The purpose of this study was to assess temporal changes in the concentrations of bioaerosols in a laboratory mouse room (LMR) and a laboratory rabbit room (LRR) and to determine environmental factors associated with the total bacteria and fungi concentrations. The concentrations of total airborne bacteria and fungi in the LMR and LRR were sampled once a month from March, 2011 to February, 2012. The total bacteria concentrations in the LMR showed a gradual increase during the summer, while the highest concentrations in the LRR were noted in July and November. The total fungi concentrations showed a similar seasonal pattern of change in the LMR and LRR with a noticeable increase during the summer. Relative humidity (RH) was the environmental factor most associated with the concentrations of total bacteria and fungi. Temperature, CO2 and illuminance were also slightly associated with total bacteria and fungi concentrations. The overall airborne microbe concentrations were significantly greater in the LRR than in the LMR. Airborne microbe concentrations in the LMR and LRR varied greatly depending on seasonality, and these changes were affected by environmental factors..

Key words: Laboratory animal room, total bacteria, total fungi, relative humidity, illuminance, seasonality.

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