ClinicalTrials.gov has a full list of NIAID-funded clinical studies related to asthma.
What is Asthma? from The National Heart Lung and Blood Institute.
Asthma Statistics from The Centers for Disease Control and Prevention
Medical Encyclopedia: Asthma from MedlinePlus
Of Air and Asthma: Air Pollution’s Effects from NIH news in Health
Division of Allergy, Immunology, and Transplantation
Allergic Diseases