A quantitative evaluation method for the biological effects |of ion‐current

An experimental apparatus called an ion‐current shuttlebox, was developed to evaluate quantitatively the biological effects of ion‐current in air. It consists of an ion‐generating long narrow cage for a rat and an automatic data acquisition system. The cage is divided into two parts, i.e., an ion‐exposing area and a control area. Ion‐current is generated by corona discharge of thin wires located above the cage. Two pairs of grids control the amount of ion‐current in the exposing area and eliminate ion‐current in the control area. In a computer simulation, the loci of ion‐particles were obtained which provide the appropriate conditions of potentials for the two grids. In basic experiments it was confirmed that ion‐current distribution is uniform in each area and is symmetrical between the two areas. The apparatus can expose ion‐current of between 0 to 1 μA/m² (continuously controllable) to a rat. A technique was devised which depresses the ozone generation by heating the corona wires. The behavior of a rat is recorded and analyzed in an automatic position sensing system controlled by a microcomputer. In sham exposing experiments, it was confirmed that this apparatus does not affect the circadian rhythm of the rat and there is no preference by the rat for either of the two areas.