Impact of Indoor Humidity, Local Air Velocity and Illuminance on Subjective Comfort, Performance and Fatigue

A subjective experiment was conducted using 15 college-aged subjects of both genders in order to evaluate their physiological and psychological reactions, performance and fatigue under the different combinations of indoor humidity, local air velocity and illuminance.
The five-hour exposure periods were divided into three sections of 1.5 hours by 10-minute breaks. During each section, subjects performed 3 times of 20-minute task. During the exposure time subjects rated their sensations, visual fatigue and general fatigue, and measured their break up time (BUT) and skin moisture after each task.
Higher rate of complaints related to visual fatigue was reported under the condition with local air velocity than without it at the same humidity. High humidity caused subjective low visual fatigue. Subjective BUT was shorter in the environment with local air velocity or at low humidity, where people rated greater eye dryness sensation. High illuminance caused no difference in occupants physiological and psychological reactions although correct answer rate was higher in environment with high illuminance.