Human Comfort and Productivity under Humidity Conditions with Different Indoor Air Quality Levels in Summer and Winter

Subjective experiments were conducted during the summer season and the winter season in order toclarify the multiplied effects of humidity and indoor chemical pollutants on subjective comfort and productivity. Lower concentration of formaldehyde was observed at low humidity than at high humidity. Subjects rated the acceptability of air lower at the beginning of the exposure in the environments polluted with formaldehyde. On the other hand, lower humidity caused subjects to rate air quality higher in clean air. Mucous irritation of the eyes, nose and throat due to formaldehyde was found in winter, though not in summer. Break up time of subjects eyes observed in winter was shorter than in summer. Subjects complained of having difficulty concentrating under polluted conditions. Their performance was found to be lower. Subjective performance was found to behigher under high humidity conditions in winter.