When Should I Worry About...

PODCAST: How Does Air Pollution Affect Lung Health?

Sep. 20, 2022

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You're not alone if the planet's health is what's top-of-mind when thinking about air pollution. But have you ever considered how it affects your own health? It's invisible, but air pollution is all around us — containing particulate matter small enough to be inhaled deep into the lungs.

In this episode, we unpack what long-term air pollution exposure can mean for our health down the line.

Episode details

Hosts: Zach Moore, Katie McCallum (interviewer)

Expert: Dr. Eric Bernicker, Thoracic Medical Oncologist

Notable topics covered:

  • The link between air pollution exposure, lung cancer risk and other lung issues
  • The science of how air pollution affects the lungs
  • How people with underlying lung issues are even more susceptible
  • Whether all types of air pollution (car exhaust, factory smoke, etc.) are equally harmful
  • The correlation between length of air pollution exposure and a person's risk
  • Whether lung cancer screening should be expanded to never-smokers
  • The way forward, including actionable steps you can take to reduce your risk


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Interview Transcript

KATIE: I'm here with Dr. Eric Bernicker, oncologist who specializes in lung cancer at Houston Methodist. Thanks for joining us today, Dr. Bernicker.


DR. BERNICKER: Glad to be here. Thanks for having me.


KATIE: So, we've got you here today to talk about air pollution and how it can affect our lung health. And, to be honest, this might seem kind of odd given that I live in Houston — the fourth largest city in the U.S. — a city with tons of people, manufacturing plants all around the city. But this isn't really a topic I had considered — as far as my personal risk and my lung health — given I live in a city like this. And I feel like I'm probably not alone? And I was struck listening to something you were speaking about recently where you mentioned that lung cancer is on the rise in never-smokers and how air pollution might be a contributor to this. And, so, can you explain to us a little bit more — what we know and what we don't know about how air quality affects lung health?


DR. BERNICKER: I think that there are a number of issues here. There's no question that one of the problems, so to speak, of air pollution is you're right, I mean, for the most part, it's invisible. It doesn't seem like an immediate risk, and it's not on people's radar. We still know that the majority of lung cancers are clearly related to tobacco, but lung cancer remains the leading cancer killer by far and away — more than almost any other type of malignancy. It's the leading cancer killer of women, and it remains a huge public health problem — not just in the United States, but in the developing world, as well. So, the estimates now, between 80 to 85% of lung cancers are probably related to tobacco or, say, occupational exposures. There are some other environmental exposures, like radon, but that tends to be like in basements or in caves in Colorado. And so there has been some supposition that air pollution is a factor for a number of health issues, including lung cancer. And I think that we've known it for a while, but, clearly, there remains significant emerging data that particulate matter in air pollution — which comes from — mostly — burning fossil fuels, it's not just that if you live down the street from a refinery, although that's an issue, but car exhaust, truck exhaust — it remains a huge issue. And it’s not an issue that's solely related to a narrow geography — since, you know, once it gets expelled out into the air, it's there. So there have been a number of epidemiological studies that are clearly indicating, really strongly, that it increases the risk for not just lung cancer, by the way, but probably a number of other cancers — other upper digestive tract cancers, there might even be some role in breast cancer. So, it really behooves us to better understand the mechanism here. And then we need to continue to work on air quality and making, you know, a more healthy environment for everyone.


KATIE:You kind of mentioned this, the particulate matter and smog and things like that. Do we know what, in particular, the particulate matter is doing inside of our lungs and in our body to cause cancer or other issues?


DR. BERNICKER: There's a lot of hypotheses. But the theory is that, over time, as these small particulate matters of smog is inhaled it sets off chronic inflammatory irritation in the lung that probably decreases immune surveillance — meaning premalignant cells are not detected. And that inflammation can also aggravate and cause cancer. And so there needs to be continued work on that, but that's the supposition — that it clearly is not necessarily only, for example, related to smokers who are exposed to air pollution. Clearly, there is data that people who've never smoked are getting an increased risk of lung cancer compared to people who live in areas with lower degrees of pollution. [There has] been some data out of Asia that indicates that as well. I think we're getting a better handle on what the health risks here are.


