In brief: Heart aches for clean air

In brief

Heart aches for clean air

In the blame game for heart disease, the major players are smoking, poor diet, lack of exercise, and genes. But some studies suggest that bad air also belongs on the team. Pollution researchers have coined the term "environmental cardiology" for studies linking poor air quality to heart attacks and strokes. In June 2004, the American Heart Association threw its weight behind the research by officially identifying air pollution as an important cardiovascular risk factor.

Much of this research has focused on particles small enough (equal to or less than 2.5 micrometers in diameter) to be drawn deeply into the lungs. The main source is combustion: gasoline in car and truck engines, coal or oil in power plants, and wood in fireplaces. Chemically, the particles (often referred to as fine particulate matter) consist mainly of sulfates, nitrates, acids, metals, and carbon with other chemicals stuck to their surfaces.

Starting in about the mid-1990s, epidemiologists at Harvard and elsewhere began to look beyond the lungs and investigate how air pollution might affect cardiovascular disease. Some initial findings were questioned. Now, though, there's not much doubt about the connection between the fine particles and cardiovascular disease. The association isn't nearly as strong as it is with cigarette smoking, which doubles a person's chances of dying from a cardiovascular disease. Still, it's sizable. A review of studies published in 2004 in Circulation found that each 10-microgram-per-cubic-meter increase in particle pollution hikes cardiovascular disease risk by 8%–18%. Put another way, breathing the air in a polluted city increases cardiovascular risk about half as much as living with a smoker.

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