Significance of humidity and temperature on skin and upper airway symptoms.

The objective of the present study was to assess the effect of absolute and relative humidity, temperature and humidification on workers' skin and upper airway symptoms, and perceptions in the office environment. Associations between physical factors, and symptoms and perceptions were assessed in logistic regression models. At temperatures between 18 and 26 degrees C, relative humidity of 17-40%, and absolute humidity of 3.3-5.6 g H2O/kg air, skin symptoms and nasal dryness and congestion were alleviated by both kinds of humidity. Pharyngeal dryness increased when temperatures rose and was alleviated with a rise in relative humidity. Eye symptoms showed no dependence on humidity. Any kind of humidity increased odor sensation. Stuffiness increased when the air was humidified. In non-humidified conditions (21.3-22.7 degrees C, 20.0-31.7%, 3.3-5.6 g H2O/kg air), skin and nasal symptoms showed no association with humidity or temperature. Pharyngeal dryness diminished when humidity rose. In addition, the association between humidity and odor disappeared. In humidified conditions (21.5-23.7 degrees C, 26.6-41.2%, 4.2-7.0 g H2O/kg air), nasal dryness and congestion were alleviated by both absolute and relative humidity, and odor perception increased. Skin dryness and rash, pharyngeal dryness, and nasal dryness and congestion are alleviated in higher humidity. Steam humidification results in a risk for increased perception of odor and stuffiness.