KATIE:You mentioned that it can cause chronic inflammation. Do we have an understanding of the biology around that and kind of the state it puts someone in?


DR. BERNICKER: I think often what happens is two-fold. I mean, in the same way that smokers, of course, you know, when they're inhaling, there are a number of lovely chemicals in in tobacco. So, it's not just nicotine, right? It's a lot of the other things that go along with it. And, so, as the airway gets irritated, the lining of the bronchus — as it gets chronically stimulated — the immune system comes in, there's irritation, sometimes the surface starts to change, the cellular morphology changes into cells that aren't quite normal. And so a pathologist looking at it would know that's not a normal cell. And then, of course, we think what happens over time [is that] those inflamed cells then begin to grow abnormally and then they start to acquire mutations, right? So as their DNA mutates, that's when the cow gets out of the barn. And now you've got an early lung cancer that can now start growing autonomously. And that's what leads to problems down the line.


KATIE:I would imagine that someone who has, perhaps, a lung condition already — an underlying lung condition like asthma, maybe COPD or it sounds like maybe someone who has an immune disorder — might be even more at risk for experiencing this damage?


DR. BERNICKER: It's true. And we also know that, for example, people who already have lung cancer and who get their treatment in an area with worse air quality have worse outcomes. So, I think that, synergistically, it makes their lung function worse — puts more stress on the heart. I mean, there are a variety of health issues that cascade from poor air quality, there's no question.


KATIE: And when we talk about particulate matter, I know there's sizes to consider. With air pollution, is all of it of such a size that it can be inhaled very deep into the lungs?


DR. BERNICKER: If you start reading a lot of the data, they'll talk about PM 2.5. And those tend to be the size that can get the farthest into the lung and wedge. And, you know, our lungs are not really designed to scavenge and get rid of that size and those particulate things — so the body can't handle it. It’s not an acute event, right? So, it's not like a firefighter [with] a smoke inhalation injury — they can have a whole bunch of issues with that. The point is that this is a chronic, ongoing exposure over time that builds and leads to damage and triggers ongoing issues with the development of cancer.


KATIE: Do we know about how long? Let's say, for instance, if I live in Houston for 20 years, I'm worse off than ten? Or is there any indication of the timeline where someone needs to start worrying or anything like that?

DR. BERNICKER: So, I think there are two issues. I think, adults, you're right, this is not something that happens immediately overnight. There have been some studies that have looked at people over a ten- or 15-year period. Clearly, at the end of this 15-year data, at that point, there is an increase in risk. Children are obviously much more adversely affected because they have little bodies and littler lungs. We've known for a while that children who live in areas of the city where there's, you know, by freeways or where there's a lot more car exhaust, have much worse asthma rates, they have more asthma exacerbations. So, again, that's not cancer directly. But the point is that they are much more susceptible to pulmonary side effects of being exposed to air pollution.


[Music plays to signal a brief interjection in the interview]


ZACH:After hearing Dr. Bernicker talk about how air pollution can affect the lungs, we wondered whether the same is true for other types of particulate matter — like Saharan dust or the plumes of wildfire smoke that sometimes hang over our city. Similar to air pollution, both contain fine particles small enough to irritate the lungs. Temporary exposures we face from time to time can cause respiratory issues like coughing, wheezing and difficulty breathing — especially for people who suffer from airway or lung issues like asthma or COPD. As for whether Saharan dust and wildfire smoke may also increase a person's risk of cancer, Dr. Bernicker says that's harder to answer. For starters, these are transient occurrences, typically clearing up in days or sometimes weeks. Pollution, on the other hand, is always hanging in the air above a city with poor air quality. It's also full of known carcinogens, which is the term used for substances capable of causing cancer. Studies haven't yet looked at how temporary exposure to either wildfire smoke or Saharan dust over multiple years may affect a person's long-term health.


