A new study has found that long-term exposure to air pollution may silently damage the heart—even before any symptoms of disease appear.
Using advanced heart imaging techniques, researchers discovered that people living in areas with higher levels of fine particulate matter in the air had early signs of heart scarring, a change that can lead to serious heart problems later in life.
The research, published in Radiology, was led by Dr. Kate Hanneman from the University of Toronto and the University Health Network. It sheds light on how air pollution, especially fine particles known as PM2.5, affects the heart at a tissue level.
These tiny particles, which come from things like car exhaust, industrial smoke, and wildfires, are small enough to be inhaled deep into the lungs and even enter the bloodstream.
“We already know that people exposed to air pollution are at a higher risk of heart disease and heart attacks,” said Dr. Hanneman. “What we didn’t fully understand is what’s happening inside the heart to cause that risk.”
To find out, Dr. Hanneman and her team used cardiac MRI, a noninvasive scan that shows the heart in high detail. They looked at myocardial fibrosis—a kind of early scarring in the heart muscle that weakens its ability to pump blood and can lead to heart failure.
The study included over 690 people: 201 healthy individuals and 493 patients with dilated cardiomyopathy, a heart condition where the heart becomes enlarged and pumps less efficiently.
The researchers found that people exposed to higher levels of PM2.5 over the long term had more signs of fibrosis in the heart muscle—regardless of whether they already had heart disease or not.
Surprisingly, even people living in areas where pollution levels were within current global guidelines still showed these early signs of heart damage. This suggests that even low levels of pollution may not be safe for the heart.
Certain groups seemed to be affected more strongly: women, smokers, and people with high blood pressure showed the most pronounced changes. According to Dr. Hanneman, this finding emphasizes how air pollution could be an overlooked contributor to heart disease risk—one that goes beyond traditional factors like smoking or obesity.
Understanding a person’s long-term exposure to air pollution might help doctors assess heart disease risk more accurately in the future.
For instance, someone who works outside in polluted air every day could be at higher risk, even if their other risk factors are low. Dr. Hanneman believes doctors may one day include air quality exposure in regular health assessments.
“This study shows that air quality plays a significant role in shaping the structure of the heart, potentially setting the stage for future heart problems,” she said.
The findings also have important public health implications. They suggest that current air quality standards may not be protective enough and that further efforts are needed to improve air quality—even in places like Canada and the United States, where pollution levels have been reduced over the past decade.
Dr. Hanneman noted that this research also shows the growing role of radiology in environmental health, saying that imaging tools like MRI can help scientists uncover how pollution and other environmental exposures affect the body, organ by organ.
In summary, this study highlights a hidden cost of air pollution: silent damage to the heart that could lead to serious illness over time. It underscores the need for cleaner air—not just for the lungs, but also for the heart.
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The research findings can be found in Radiology.
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