Moulds, bacteria and insect-derived matinal produce disease and hypersensitive and allergic responses in many individuals. Aeroallergens, including allergens in ambient air, have not been fully studied. Airborne micro-organisms such as bacteria in tropical developing countries may be responsible for such diseases as cerebrospinal meningitis, Q-fever, histoplasmosis, anthrax and coccidioidomycosis. In addition to bacteria, biological air pollutants include viruses which cause a great number of viral diseases including influenza