The present invention comprises a method, materials and apparatus for investigating asthma in humans using dust mite allergen. The dust mite allergen is prepared to be of a controlled size such that particles are respirable, effectively aerosolized, and deliver a significant amount of allergen. The dust mite allergen is applied in a controlled manner within an environmental exposure chamber to elucidate the etiological links between dust mite allergen concentration and asthma response in humans. The environmental exposure chamber is specially-designed to promote homogeneity of allergen concentration. Preferably, the dust mite allergen preparation comprises particles having an average diameter of less than 25 microns, and more preferably 5-10 microns. Correlation between aerosolized particle count and allergen concentration enables “real-time” allergen concentration estimates without the use of expensive and time-consuming assay techniques.
