Influence of indoor air temperature and relative humidity on learning performance of undergraduates

The indoor thermal environment plays an important role in learning performance, but many relevant studies have focused primarily on subjective evaluation and achievement evaluation of participants and paid relatively little attention to the physiological state. To study the effects of air temperature and relative humidity on the learning performance of undergraduates, experiments coupled with a questionnaire inquiry were conducted on undergraduate students subjected to eight different indoor air temperatures and relative humidity levels. The degree of discomfort, fatigue, distraction, and learning efficiency were measured and analyzed from psychological and physiological perspectives. These results showed that undergraduates performed better at 40% relative humidity and 24 degrees C. Learning performance variations were consistent with environmental comfort, but relative humidity impacted learning performances more than indoor air temperature. Low humidity environments decreased the overall learning performance; rooms maintained at 40% relative humidity lowered the degree of fatigue, reading speed, and the degree of distraction by 23.3%, 12.2%, and 61.1%, respectively, as compared to a room at 20% relative humidity. Therefore, relative humidity should be emphasized when designing learning spaces. This study also confirmed that pupil diameter could be used as a physiological index to evaluate fatigue and distraction.