Airborne viable particles and total number of airborne particles: comparative studies of active air sampling.

This paper presents results from a comparative study of different impaction air samplers under simulated operational conditions in a controlled environment. Furthermore measurements have been performed in a body-box during evaluation of clean-room clothing and in a day care center. Microbial monitoring of controlled environments can be performed in several ways, and with the aid of different sampling instruments. Knowing the limitations of the chosen system is of vital importance for the correct evaluation and interpretation of the results. The number of Colony Forming Units (CFU) detected by one method cannot be directly compared with results from another method. The obtained results seem to indicate that in a controlled environment the exposure situation with a human contamination source gives an approximate relationship between the total number of airborne particles and the number of aerobic airborne viable particles detectable with standard methods.