The Influence of Air Ions, Temperature, and Humidity on Subjective Well-being and Comfort Journal of Environmental Psychology, December, 1981
106 employees kept daily assessment records of their office environment and health over a 12-week period. Temperatures of about 23 degrees Celsius were associated with increased sensations of stuffiness, discomfort, and unpleasantness, and appeared to produce an increase in the number of complaints of headaches. The office environment was found to be depleted of small negative air ions. The introduction of a negative ion generator increased the subjective rating of alertness, atmospheric freshness, and environmental and personal warmth. Ions reduced the complaint rate for headache by 50% and significantly reduced the number of complaints of nausea and dizziness.