room in Cincinnati, they also looked at the overlapping effects of air pollution exposure and poverty. They found that kids from neighborhoods experiencing high levels of poverty were most likely to experience a mental illness crisis following spikes in air pollution.
The author I spoke with said that could be because poverty and crime cause stress, which also causes inflammation in our bodies. He hypothesized that that could be overlapping with the inflammation caused by air pollution to worsen the effects.
Spencer: That makes sense. A few months ago, your colleague, Grace van Deelen reported on scientific findings that ground-level ozone can negatively affect the mental health of teenagers. What is ozone, and how does it seem to affect young people’s brains and behavior?
Marusic: Ozone is a chemical byproduct that gets released when certain pollutants are exposed to sunlight. Those pollutants come from things like car exhaust, power plants, and industrial manufacturing. But they can also come from the fumes that are released from paints, and solvents, and glues. And in the study that Grace wrote about, researchers at the University of Denver and Stanford University looked at mental health symptoms in 213 adolescents who were between the ages of nine and 13 in communities with various levels of ozone pollution.
They found that the kids with higher levels of ozone exposure were more likely to have an increase in depressive symptoms over a four-year period. The symptoms they looked at were things like feeling sad or tearful, withdrawing socially, or losing interest in their daily activities. This is pretty significant because three out of every eight Americans live in counties with ozone levels that are rated F on a report-card type of scale by the American Lung Association.
Those are places with a high number of unhealthy ozone days. Right now, cities in the west and southwest have the highest levels of ozone pollution, which is likely being driven in part by wildfires that are caused by climate change.
Spencer: Doubling back a little bit about the kids’ ER visits, I recall that you wrote that the pollution levels were within federal limits, but they were still causing effects.
Marusic: That’s right. In that particular study, all of the spikes in air pollution they looked at were still below federal air pollution thresholds. None of them actually broke clean air laws. But they still saw this effect of kids that were exposed to these spikes in air pollution being more likely to end up in the ER with symptoms of mental illness.
The author I talked to also pointed out that that study probably represents the tip of the iceberg, because it only captured symptoms severe enough to prompt an emergency room visit, right? It didn’t capture anyone who had a milder increase in their anxiety or depression, but not severe enough to prompt their parents to take them into the hospital. It’s part of this growing body of research in the last couple of years indicating that air pollution is really harmful to human health in various ways at levels that are well below current legal limits.
Spencer: Let’s look at water pollution—specifically lead. I believe there is no level of lead in drinking water that health agencies consider safe. How does lead and other water pollution affect kids’ mental health?
Marusic: Scientists are a lot clearer on exactly how lead impacts the brain than they are about air pollution because they’ve been studying it for a lot longer at this point. Lead exposure impacts a protein receptor in the brain that’s known as the NMDA receptor. That stands for N-methyldextroaspartic acid receptor. The NMDA receptor is critically important for brain development, learning, and cognitive function. But improper functioning of that receptor is also seen in the brains of people with certain mental illnesses. In particular, schizophrenia tends to involve dysfunction of the NMDA receptor.
Spencer: Anything that affects a brain chemical process obviously is going to have some kind of effect on us. So, that makes sense.
Marusic: Right. It’s really interesting how [the researcher] explained this. That NMDA receptor influences the development of inhibitory neurons that help keep the brain balanced. And when it’s damaged by lead exposure, it doesn’t create enough of those.
He said that in a healthy brain, you have excitatory and inhibitory neurons in kind of equal numbers to keep things balanced. If that’s interrupted, and you have too many excitatory neurons, and not enough inhibitory neurons, then the balance is off, and that can manifest as mental illness.
Spencer: I’ve heard that lead in water or lead that kids intake can lead to aggression, learning difficulties, and so on. That’s very well documented.
Marusic: That’s right. A lot of the early research on lead exposure in kids focused on cognitive ability and learning. Some of the recent research has started following kids who were exposed to lead for longer periods of time. They’re finding now that being exposed to lead as a kid can actually impact your mental health in middle age in ways that might not even show up until much later in life.
Spencer: Very interesting. There’s a role for environmental pollution in triggering mental health problems. But it often happens in the larger context. Could you talk about that bigger picture a little more?
Marusic: I think the kind of big, important takeaway is that communities that have high levels of childhood lead exposure are also likely to experience other issues that can disproportionately impact mental health. That can include things like poverty, racism, violence, and also other harmful environmental exposures like air pollution. If you’re in a community with lead in the water, it’s also likely that you’re experiencing higher levels of air pollution.
Research has shown that regardless of income level in the United States, Black children are two-to-three times as likely as White and Hispanic children to experience lead poisoning. And that is a lingering effect of racist practices like redlining, which restricted Black communities to neighborhoods that were considered less desirable by their White neighbors and a clear result of environmental injustice. Similarly, research has shown that Black Americans are exposed to more air pollution than any of their other counterparts regardless of income level. That, again, is kind of a lingering effect of these systemic inequalities.
Spencer: Sounds like a perfect storm. These systemic problems would seem to require government action at some level. What can parents and families do to protect their kids’ brains and bodies from these pollutants, aside from moving, if they can?
