ABSTRACT
Airborne microorganisms present in the air are removed by air sterilizers and subsequently used for aerobic fermentation. There is a wide variation in the quantity of suspended particles and microbes in the outdoor air. The microorganisms present may vary from 10 to 2000/m3, while the suspended particles may be from 20 to 10,000/m3. The microorganisms present in the air usually contain fungal spores (50%) and Gram-negative bacteria (40%). Airborne microorganisms mainly consist of species of bacteria, bacterial spores, yeast, fungi, and viruses. The size of these organisms varies from 0.5 µm to several hundred micrometers. The airborne particles destroyed or collected during air sterilization are usually of the size of small bacteria, namely, 0.5–1 µm. However, in some typical cases, the size of the microorganisms may vary. The flow pattern of the particles deviates from those of air flow due to the inertia of the particles as they approach the cylindrical surface.
