A new study has found that breathing in common air pollutants over many years is linked to early signs of heart disease—even when the air quality is within or close to legal safety limits.
The research also shows that men and women may be affected in slightly different ways. These findings were shared at the annual meeting of the Radiological Society of North America (RSNA) and involved over 11,000 adults.
Air pollution is a major global health issue. According to the World Health Organization, it is one of the biggest environmental risks to our health and is a leading cause of heart attacks and strokes. A 2021 study found that air pollution caused about 2.46 million deaths related to heart disease that year alone.
The researchers in this new study looked at two common types of air pollution found in cities: fine particulate matter (called PM2.5) and nitrogen dioxide (NO2). PM2.5 includes tiny particles that come from car exhaust, factory emissions, and smoke from wildfires.
These particles are so small—about 30 times smaller than a human hair—that they can travel deep into your lungs and even enter your bloodstream. NO2 is a harmful gas that mostly comes from burning fuels in cars, power plants, and factories.
To understand the connection between air pollution and heart health, the researchers used cardiac CT scans from people who had imaging tests between 2012 and 2023 at three large hospitals in Toronto, Canada.
They combined this medical data with information about air pollution levels in the neighborhoods where the patients lived. This allowed them to estimate how much air pollution each person was exposed to over a 10-year period.
The scientists then looked at three signs of coronary artery disease: calcium buildup in the arteries, total plaque (fatty deposits) in the arteries, and the narrowing of arteries, which can block blood flow.
Their results were concerning. For every small increase in PM2.5 pollution—just 1 microgram per cubic meter—there was an 11% increase in calcium in the arteries, a 13% higher chance of having more plaque, and a 23% higher chance of having narrowed arteries.
Exposure to nitrogen dioxide was also linked to more heart disease, although the effects were slightly smaller.
Both men and women were affected, but there were some key differences. In women, long-term exposure to fine particles was more strongly linked to high calcium levels and severe artery narrowing. In men, it was connected to high calcium levels and more plaque overall.
Dr. Felipe Castillo Aravena, the study’s lead author, said that even at low levels of pollution, there was more plaque in the heart’s arteries. This suggests that people may be at risk of heart disease even if they live in places where air pollution meets current safety standards.
The study’s senior author, Dr. Kate Hanneman, noted that this is one of the largest studies to examine how modern-day pollution affects different aspects of heart disease.
She emphasized that heart disease is the top cause of death around the world, and that air pollution is a modifiable risk factor. In other words, it’s something that society can change—by improving air quality—to protect people’s heart health.
While more research is needed to understand exactly why women and men are affected differently, this study highlights how important clean air is for everyone. These findings also support the idea that reducing air pollution could help prevent heart disease long before symptoms appear.
If you care about heart disease, please read studies that herbal supplements could harm your heart rhythm, and how eating eggs can help reduce heart disease risk.
For more health information, please see recent studies that apple juice could benefit your heart health, and results showing yogurt may help lower the death risks in heart disease.
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