Subjective response to negative air ion exposure.

This study investigated specific subjective or psychological effects of relatively long exposure to negative ions generated by a conventional air purification device. Subjects--24 males matched for age, education, physical condition, and smoking habits--were divided into a control (N = 12) and an ion exposure group (N = 12). The groups were subjected to 6 h normal and negatively charged atmospheres, respectively. The tests used were the Taylor Manifest Anxiety Scale (TMAS) and a self-report mood index. The analysis of TMAS change scores clearly showed no effect of negative ion exposure on anxiety. Analysis of mood index data showed significant changes in the subjective perception of both physiological state (relaxation increased) and psychological state (irritability, depression, and tenseness decreased while calmness and stimulation increased.