Ask the doctor
Q. I live near a busy highway. Are there any heart risks from air pollution?
A. Yes. More than two decades of research has shown that air pollution can trigger heart attacks, strokes, and irregular heart rhythms, particularly in people who have or are at risk for heart disease. The most dangerous pollutants appear to be very tiny particles less than 2.5 micrometers in diameter, which the Environmental Protection Agency reports as PM2.5. These particles come from car and truck exhaust, power plants and other industrial sources, wildfires, and wood-burning stoves.
Because they’re so tiny, these particles are able to lodge deep in the lungs, where they irritate lung tissue. This inflammation then seems to spill out into the bloodstream and damages blood vessels, potentially contributing to cardiovascular problems.
Thanks to air quality regulations in the United States, particle pollution levels have dropped since the 1970s. This reduction appears to have translated to fewer deaths from both heart and lung disease, according to a long-term Harvard study of six cities.
Still, people—especially those with heart disease—should likely avoid exercising outdoors near busy roads or industrial areas. Sometimes, smog and haze will alert you to poor air quality, but often you can’t see the pollution. News outlets report the local Air Quality Index, a color-coded scale of pollution levels.
-Deepak Bhatt, MD, MPH
Editor in chief, Harvard Heart Letter