Effects of temperature and humidification in the office environment

In this investigation, the authors evaluated the relationship between temperature and (a) Sick Building Syndrome symptoms and (b) workers' perceptions of air dryness in environments with and without humidification. The authors studied the average intensity of symptoms and perceptions of dry air relative to room temperature in humidified and nonhumidified conditions. During the 6 wk of the experiment, 2 wings of the building were humidified one-by-one for 1 wk, followed by a week without humidification. A total of 230 daily questionnaires were completed during the nonhumidified period, and 233 were completed during the humidified period. The results were analyzed with linear regression analysis, and the average intensity of dryness symptoms and sensations of dryness increased with each unit increase in temperature above 22 degrees C, both in the humidified and nonhumidified conditions. Sick Building Syndrome symptoms increased relative only to temperature during the period of no humidification. In conclusion, temperatures above 22 degrees C caused increased dryness symptoms and a sensation of dryness, independent of humidification. The overall intensity of Sick Building Syndrome symptoms increased only when indoor air was not humidified.