Asthma: What Brought on the Epidemic?

The rates of childhood asthma in the United States rose 160% from 1980 to 1994 and have remained high ever since, making this chronic lung illness the country's third most common pediatric disease. QUEST meets Bay Area researchers who are investigating possible environmental and social culprits. Their understanding of asthma's causes could one day lead to measures to prevent kids from developing the disease.