Establishment of electromagnetic compatibility is important in use of electronic medical equipment in hospitals. To evaluate the electromagnetic environment, the electric field intensity induced by electromagnetic radiation in broadcasting spectra coming from outside the hospital was measured in a new hospital building before any patients visited the hospital and 6 months after the opening of the hospital. Various incoming radio waves were detected on the upper floors, with no significant difference in measured levels before and after opening of the hospital. There were no cellphone terminal signals before the hospital opened, but these signals were strongly detected at 6 months thereafter. Cellphone base stations signals were strongly detected on the upper floors, but there were no signals at most locations in the basement and in the center of the building on the lower floors. A maximum electrical intensity of 0.28 V/m from cellphone base stations (2.1 GHz) was detected at the south end of the 2nd floor before the hospital opened. This value is lower than the EMC marginal value for general electronic medical equipment specified in IEC 60601-1-2 (3 V/m). Therefore, electromagnetic interference with electronic medical equipment is unlikely in this situation. However, cellphone terminal signals were frequently detected in non-base station signal areas. This is a concern, and understanding signal strength from cellphone base stations at a hospital is important for promotion of greater safety.

Various static electricity countermeasures are taken in clean rooms� for preventing the pollution caused by particle adhesions. For working out a countermeasure�it is important to give consideration to the generation mechanism�characteristics and electrical charge of charged particles. However������������������������������������������������������������������������������������������� rooms have been established. Moreover�monodisperse and multi-charged particles are important as test particles for the basic study on their transport mechanism and deposition process. But�there are few studies on the charge control of these particles�those are relatively coarse and produced the manufacturing process. In this paper�the method for generating monodisperse and multi-charged particles is proposed�and the neutralization process of multi-���������������������������������������������������������������������������������������which can be utilized in an existing clean room�is also presented. It will be shown that the monodisperse and multi-charged particles can be produced with the proposed method�and that�by employing the DMA�multi-charged particles can be classified by their charges. The distribution of particle electrical charges after the neutralization corresponds well with that of equilibrated charges evaluated by the aerosol theory. The distributions of particle electrical charges in the atmosphere are also shown�that are measured with the presented system.

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