Asthma is a chronic lung disease caused by inflammation of the lower airways and episodes of airflow obstruction. Asthma episodes or attacks can vary from mild to life-threatening. In 2007, about 7% percent of the U.S. population was diagnosed with asthma and there have been a growing number of new cases since that time. There are several known risk factors identified as triggers of asthma symptoms and episodes, including inhalation of allergens or pollutants, infection, cold air, vigorous exercise, and emotional upsets. There is also growing evidence relating body-mass index to asthma in both children and adults. Design a study to investigate whether there is such an association.