Far too many Americans -- about 25 million people -- are intimately acquainted with the symptoms of an asthma attack. When asthma strikes, your airways become constricted and swollen, filling with mucus. Your chest feels tight -- you may cough or wheeze -- and you just can't seem to catch your breath. In severe cases, asthma attacks can be deadly. They kill more than 3,000 people every year in the United States.
Asthma is a chronic, sometimes debilitating condition that has no cure. It keeps kids out of school (for a total of more than 10 million lost school days each year, according to the Centers for Disease Control) and sidelines them from physical activity. Employers lose 14 million work days every year when asthma keeps adults out of the workplace. The disease is also responsible for nearly 2 million emergency room visits a year.
Understanding what might trigger an asthma attack helps asthma sufferers keep their disease in check. Sometimes it's as simple as avoiding dust, tobacco smoke or cockroach droppings. But what if the air outside your home is filled with asthma triggers?
In recent years, scientists have shown that air pollution from cars, factories and power plants is a major cause of asthma attacks. And more than 131 million Americans -- over 40 percent of the nation's population -- live in areas with bad air. Roughly 30 percent of childhood asthma is due to environmental exposures, costing the nation $2 billion per year. Studies also suggest that air pollution may contribute to the development of asthma in previously healthy people. In fact, one recent Los Angeles study found that eight percent of childhood a