The Real Dangers of Air Pollution

Studies show it damages the heart and lungs, but most people have little to fear.

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It doesn't take a rocket scientist to figure out that there are better things you could do for your health than take deep breaths on a smoggy day. A growing pile of research suggests that even relatively low levels of air pollution may be more harmful than previously realized, to both heart and lungs. The latest salvo from researchers, published this week in the New England Journal of Medicine, focuses on how particulate matter from air pollution affects lung function. The new research buttresses studies (here and here) published earlier this year by the same journal showing that air pollution contributes to heart problems. How much should you worry? U.S. News asked leading experts to put this latest news in context. Some key questions and answers:

 What is particulate pollution?
According to an American Lung Association report, particulate pollution refers to the mix of solid and liquid particles in the air that can come from natural sources, such as dust storms or wildfires, or from such human activity as the burning of fossil fuels in factories or the use of diesel engines. Other particulates are produced when certain chemicals and substances react with one another in the atmosphere.

What is the danger to my heart and lungs?
The effect of low levels of particulate pollution found in many urban areas is not unlike secondhand smoke, experts say. Studies show that short-term adverse effects from particulates include diminished lung function, coughing, wheezing, cardiac arrhythmias, and heart attacks. Long-term exposure can also worsen asthma, slow normal lung growth, damage lung airways, and increase the risk of dying from lung cancer and cardiovascular disease.

How big is the risk to me?
Certain populations, such as the very old and the very young, are the most vulnerable to air pollution. However, even the most alarming studies conducted in the most polluted areas suggest that the average person's individual risk from exposure is very slight. Relative risk numbers often seem more frightening than they actually are, says Erik Rifkin, an environmental scientist and the coauthor of a book about assessing health risks titled The Illusion of Certainty: Health Benefits and Risks. For example, an earlier study published in the New England Journal of Medicine found that short-term exposure to traffic fumes tripled the risk of heart attacks in heart-attack survivors. What's easily forgotten, says Rifkin, is that the risk was extremely small to start with. Jogging or having sex, for example, could elevate the risk of a heart attack by a similar amount, says Robert Brook, a cardiac physician at the University of Michigan.

What's the big deal if the risk to an individual is small?
From a public health perspective, even a tiny increase in risk multiplied by millions of people translates into tens of thousands of unnecessary illnesses, hospitalizations, and premature deaths, experts say. The Environmental Protection Agency estimates that each year some 65,000 Americans have cardiac events associated with uncontrolled air pollution levels.

How can I protect myself?
Short of moving to the countryside or at least away from busy roads, shielding yourself from the effects of air pollution is not easy. Masks won't work, as many particles can slip right through. At the very least, suggests Murray Mittleman, a cardiologist at Harvard University, people who regularly exercise outdoors near highways may want to consider remapping their route.

How can I find out about the quality of the air in my local area?
The American Lung Association has a Web tool that allows you to type in your ZIP code and get a detailed report on the air quality in your area. You'll find everything from grades for particulate and ozone pollution (Chicago gets an F for particulates, for example, while Cheyenne gets an A) plus a breakdown that shows how many unsafe pollution days the region has had and how many people in the area are at high risk.