Health Wanted: Wildfires

The Episode

Sometimes it may feel like the world is metaphorically on fire, but it’s important to remember that it’s also often literally on fire. This week on Health Wanted, we’re taking a look at the increasing impact of wildfires on both the environment and your personal health.

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The Listener Questions

Is Parkinson's disease caused by environmental factors like pesticides and pollution?

Parkinson’s disease is caused by a loss of nerve cells in the part of the brain called the substantia nigra. This part of your brain controls your body’s movements and influences your brain’s chemistry through the production of dopamine, which causes progressively worse tremors, rigidity, slow movement, and balance issues.

There is no single known underlying cause of Parkinson’s disease, and it progresses differently for each person, with symptoms appearing at varying speeds and intensity. 

Scientific knowledge is constantly changing as new evidence emerges. Prior to the 1980s, Parkinson’s was mostly viewed as a textbook example of an environmentally caused disease. That was until the Contursi kindred were discovered. Of the 400 identified members of this extended family, who all descend from a single couple, 61 are known to have Parkinson’s. This was the first description of inherited Parkinson’s, and it led to the discovery of specific gene mutations linked to the disease. 

However, genes only contribute to about 10 to 15% of all Parkinson’s disease cases, which means that it is likely caused by a complex interplay of genetic and environmental factors. The evidence linking environmental factors alone to Parkson’s disease is inconsistent and subject to bias.

Our behaviors and environment can cause changes that affect the way our genes work, a relationship known as epigenetics. Think of DNA as a set of instructions and the epigenome as directions that tell you which parts to read, ignore, or edit. These directions can be passed onto the next generation but do not affect the underlying set of instructions. For example, epigenetics can explain why, despite sharing the same DNA, identical twins are not completely identical.

Environmental factors can also influence how the instructions are read or which genes are turned on or off. There is a growing body of research that indicates epigenetic factors have a huge impact on Parkinson’s disease. 

So your thinking wasn’t entirely wrong. Yes, there is a genetic component to Parkinson's disease. But, there is also an equally important environmental component. When studied together, epigenetics may serve as a missing link between Parkinson’s disease risk factors and the development of the disease. 

Is my car's HVAC system filtering out air pollution while I sit in traffic?

Cars and trucks are responsible for about one-third of all air pollution in the country. This pollution is caused by exhaust and microplastics from tires wearing on the roads. Research has shown that exposure to traffic-derived air pollution is associated with a wide range of adverse health effects, ranging from respiratory diseases to cancer, cognitive function declines, coronary heart disease, diabetes, and even preterm birth. 

When you’re on the road, the concentration of traffic-derived air pollution is typically several times higher than the surrounding environment. In fact, even compared to the side of the road, air pollution concentrations at the middle of the road are higher. 

Our cars take in emissions from surrounding vehicles through open windows and air vents. One study found that the levels of some pollutants can be as much as nine to 12 times higher inside vehicles than alongside the road. 

Sitting in traffic only makes things worse. Intersections with traffic signals have up to 29 times higher concentrations of particulate matter than open roads. And while you are stuck in heavy traffic, the pollution inside cars can be 40% higher than when you’re moving. 

Your car has an HVAC system, and you should change the filter out regularly, roughly every 15,000 to 20,000 miles. Research on the efficacy of air filters has shown that, regardless of price point, they significantly reduce the levels of traffic-derived air pollution. 

Of course, avoiding traffic altogether would reduce the amount of pollution you are exposed to. But when that’s not an option, close your windows, keep some distance from the vehicle in front of you, and put your air on recirculate. 

Catch all the listener questions and Laurel’s answers on the full episode of Health Wanted by:

• Streaming at wabe.org or the WABE app
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