The effect of air humidification on symptoms and perception of indoor air quality in office workers: a six-period cross-over trial.

An evaluation of the effect of air humidification on various factors was performed, including skin dryness and mucosa, allergic and asthmatic reactions and perception of IAQ. A six period cross over trial was conducted on 290 office workers. A total of 211 workers who returned at least two weekly diaries and who had experienced both humidified and nonhumidified conditions were included in the analyses. The main outcome was characterized by dryness, irritation or itching of skin and eyes, of the throat and nasal dryness. The 'dryness symptom score' was significantly smaller during the humidified phase than during the reference phase. States that the results suggest that dryness of skin and mucosa, allergic reactions, and sensation of dryness can be reduced by proper air humidification.