Marusic: That’s an important question. I would say that one thing people can do is do what they can to help move along some of those regulatory and government-level changes that we really need to protect everyone. One way to do that is to reach out to your local, state and federal lawmakers to tell them that these issues are important to you and urge them to enact policies that promote clean air and safe drinking water and letting them know that that’s important not only for our physical health but also to protect our mental health.
Another good way to do that is following advocacy groups that do work related to clean air and clean water, especially that are local to you. If you follow those groups on social media, it makes it easier to stay in the loop about new proposed laws, so that you can take action when it’s most important.
As part of the series, we also included a page of resources about taking care of your mental health and getting involved in advocacy related to clean air and water. But at a more individual level, families can consider buying indoor/outdoor air monitors. There are some that are made for home use that have gotten cheaper and more accurate in the last couple of years; Purple air monitors are one brand that’s pretty widely available. Avoid spending a lot of time outdoors, or doing strenuous exercise outdoors, if you’re having a bad air day in your local area.
Indoor air pollution is also a problem. Americans spend 90% of their time indoors. Unfortunately, when there’s air pollution outdoors, it can get trapped in our homes too. People can consider buying an air filter for inside the house. Those can be expensive, but there’s a way to do a cheaper DIY version by attaching a HIPAA filter to a box fan and we can do that for under 40 bucks. There are instructions available for how to do that online and that can go a really long way to help clean your indoor air.
In terms of water, you can use a good water filter that removes lead—basic Brita filters or other kinds of widely available water filters. Mostly all are good at getting lead out. But there’s another filter that removes a lot of additional contaminants called the Zero filter that’s one of the better ones available for residential use.
Most states and cities have lead-safe home programs that can help you test for lead paint and remove it from your house safely if it turns out you have lead paint in your home.
Spencer: Should people who live in polluted areas have their kids’ blood tested to find lead, to get ahead of it to understand what the exposures are, or is the damage already done?
Marusic: When it comes to lead, most U.S. cities require some sort of lead testing for toddlers. I think even outside of cities, most pediatricians take a look at that in the first couple of years of a kid’s life. If your pediatrician is not looking at blood lead levels, it’s definitely a good idea to ask them between ages one and three when you’re having blood work done anyway. Just ask them to do a lead screening.
Spencer: Could you tell us quickly about the community-based mental healthcare models being developed in the Pittsburgh area?
Marusic: Especially after the pandemic, we’ve seen a number of community groups form. Some of them are based on a group-therapy model and some are more just for connection and solidarity, and being able to talk about concerns related to some of these issues, which can go a long way to making people feel less alienated and more empowered to figure out how to take action.
Spencer: Can you think of any other resources families might look to, to get help with pollution issues that can affect their kids’ mental health?
Marusic: It’s important to note all of these studies sound a little scary. But when it comes to individual exposures, the changes were all fairly moderate. Where this becomes a significant issue is when you’re looking at a whole population exposed to air pollution.
The change in one person being exposed to air pollution is not going to make someone who is perfectly healthy suddenly have extreme mental illness. It’s more about the fact that if we’re exposing millions of kids to air pollution, then the cumulative impact becomes significant. That’s something we should be worried about as a society, making sure we have regulations in place in the United States that keep everyone safe all at once, so we’re not putting the burden on individual parents, right? To buy the right filter, and carefully monitor the air, and have to be so, so vigilant about trying to protect their kids.
Spencer: Has any positive change happened since these articles came out?
Marusic: Yeah. A big part of my series was focused on Pittsburgh, which is where I live. The air quality is exceptionally bad here, particularly due to industrial polluters. We have some big legacy industries here that tend to pretty flagrantly violate our Clean Air laws. After the series came out, I heard from a lot of residents who were concerned about impacts to their mental health and wanted to know what they could do to take action. We definitely saw a lot of people reaching out to some of our key lawmakers here in the region to tell them about the links between air pollution and mental health, and “Make sure that they know that this is a concern and this is on people’s radar.”
Those things, changing laws, tend to take time. These things can take years. But thanks to years of this kind of advocacy work here, we’ve seen our local health department—which oversees air quality in the area—step up with its enforcement of clean air regulations in recent months and issue some really big fines to some of those big industrial polluters, which feels like progress.
Spencer: Are you working on any new stories about the links between environmental pollution and child or adult mental health?
Marusic: I’m always keeping an eye out for new studies on this and I’m hoping to do a follow-up story on the series sometime in the fall. But I’m also always open to story ideas. If any of your listeners have them, I’d be happy to hear from them.
- “Pollution’s Mental Toll: How Air, Water, and Climate Pollution Shape Our Mental Health” (five-part series)
- “The Emerging Field of Pollution and Mental Health Research”
- “Pollution and Our Mental Health: A Guide to the Emerging Science on How Air and Water Pollution Impact Our Brains”
- “Ozone Linked to Depression in Adolescents”
- “Our View: It’s Time to Recognize, Research, and Remove Environmental Causes of Mental Illness”
MIA Reports are supported, in part, by a grant from the Open Society Foundations