Evaluation of the commercial bacterial air samplers by the new bacterial aerosol generator

Of late microbiological air samplers of various types have been developed in monitoring the critical areas in the hospitals and pharmaceutical plants. It has not been clarified, however, that a commercial air sampler is the most suitable for such a purpose. The present studies were conducted to investigate the bacterial collection efficiency of these air samplers. The new experimental apparatus basically consists of a bacterial aerosol generator and an isokinetic sampling steel air duct. Serratia marcescens was used as the test bacteria, and then the bacterial collection efficiency of the three kinds of commercial air samplers (Andersen air sampler, Pin-hole air sampler and M/G air sampler) was examined. It was found that in these experiments these three air samplers had a high bacterial collection efficiency. All except 0.3 to 2.0% of the small bacterial particles (1 to 5 micrometer) were trapped by these tested air samplers. Furthermore, in these three air samplers it was also confirmed that for collecting the hospital airborne bacteria the bacterial collection efficiency was more than 99.9%. The authors' findings showed that these three air samplers were designed according to Ranz and Wong's theoretical and experimental results.