How Utah Wildfire Smoke and Air Pollution May Increase Stroke Risk
Stroke Awareness Month Highlights Hidden Danger in Dirty Air
How Utah Wildfire Smoke and Air Pollution May Increase Stroke Risk
Stroke Awareness Month Highlights Hidden Danger in Dirty Air
Utah’s wildfire smoke and summer inversions may do more than irritate your lungs; they may also increase stroke risk. During Stroke Awareness Month, University of Utah Health experts explain how air pollution affects the brain, who faces the greatest risk, and what Utahns can do to protect themselves during poor air quality days.
Utah is heading into summer under severe drought conditions, and experts warn that wildfire season could be intense this year.
Along the Wasatch Front, wildfire smoke combined with summer inversions create dangerous air quality conditions for millions of Utahns. While people associate poor air quality with breathing problems, doctors say polluted air may increase the risk of stroke.
During Stroke Awareness Month, experts at the University of Utah want to spread the word about the connection between air pollution and brain health.
“People say, ‘It causes or worsens my asthma, worsens my breathing,’ but cardiovascular outcomes are at least as big a danger,” said Lee Chung, MD, a stroke neurologist in the University of Utah Department of Neurology. “And almost half of pollution-related cardiovascular risk is stroke.”
What Is PM2.5 and Why Is It Dangerous?
One of the biggest pollution concerns is PM2.5: tiny particles (less than 2.5 microns across) from wildfire smoke, vehicle exhaust, industrial emissions, and other combustion sources.
These particles are small enough to enter the lungs and bloodstream, where they can trigger inflammation and damage blood vessels.
“We know PM 2.5 can increase inflammatory markers in the body,” Chung said. “We also think, similar to smoking a cigarette, inhaling PM 2.5 can worsen atherosclerosis — plaque buildup in the arteries — and make plaques grow.”
According to Chung, pollution may also:
- Increase blood clotting
- Affect blood pressure
- Increase stiffness in blood vessels
- Raise overall cardiovascular risk
Scientists continue to study the connection between pollution and stroke risk, but evidence has become increasingly clear in recent years.
For instance, researchers at UHealth found a link between PM2.5 exposure and aneurysmal subarachnoid hemorrhage, a severe type of bleeding stroke caused by a ruptured aneurysm.
Utah Air Pollution and Stroke Risk
Utah’s geography creates unique air pollution problems throughout the year.
During winter inversions, cold air traps pollution close to the ground. In summer, wildfire smoke and heat can create similar air quality concerns.
The American Lung Association’s 2025 “State of the Air” report gave several Utah counties failing grades for ozone pollution, including Salt Lake, Utah, Weber, and Davis counties. (lung.org)
“We’re stuck between these two mountain ranges,” Chung explained. “We have the inversion, and we know that temperature worsens the health effects of pollution. We even know that different types of pollutants play various roles in increasing stroke risk. It's not just PM 2.5, which is what we typically measure. It’s also gases such as sulfur dioxide, ozone, carbon monoxide, and nitrogen, which are put out by various industrial processes. All of these play a different but additive role.”
Chung also said researchers can now track how pollution spikes affect stroke risk over time.
“We know that in different cities, when pollution levels spike, stroke risk spikes,” he said. “We can even figure out how many days after high pollution days that someone is at increased risk for stroke.”
Who Is Most at Risk from Air Pollution?
Although poor air quality affects everyone, some groups face higher risks.
“The people who are older, people who have chronic medical problems at baseline, who have had previous stroke [or] heart disease are all at greater risk than the healthy population,” Chung said.
Other higher-risk groups include:
- Adults over 60
- Individuals with diabetes or high blood pressure
- Children
- People living near high-traffic areas
He also noted that pollution has a “dose-dependent effect,” meaning health risks rise as pollution levels increase. So, figuring out how to lower your risk without loading the moving van is important.
How to Reduce Stroke Risk During Poor Air Quality Days
Doctors say small steps can help lower exposure during heavy pollution days.
“Masks are helpful; exercising indoors is helpful,” Chung said.
Other recommendations include:
- Check air quality forecasts
- Limit outdoor exercise during inversion days
- Use indoor air filtration when possible
- Reduce unnecessary driving
- Keep windows closed on smoky days
Chung also emphasized that communities can improve long-term health outcomes by supporting clean-air initiatives and reducing pollution sources.
“We do know that policies affect not just levels of pollution, but the health outcomes associated with those levels of pollution,” he said. “The biggest takeaway is that we can do something about it.”
As Utah enters another wildfire season, health experts hope greater awareness about air pollution and stroke risk will encourage Utahns to take steps to protect both their lungs and their brains.
Reviewed by our neurology expert:
Jennifer J. Majersik, MD, MS, vascular neurologist and Vascular Division chief, University of Utah Department of Neurology