Q&A on Louisville’s air as city gets another ‘F’ on national pollution scorecard

After news that Louisville’s air just received a failing grade for its high rates of particle and ozone pollution, a UofL Health researcher and nurse practitioner says the news is not surprising and steps can be taken to protect people’s health.

Rachel Keith, a nurse practitioner with UofL’s preventive cardiology clinic and a clinician researcher with the Envirome Institute, said that while Louisville has “had occasions to kind of bounce up a little bit and get better” it’s been in “that F range for a while.” 

During a press conference Thursday, Keith discussed the “State of the Air” report, which the American Lung Association released Wednesday. 

The report showed that Louisvillians spend more than a week every year breathing unhealthy air. In Louisville, “unhealthy days” for ozone pollution number eight per year on average — an increase from the average of five reported in the 2024 report. Ozone pollution can come from a variety of sources including cars, power plants, industrial boilers, refineries, chemical plants and more, according to the U.S. Environment Protection Agency (EPA).

Here’s more of what Keith had to say about the report. This Q&A has been edited for length and clarity. 

Question: Why does Louisville have such poor air quality? 

Answer: Air quality has two main pieces that the American Lung Association looks at. One is gaseous compounds. The one that we tend to do really poorly on is something called ozone, and the other is particulate matter. 

Louisville has really high levels of something called NOx (nitrogen oxides) and we also have some high levels of things called VOCs (volatile organic compounds).Think of these as gasses that readily react in the air when you add sunlight on top of it. They mix into this three-oxygen compound called ozone that’s really bad for health. 

Here in Louisville, we have high sources of those emissions that come from combustion, and particularly the NOx — that can be roadway, that can be industry, that can be different sources of it. We also have this stagnant air that comes with being in the river valley. 

So, we have the stagnation of air, we have high production and we have a weather and air pattern that brings other regions’ air into our area. And all that with our sunlight, especially that we have in summer, leads to really high levels of these compounds and these air pollution factors that can affect health.

Q: What exactly is ozone pollution? 

A: Ozone is a gas. Gas is like air; it’s a light molecule, a light compound. It has three oxygens, and it can be reactive and highly reactive. 

In particular, in Louisville, we have a lot of that really highly reactive ozone, which, as it implies, means that it can interact with lots of things. It can interact with a human and make them unhealthy, but it can also do damage to plants and crops and these other aspects of our environment.

Q: Are there risks for people in their day-to-day lives from this pollution? 

A: I think everyone, when you think of a gas or air, things like this, immediately it goes to the lungs. And there are risks for lung problems. It can trigger asthma, it can lead to asthma. People who have COPD or other breathing conditions — this can contribute to that. 

But I think the lesser known and lesser thought about health conditions are really important too. Long term exposure to these, and even at somewhat low levels — so not like you’re looking outside and see smog — can lead to heart disease, strokes, can affect diabetes. There’s now links of air pollution to autism, Alzheimer’s.

Your whole body is negatively impacted by these compounds. Unfortunately in our city, they’re really high, so it’s going to lead to people having detrimental health problems from the air they breathe. 

Q: Are there any signs and symptoms that people should be on the lookout for? 

A: Those ones that you’ll see are definitely related to respiratory conditions. So they’re asthma, people with COPD. It can be trouble breathing, feeling what we call ‘air hungry,’ — even though you are breathing, you feel like you’re not getting enough — wheezing. 

Most people have very distinct symptoms to their particular condition, and so those are the ones you’re going to see right away. 

What’s harder are those that take 10 to 15 years to really manifest, because you don’t feel your arteries hardening. You don’t realize you’re not getting the blood flow, or the proteins may be changing in your brain. Those are the ones that I think are most scary, because people don’t know they’re happening until it’s too late, and they have a big problem with it.

Q: Is there a way to progress past an F — even to a D or a C? What are things people can start doing to help? 

A: The easy answer is: you have to reduce emissions. That’s the easy answer. That means, if you bring down NOx, if you bring down VOCs, your air quality will change. 

The hard answer is, how? One simple thing I typically think about is: if we say a lot of this comes from combustion and automobiles, Louisville is a big commuter city, and so there are simple choices people can make that could impact our air quality. 

One of them that an individual could do was, if you think of a car pool line or at a drive through restaurant or places like that, whether you choose to idle or turn your car off, makes a huge difference. 

On a policy level, supporting things that can make public transportation easier or more available, things like bike lanes and sidewalks that also could potentially change the dynamic of our transportation in the city are very easy ways to think through a way for us to reduce emissions.

Q: What effect, if any, do disasters have on air pollution? What about the 2024  Givaudan Sense Colour explosion? 

A: All these are going to affect it. 

Wild fires and explosions, industries, controlled burns that sometimes happen — these all impact air quality. In particular, in 2024, we had those emissions blowing down from up north (Canada). That year was absolutely impacted by wildfires. And it also goes to show that those can be in a whole other area, region, country, and our air quality changes with it. 

Q: Does air pollution ever lead to acute problems? 

A: Asthma attacks are a very relevant acute problem, as is an exacerbation of COPD, but it can change your heart rhythms. 

We do think that there’s a potential for those to trigger heart attacks, but the duration you’re exposed and the levels plays into that. It’s not a given, but there are studies that suggest even things like an acute heart attack can occur at these higher pollution levels.