The study examined data on more than 10,000 heart attacks between 2002 and 2005. When the heart attack data were correlated with changes in air pollution levels, researchers in Italy found that an increase of 10 micrograms per cubic meter of fine particulate matter in the air correlated with a 0.01 percent increase in hospitalizations for heart attacks over the next two days. The researchers found a similar correlation between heart attacks and increases in carbon monoxide and nitrogen dioxide.
Fine particulate matter impacts human health because the particles are small enough to be inhaled deeply into the lungs, causing inflammation of blood vessels and irritation of nerves in the lungs. The primary source of fine particles are petroleum, coal, and other fossil fuels that are burned in cars, trucks, power plants, industrial plants, and furnaces used to heat homes and offices.
While the correlations in the latest study do not prove a specific causal link, they do add to a growing body of evidence suggesting that increases in fine particulate matter contribute to an increased risk of heart attacks, strokes, and lung disease. According to the American Heart Association web site:
- A 2007 study published in Circulation: Journal of the American Heart Association suggested that long-term exposure to air pollution from a nearby freeway or heavily trafficked streets is associated with a hardening of the arteries that could raise the risk of heart disease and stroke.
- A 2007 study presented at the American Heart Association's Annual Scientific Sessions indicated that increased roadway pollution produced by diesel fuel in vehicles is leading to a cascade of conditions that could result in heart attack or stroke.
- A 2007 study published in Stroke: Journal of the American Heart Association found that breathing fine particle pollution during warm weather months can increase stroke risk.
- A 2005 study published in Circulation: Journal of the American Heart Association suggested that inhaling diesel exhaust at levels typically found in large cities may disrupt normal blood vessel and clotting activity.