By Daily Mail (U.S.) | Created at 2026-06-09 18:22:17 | Updated at 2026-06-12 22:01:05
3 days ago
Millions of people may be at a heightened risk of heart disease due to exposure to daily pollutants.
Researchers from Canada and the US examined the relationship between long-term air pollution exposure and coronary atherosclerosis, sometimes called coronary artery disease (CAD).
CAD is the narrowing of the arteries that supply blood to the heart caused by the buildup of cholesterol, fats and plaque within the arteries. This restricts blood flow and increases the risk of heart attacks.
Approximately five percent of American adults have been diagnosed with CAD, translating to up to 18 million Americans.
Researchers looked at the relationship between long-term exposure to two common pollutants in urban air: ambient fine particulate matter (PM2.5) and nitrogen dioxide (NO2).
PM2.5 is made up of microscopic particles from sources like car exhaust, power plants, wildfires and fuel burning. These particles are so tiny that they can penetrate deep into organ tissue and even enter the bloodstream.
NO2 is a harmful gas produced by burning fossil fuels in cars, power plants and industrial processes.
The team found that for each one microgram per cubic meter of long-term exposure to PM2.5, there was an 11 percent increase in calcium build up in the coronary arteries - a process called atherosclerosis, which stiffens blood vessels and raises the risk of CAD - 13 percent increased odds of more plaque and 23 percent greater odds of obstructive CAD.
Estimates suggest about half of Americans are exposed to concerning levels of air pollution. Above, smog is seen lingering above Los Angeles in 2024
Exposure to NO2 showed similar upward trends in risk with increased exposure, but with smaller increases.
The team analyzed data from 11,128 adults who had undergone cardiac CT exams from 2012 through 2023 across three major hospitals in Toronto.
The researchers linked the patients' zip codes with air quality data to estimate each's average exposure to air pollution over the 10-year period prior to the CT scan.
Three heart health markers were measured: calcium score, total plaque and artery narrowing.
After reviewing the images and comparing them to air quality, results showed the increased heart health risks among people with higher exposure to air pollution.
Senior author Dr Kate Hanneman said: 'This is one of the largest studies to use cardiac CT to show that air pollution is linked to more advanced coronary artery disease - going beyond calcium scoring to include total plaque burden and obstructive disease - in a population with moderate exposure levels typical of high-income countries.'
The findings also showed that levels of air pollution below or near regulatory standards and those at levels of typical urban environments are still associated with early signs of heart disease, often even before symptoms appear.
Researchers wrote this highlights the 'importance of improving air quality to reduce' cardiovascular disease (CVD) risk.
Hanneman added: 'Even at exposure levels below current Canadian air quality standards, long-term air pollution was independently associated with more advanced coronary artery disease - suggesting current regulations may not be fully protective and that air pollution belongs alongside blood pressure, cholesterol and smoking as a modifiable cardiovascular risk factor.'
Exposure to air pollution, in particular PM2.5, has been tied to an array of chronic health conditions affecting all organ systems in multiple previous studies.
Previous studies have shown that short-term pollution exposure, on the order of hours to days, is associated with increased emergency department visits for ischemic heart disease, admissions for heart failure and greater use of medical imaging.
Symptoms of coronary artery disease (CAD) include fatigue, chest pain and shortness of breath, while a complete blockage of blood triggers a heart attack
While research has shown that exposure over the longer term, months to years, is linked to increased risks of myocardial infarction, stroke and cardiovascular mortality.
The researchers wrote that air pollution is the leading environmental risk for CVD worldwide, contributing to 2.5 million CVD-related deaths each year.
And the World Health Organization calls air pollution 'one of the greatest environmental risks to health,' playing a major role in causing heart attacks and strokes.
The researchers said their findings may 'open the door to incorporating environmental exposure history into cardiovascular risk assessment, like clinicians would ask about smoking and family history.'
In the body, PM2.5 sparks inflammation, constricts blood vessels – raising blood pressure and promoting artery-narrowing plaque – and triggers oxidative stress, damaging cells, mitochondria and DNA from head to toe.
Estimates suggest about half of Americans are exposed to concerning levels of air pollution.
Symptoms of CAD include fatigue, chest pain and shortness of breath, while a complete blockage of blood triggers a heart attack.
Treatment for CAD includes medications, surgery and lifestyle changes, such as getting more exercise, eating healthier and quitting smoking.
