Each year study families were requested to participate in the cold air challenge protocol. Subjects participating in this protocol were studied in a laboratory at the community health center. Forced expiratory volumes were obtained followed by a cold air challenge test using the technique of eucapneic hyperventilation with subfreezing air. The cold air challenge test separated normals from asthmatics. Two inhalations of isoproterenol were administered one minute apart after which three forced vital capacity maneuvers were performed. After pulmonary function tests were completed, allergy tests were conducted for ragweed, trees, house dust, and grasses.