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Matters of the Heart: Air Pollution and Cardiovascular Disease

EPA scientists explore the link between elevated ozone and heart disease risks

Heart image with an EKG line going through.

Most people don't pay much attention to the constant thump-thump, thump-thump, thump-thump, of their heart beating away in their chest. After all, the prescription for heart health is generally well known - a tried and true combination of eating a low fat, high-fiber diet, not smoking, staying active, and keeping your blood pressure and cholesterol level in check. For some, a doctor-recommended daily dose of aspirin is part of the routine.

Now, however, emerging EPA research is pointing toward what could very well be an important missing ingredient, especially for those already at risk of heart attacks: keeping an eye on your local air quality index.

"Five percent or more of heart disease deaths are possibly related to air pollution exposure," says Wayne Cascio, MD, Director of EPA's Environmental Public Health Division.

Dr. Cascio, a cardiologist, and his research team are exploring the potential effects of air pollution exposure on cardiovascular health. He is also the leading force behind the Agency's "Green Heart Campaign" to increase awareness among public health professionals, doctors, nurses, other healthcare providers, and individuals that air pollution is a risk for those with heart disease.

The effect of air pollution exposure on the lungs has been well studied. Research shows that breathing in increased levels of tiny particles of air pollution (fine particulate matter or PM2.5) and ground-level ozone can lead to lung inflammation, decreased lung function, and an increase in asthma attacks. Extensive studies have also shown that particulate matter can contribute to and cause cardiovascular problems.

And now EPA researchers are exploring the link between ozone exposure and cardiovascular health.

Researchers in Cascio's division have discovered that ozone exposure can trigger inflammation of the vascular system and increase risk factors associated with heart disease.

"We found a linkage between ozone and increases in two risk factors for heart disease: a change in heart rate variability and a reduction in the ability of blood clots to dissolve," said Robert Devlin, Ph.D., an EPA senior scientist and lead author on a paper published in the American Heart Association's journal Circulation that describes one of the first studies looking at the effects of ozone exposure on heart health.

Cascio, Devlin, and other EPA researchers are planning additional studies and will expand the suite of factors they examine, including exploring the impacts of ozone on resting heart rates versus the impacts while exercising. This type of test, similar to cardiac stress tests routinely performed in doctors' offices, will give insights into the potential for ozone exposure to trigger the heart to beat irregularly, too fast, or too slow.

EPA's research on air pollution and cardiovascular disease provides key information to public health officials and health care providers, who can then use it to issue advisories that alert those at risk to take action, such as limiting outdoor activities during periods of elevated ozone and "Air Quality Action" days.

With increased awareness of a link between air pollution and heart health, Cascio hopes people will keep themselves informed about their local air quality conditions. That information is readily available through EPA's Air Quality Index (AQI) and the AirNow App, a free smartphone App (available on iPhone and Android) that provides real-time air quality information. A tool called EnviroFlash also provides email and text message updates about local air quality data. "EnviroFlash is an easily accessible tool to help people plan activities around periods of increased ozone levels and other air pollutants," says Cascio.

Learn More

EPA Clean Air Research

EPA Air Research on Cardiovascular Disease

NY Times: Inhaling dirty air can cause heart attacks and brain loss Exit EPA Disclaimer

EPA Tip Sheet on Air Pollution and Heart Disease—Reduce your exposure to contaminants

Circulation Article by Dr. Devlin on Ozone Exposure and Heart Health

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