RELATION BETWEEN PARTICLES AND MICROORGANISMS IN NONFILTERED INDOOR AIR

Usually airborne microorganisms are adherent to particles. As the regi stration of particles is easier and faster than the determination of m icroorganisms in the air, it may be suggested to count only the partic les in routine hygienic controls. The present investigation shows, tha t a relation of 1 : 200 (microorganisms : particles) results if partic les greater than or equal to 5 mu m are considered. Because of the wid e range of scatter of the determined values and the specific utilizati on of the investigated rooms this relation cannot be generalized for o ther fields of activity. A general substitution of the determination o f microorganisms in the air by the registration of particles is not po ssible. However, for particular clean room areas it is possible to est imate the microbial contamination of the air by means of counting the particles greater than or equal to 5 mu m if an adequate pool of singl e determinations is available.