The reviews on the indoor air environment researches starting from the history, followed by the situation of the study about the indoor air quality (IAQ) problems brought by artificialization of the indoor environments are made. The author also describes the effects of the ventilation and establishment of environment guideline as technical and administrative measures.

The use of air-conditioning in offices located in hot-humid regions creates differences between indoor and outdoor air temperatures. Previous studies, which focused on artificial environments, found that air temperature step changes affect human thermal sensations and comfort. However, their effect on workers’perceived arousal has been rarely discussed. The purpose of the present study is to evaluate the effects of air temperature step changes (both up-step and down-step) on thermal perception and perceived arousal.

Thirty-seven workers from two offices in Jakarta responded to a rating scale questionnaire about thermal perception that covered the following sub-topics: overall and local thermal sensations, thermal comfort, satisfaction, adjustment, and perceived arousal (i.e., alertness, freshness, and concentration) during working time. Air temperature and relative humidity around the subjects were recorded every 5 minutes by a data logger, from 10:00 to 17:00. During lunch time, the subjects walked to a nearby restaurant, exposing themselves to non-shaded outdoor temperature before returning to the office.

Office A workers experienced larger temperature changes than Office B workers. Indoor and outdoor temperatures of Office A were 22.9 °C and 32.1 °C, respectively, whereas, for Office B they were 24.2 °C and 29.5 °C, respectively. Perceived arousal decreased significantly in Office A after the workers experienced the change in air temperature. However, no significant difference in perceived arousal was registered in Office B, likely due to a larger gap between indoor and outdoor air temperatures in the case of Office A. The data of just before and after the temperature step changes were analyzed: no negative correlations were found between changes in the overall thermal sensation and alertness (p<0.05), freshness (p<0.05), or concentration (p<0.01). Therefore, warm sensations after the air temperature changes, associated with a hysteresis effect, should have lowered the perceived arousal. Our findings suggest that thermal perception and perceived arousal are altered by relatively large changes in air temperature. These changes are determined not only by the range of air temperature steps, but also by the air temperature experienced previously. In addition, mild air temperature changes in the actual environment, combined with exercise, food intake, and direct radiation exposure, induced warmer thermal sensations than those simulated through laboratory experiments.

This study aimed to investigate clothing characteristics and indoor-outdoor thermal comfort of Japanese youth for an air-conditioned room in summer. A field investigation was conducted on the clothing and thermal comfort of 90 participants in Fukuoka, Japan. The main results concerning clothing were that six and five summer clothing types constituted typical summer ensembles for males and females, respectively; there was some stability in clothing characteristics over time. Concerning thermal feelings, females felt cooler or colder and felt more airflow in the room compared with males. Females also felt that conditions were significantly more comfortable and tolerable, and with less airflow, outside and were more sensitive to perceived the local differences. Males tended to adapt to the indoor environment more easily, but had difficulty in perceiving local differences in thermal feelings. Concerning the relationships between clothing and thermal feelings, the local thermal sensation was affected by the clothing conditions of different body parts and the humidity feeling was affected by clothing insulation, especially for males. Accordingly, stability, relationships, gender and local differences should be taken into account in the design solutions for summer clothing and living environments.