[Music ends to signal return to the interview]


KATIE:When we talk about the air pollution that is leading to perhaps the rise of lung cancer in never-smokers, is it as simple as car exhaust? So, living in a city with tons of cars, you know, in Texas, there's millions and millions and millions of registered vehicles. Is it living in the same rural area as a plant, like a plastic manufacturing facility? Is it a combination of both? Do we know really the biggest geographical areas where people should be concerned?


DR. BERNICKER:So, a couple of things. I think that it depends on where in the world you're looking at that. So, there are parts of the world where a lot of people, for example, cook over indoor flames with wood. So, they're getting smoke or biofuel fumes in their home. Very bad. People sometimes don't have options, but that's an issue. I do think that when you're looking in America, I think the bigger issue does remain both street exhaust — so in high volume, high traffic areas — and then, yes, close to industrial plants. I'm not trying to paint all of those chemical plants as bad. That's not what we're saying. But people do have to be aware that certainly, by the way, if you live by a plant and you smoke, you should stop smoking. By the way, you should stop smoking as best you can wherever you live. But they combine. So, if you live in a place where you know there's poor air quality, smoking on top of that is a double whammy that no one needs. And, so, I just think we need to educate people and they need to be able to take some of those matters into their consideration as they're deciding their lifestyle choices. And then climate policy and health policy need to catch up and help to safeguard the quality of the air we breathe.


KATIE:The geographical aspect reminds me of when the COVID-19 pandemic first started, and we were all in lockdown. Because my watch, every day, sends me a notification — or every now and then will send me a notification — about the air quality. And I remember, you know, we were all in lockdown. Nobody was on the streets. And the air quality — the little bar — was green for way more days than I've ever seen it before. So, you know, back to policy, it does seem like something as simple — I'm not saying we can all stop driving, that's not realistic — but we did see that almost had an immediate effect, I think. Would you agree?


DR. BERNICKER: Absolutely. And, so, there was no question there was such a drop in commuting. Now, that doesn't mean, as you said, that we need to get every single person on a bike — although I'm sure there are people who think that would be a great idea. I do think that moving forward consideration has to be given to increase public transportation, to increase the utilization of electric vehicles for transportation that don't have the same exhaust. Now, that's not going to be immediate, but the way forward, in terms of interventions that can lead to decreased car exhaust and truck exhaust, would make a huge difference over time in health. There's no question.


[Music begins]

KATIE:Could the rise of lung cancer in never-smokers change how we think about lung cancer screening? Up next after the break.


[Commercial break]


KATIE: We're back with Dr. Bernicker. My question is: If air quality is poor in someone's area, what can they do to protect their health?


[Sound effect signals the return to the interview]


DR. BERNICKER: There are certain health conditions where, yes, if you diet or you exercise…there are things immediately in your control, that you can make changes and really impact your health. But from a realistic standpoint, you can't snap your fingers and change what's going on outside. But, that being said, for example, I don't know that if you're jogging under a freeway or, by the way, running around Rice University at eight in the morning with massive lines of traffic up and down, you know, the street all idling with pollution — I think you can really maybe think that maybe is not where you want to jog. I think the bigger issue is that people need to be aware. And if people are in communities where they know they have poor air quality, they need to then get involved with their local politicians because they need to support endeavors that will keep clean air and clean water on the minds of their elected leaders. It sounds like this is some green fantasy. I get that. But there are real health consequences. This is not some utopian hope. This is stuff that is leading to shortened lifespan and illness. And, so, I think that it's not wrong to be aware and to let representatives know that they need to support certain stringent air quality guidelines to safeguard the health of themselves and their children. Sure, does this dovetail to some extent with climate change and the push to...start working more on renewables and to try to decrease fossil fuel utilization? Yes, they do go hand in hand. But at the end of the day, the goal here is health and decreasing the cancer burden and decreasing the hits that people with underlying cardiopulmonary, you know, chronic illness have when they live in an area with poor air quality.


