ABSTRACT
Air microbiology has long fascinated a few environmental microbiologists. Interest in air microbiology has been stimulated with the construction of relatively air-tight houses and buildings. Initially, the exposure of solid biological media to air provided the air microorganisms for study. Simple, gravity exposure of microbial media plates has demonstrated that the air in urban areas is more contaminated than the air in rural areas as far as bacteria, yeast, actinomycetes, and fungi are concerned. The isolation of specific organisms from air samples simply indicates their presence when the sample was collected and analyzed. Some air filters use finer materials to remove small particles. The use of humidifiers to adjust the moisture content of internal air can stimulate microbial growth that can be dispersed through central ventilation ducts to all parts of the building. The velocity of the discharge gases can carry the particulates high into the air, allowing wind currents to carry tiny particulates great distances.
