Denver Had Some Of The Worst Air Quality In The World. Here’s How That’s Affecting Our Brains.

Image created by Alexis Kenyon via Dall-E

This month, with wildfire smoke blanketing the Front Range, Denver and surrounding areas have had some of the worst air quality in the world. And while the air has cleared, even on good days, Denver and the Front Range has some of the worst air quality in the nation — especially when it comes to the type of pollutants that aren’t as visible, like ozone. 

KGNU’s Alexis Kenyon spoke with Jim Robbins, a Montana-based health and science reporter who writes about science and the environment for outlets like the New York Times and Kaiser Health News. In his article, he looks at how, for the first time, researchers are pinpointing evidence about how bad air quality can physically alter a person’s mental health. 

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Interview Transcript:

Jim Robbins: A few years ago, I started writing about air pollution, and looking into ozone. Denver has some of the highest levels of ozone pollution in the country. As I looked into ozone, I realized, ‘Wow, this is, this is a much more serious problem than I thought.’

 They call ozone the invisible pollutant because you can’t see it, smell it, or taste it. People aren’t really aware that it’s there. But it’s something you really should pay attention to, especially children and older adults because it can really tax your respiratory system, your heart, and now we know, your brain. 

There are two particle categories in air pollution that cause physical problems. One is called PM 2.5 and those are fairly large particles that you breathe in. But, what turns out to be the real bad guys in all this are the ultra-fine particles that come from school buses, diesel exhaust, trucks, dust, soot, that kind of thing. Those are the ones that get, not only into your lungs, and your respiratory system but also get into your brain.

The nose has been called the front door of the brain because there’s a direct pipeline that goes from your nose up to the olfactory bulb. This is why when you smell something like bread, baking, or something, you might have quick memories of your mother baking bread or something like that. Well, the reason is the brain directly connects to the olfactory bulb and so when you breathe these particles in through your nose and mouth, it goes right into the brain. These particles carry with them, heavy metals, iron, titanium, and other things that are attached to the pollution. They get into the neurons, and they damage the neurons.

And then what they do is there are several parts of the brain like the hippocampus, the amygdala, and the prefrontal cortex. So let’s take the amygdala. So the amygdala is an almond-shaped part of the brain. It governs your fear response. And so if it’s damaged, or the prefrontal cortex or the hippocampus are damaged by these ultra-fine particles, they can’t carry out their full load of responsibilities. And so this is the theory that these particles damage those parts of the brain. They are not robust any longer and people may, for example, begin to have trouble with anxiety and depression because of this impinging on their function.

Alexis Kenyon: Okay, so to recap, the theory is these ultra-fine particles, when you breathe them in, they’re shot directly to your brain, and they can damage the parts of your brain that determine how you feel about the world. So, for example, with the amygdala, which governs your fear response, you may feel fear differently, which would explain anxiety or a change in your anxiety levels?

Jim Robbins: Exactly. And so there are two theories about how particles damage the brain. One is that they directly damage these areas that I talked about, the amygdala or the prefrontal cortex. And, the prefrontal cortex is really an important organ. It’s about the size of half of an avocado. And it’s on the left side of the brain and they call it the “organ of civilization.” The reason they call it that is that it’s responsible for integrating your conscious thoughts with your emotions. And so if you’re properly regulated, your prefrontal cortex is allowing you to express yourself properly, appropriately, as far as your emotions, how you feel about things, and so on. But if its function is impaired, there are direct impacts from these ultra-fine particles, especially on a neural function. So, you take a whiff of diesel smoke. That goes into your brain and impairs the function of a region like the prefrontal cortex.

The other theory about how the mechanism of this is that it causes inflammation in the brain. And it might not be one or the other. It might be both things. Again, this area has a lot of research enough to say this is real, but the details of it are still being researched and are still being understood.

Alexis Kenyon: How would you say people should weigh the risk of, you know, the mental health boost they get from exercising outside and the physical boost versus the, you know, potential damage of breathing in bad air?

Jim Robbins: That’s a really good question. And I have talked to experts and say they’re not really sure what the trade-offs are. Is not getting exercise better than getting exercise in an environment with ultra-fine particles? I would guess that you might at least lower your exposure by not exercising as much, or exercising indoors. And then there are times of the day, when these levels are lower, maybe early in the morning, before the traffic is out, or after the traffic is out and before it gets too warm, you could get out and do a run.

I would definitely time my exercise according to when pollution levels were the lowest. The other thing would be to not exercise anywhere where there’s a lot of traffic. Get out in the hills. You’re always going to have some exposure but if you can get up above the pollution, that would help. But in Denver itself, or major metropolitan areas along this Front Range, you’re going to have high levels of pollution most of the time, especially in the summer.

Alexis Kenyon: Before I let you go, is there anything that I missed that you want to add or you think people would like to know?

Jim Robbins: I would say the best defense against this kind of thing is to be mindful of what is happening. This is real. Denver is under a lot of pressure to fix this because the EPA has classified the Front Range as in “serious violation” (of air quality standards). It’s one of the highest in the country. And it’s well above standards. And there is a movement out there to say the standards aren’t low enough. In fact, in a lot of the research I’ve done on ozone and pollution, people say these standards are too high. So even though the standards are not being met now, some argue, including the World Health Organization, the standards should be much lower.

Alexis Kenyon: Just to clarify because this could be confusing, by lower standards, you mean lower levels of pollution, lower levels of ozone emissions,

Jim Robbins: Right. I don’t remember the numbers off of my head, but it’s substantial. And so people should become conversant at least in what’s going on with pollutants, and how much at risk they are, especially children and older adults. And there are things that can be done, particularly in reigning in the oil and gas industry and some emissions there.

There are many people looking into this issue these days and seeing it as one of the major factors in childhood development. It has surprised me how little a progressive state like Colorado has given free rein to a lot of the oil and gas industry. People have these things in their backyard, you know? They emit a lot of air pollution. So, people need to get up to speed on what’s going on because it’s a much more serious human health threat than I imagined when I first started writing about air pollution.

Jim Robbins is a freelance journalist based in Helena Montana, who writes about the environment and science for publications like The New York Times, and Kaiser Health News.

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