KATIE:Yeah, I think that's great. Do you think — especially the increase of lung cancer in never-smokers — do we think that another way to keep tabs on that in these never-smoker, healthier individuals is to change the lung cancer screening guidelines? Or is that going to be too general? [Meaning] we can't all be screened for lung cancer. Where do we stand on that?


DR. BERNICKER:So, this is a...heated area of discussion. We know, for example, that smokers of a certain age with a certain number of years of smoking, we know they have a benefit from getting CT lung cancer screening. Because — of course, we never want to find lung cancer — when we find it, we want to find it early…when surgery will have a high chance of cure. Lung cancer screening in smokers, unfortunately, in this country has been slow to be adopted. And our hope from the thoracic oncology community is that expands in that population. Now, your question is a good one, which is, you know, if you're a never-smoker and you're triathlon-ing and having kale smoothies — you're doing a lot what you should be doing for your health. And I don't want to overstate it, but there are those folks who are getting lung cancer. So, there is ongoing debate of how we can identify — not just everyone — but how can we identify folks who are never-smokers, possibly who have lived in a particular area where we know that the air quality has been poor, and can we prove that screening in that population will improve survival? And those studies need to be done and will be done, because I think there's no question —there's not, you know, there's not a good blood test. There's not like a PSA for prostate cancer for lung cancer. So, the way we find it is either people have symptoms and then they end up seeing a medical oncologist like me, or we find it with, you know, screening. We've got to do a better job at finding lung cancer in never-smokers. There's no question.


KATIE: Yeah. In the meantime, for people looking for another thing to do to decrease their risk and protect their lung health, do you think masks — our new lifestyle of wearing masks — could be helpful at all in this? So, should people be trying to wear masks if they're just walking around? Probably not while they're exercising outdoors, but can masks be…is this another sort of silver lining to masks we can all cling to? Or is that too wishful thinking?

DR. BERNICKER: You know, you would like to use any excuse to get people to wear masks a little more. We can see how that's been going. And look, we all understand the frustration. I think some of these higher-grade masks probably do filter out, you know, particulate matter. But the bottom line is it's not…I have doubts that that's going to be easily adopted — because, remember, it's about chronic exposure, right? So, while we all want the pandemic to be over — and please…let it be over sooner rather than later — I do think there's clear mask exhaustion, and that's for an acute infectious issue. I think to get people to wear masks, especially when you're jogging outside around Rice — you'll notice no one's wearing a mask when they're out in 90-degree weather jogging — I think that's not going to be the answer. I think the answer is going to be a combination of working together to keep air quality standards high, and then we've got to move to alternative energy sources to try to cut down just on the amount of pollution that's being produced. You know, when you talk about climate change and — in this case, pollution — there's this…also heated debate — everything's a heated debate these days — you know, you don't want to be too complacent, but you don't want to overwhelm people. Because, like I said, I mean, if you're talking about heart disease, someone could avoid having a bacon double cheeseburger on the way home — not shaming people who eat bacon double cheeseburgers, but you know what I'm saying.


KATIE: I know what you mean, yeah.


DR. BERNICKER: You know you could eat better or maybe people can get off the couch more. But when you talk about carbon in the atmosphere or, you know, these particulate things that are floating that people can't see, you don't want people either… I won't…despair is… climate, it's appropriate here, but people sometimes tune out, “Well, I can't do anything about that.” So, the point is that we can modify this, and we can tackle two problems: air pollution and lung cancer and just climate change in general by focusing on making changes in how we get our energy.


KATIE:Yeah, it's a matter of health.


DR. BERNICKER: That's right.


KATIE:And I think that awareness, too, will help people sort of maybe get behind it a bit more than when it's just a big problem we need to solve as a community for the Earth. I think it's harder sometimes to find like a concrete example. But here, you know, as you've mentioned, what we're seeing is affecting people right here in front of us.

DR. BERNICKER:That's right. That's right.


KATIE:Well, thank you so much for being with us today.

DR. BERNICKER:Really enjoyed it. Thanks for having me. I appreciate it.


[Sound effect signals the end of the interview]

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