This report describes the objectives of and the events leading up to the establishment of the Society of "Human-Environment System" and forthcoming topics related to human living.

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Almost thirty years history of the Society of Human-Environment System was reviewed. Since 1977, the society had held Symposium on Man-Thermal Environment System every year and reorganized the symposium into the Symposium on Human-Environment System to extent the sphere of research to other problems of living environment. This paper presented an analytical review of about 800 submitted papers in 20 symposia and pointed out some themes for further studies.

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Humidity affects comfort in a number of ways both directly and indirectly. It is a factor in our energy balance, thermal sensation, skin moisture, discomfort, sensation of fabrics, health and perception of air quality. Reduced humidity in summer makes us feel cooler at the same temperature, our skin feels drier and less sticky, fabrics and clothing feel smoother and more pleasant to our touch and the air is perceived to be fresher. Much of the discomfort related to higher humidities appears to be due the higher levels of skin moisture, thus increased air speed alone is often effective in such environments. Further, the comfort and related benefits perceived by occupants and customers from humidity reduction may encourage and justify the design and implementation of HVAC systems with increased dehumidification capabilities such as Cold Air /Ice Storage systems.

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The site of noninvasive measurement of core temperature in human subjects should be selected in order to obtain accurate thermal information for the purpose of the experiments: average deep body temperature or thermal information regarding the central thermoregulatory mechanism.Esophageal temperature (Tes) has been preferably measured for average deep body temperature, since it mirrors closely central blood temperature.Rectal temperature (Tre) renders stable data in a steady state, not being influenced by the outer thermal environment or by shell temperature, but is not appropriate at least in experiments where rapid changes in body temperature are expected, since it is unable to follow relatively rapid changes in blood temperature. Tympanic temperature (Tty) has been measured as an indicator of brain temperature, which is considered to provide the major thermal input to the integrative center for thermoregulation. Intracranial temperature parallels Tty, while their changes are often preceded by those in Tes.The right and left Tty's are not always equal exactly, but may even change in opposite directions in many occasions where uneven blood flow occurs between the cerebral hemispheres, including unilateral cerebrovascular disorders. Regional or unilateral impairment of the balance between heat production in the brain and heat dissipation from it may elicit unevenness or asymmetry in the brain temperature which is reflected in the bilateral Tty's. Measurement of Tty is safe and causes no discomfort, if maneuvered properly. Measurement of aural canal temperature or infrared tympanic thermometry cannot substitute the direct measurement of Tty.Thermoregulatory responses are better correlated with Tty than Tes or other trunk temperatures.

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It is widely known that radiant temperature influences man’s thermal sensation together with air temperature, humidity, air movement and other human factors.The present study deals with a mean radiant temperature and a radiative heat transfer coefficient, which were derived by the present authors, having extended Gebhart’s absorption factor method on the radiation heat exchange. The newly derived mean radiant temperature and the radiative heat transfer coefficient have the following characteristics, that is, the former is weighted with the absorption factor between the human body and each surrounding wall, while the latter is defined by the product of three elements; -Stefan-Boltzmann’s constant, the temperature factor which relates to the third power of the absolute temperature, and the emissivity of the human surface, and not including the emissivities of the surrounding walls.

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In this study of sensory indicators to evaluate odor, we focused on Fanger's indicators which are based on unpleasantness of body odor and the others based on odor threshold value. We investigated the relationship between both indicators and points of attention to use the indicators in the management of indoor air quality. We distinguished indicators reflecting the quantity of odorous contaminants from the pollution source load on odor evaluation indicators. The correspondences between indicators based on unpleasantness of body odor and odor threshold value were examined. We found that the relationship between decipol and odor concentration reflecting the quantity of odorous contaminants is proportionate. The following three factors were considered in the employment of the odor evaluation indicator: the determination of acceptable levels, design of ventilation and deodorization based on estimation of the pollution source load, and check of the fulfilling the acceptable level and evaluation of ventilation and deodorization efficiency. We investigated the effectiveness of odor evaluation indicators from three kinds of viewpoint and strong and weak points of each indicator were obtained.

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KOTATSU is a well-known heating facility in Japan. It heats the lower extremities of a body by an infrared heater or a wood coal fire in a box. The objective of this paper is to clarify the thermal effect of KOTATSU on a person. Experiments were carried out under the following combined conditions: air temperatures were 11°C, 14°C, 17°C, and 20°C and infrared lamp levels were 'off', 'low', 'middle' and 'high' which correspond to 0W, 86W, 91W and 181W infrared heater consumption power, respectively. Five male and six female subjects participated in these experiments. The following results were obtained: 1) The skin temperature at the lower extremities of the body rose and that at the upper extremities dropped respectively, at the same time when a subject was seated at the KOTATSU. 2) The corrected operative temperature for indicating the effect of KOTATSU was introduced by the authors in the basis of heat balance equation between the human and its environment. This index correlates with the modified mean skin temperature and the thermal sensation for the whole body. Consequently, it is a suitable index to evaluate the thermal environment when a subject is seating at the KOTATSU. 3) The heating facility KOTATSU at 'middle' IR heater level has the equivalent effect of 8°C air temperature rise at 11°C air temperature, and also has more than 2°C effectiveness at 14°C air temperature even if the infrared lamp of the KOTATSU is turned off. 4) The corrected operative temperature fairly indicates the effect of thermal environment with KOTATSU in spite of non-uniform environment.

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The influence of cooling on lower limb muscles was measured by excitability of motor neuron pool in level of spinal cord as the Hoffmann reflex(H-reflex) response. Although current researches have discussed about the recruitment threshold of motor units(MUs) activity, the changing of cutaneous temperature by cooling has not been examined. This study analyzed 1) the change in the excitation of the motor neuron pool, which was indicated by the amplitude of the Hoffmann reflex measured for muscles of the leg when the skin temperature was lowered , and 2) the manner in which afferent nerve inputs were integrated in the motor neuron pool. The subjects were seven healthy males without a previous history of neural diseases. The distribution of skin temperature in the leg was obtained thermographically, and the amplitude of the Hoffmann reflex of the soleus muscle was measured using a pair of Ag-AgCl electrodes(diameter=8mm) which were attached to the skin surface at the midline of the back of the calf; the skin temperature was subsequently lowered from 33.1°C to 22°C. The motor neuron pool exhibited maximum excitability when the skin temperature was 26 °C; at this time the amplitude was approximately 43% greater than when the skin temperature was 33.1 °C(control : without cooling condition). The excitability of the motor neuron pool decreased steadily at skin temperature above and below 26 °C, and was at a minimum when the skin temperature was 22 °C. The present study showed that the amplitude of the Hoffmann reflex was significally affected by the lowering of the skin temperature.

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The objective of this paper is to develop an environmental index describing the effect of outdoor climate on the human thermal sensation, i.e.,' a sensational climate'. To evaluate a sensational climate of the principal cities and towns in JAPAN, a new index has been developed. A new index called 'Predicted Comfortable Clothing' (PCC in clo units) was developed based on the human heat balance equation. This index can evaluate the combined effect of air temperature (Ta), humidity, wind speed, solar radiation and metabolic rate. In the course of development, the corrected humid operative temperature (HOTV, Horikoshi et al. 198?) was further developed to indicate the sensational climate in considering the effect of solar radiation . The temperature-humidity index (THI) was also applied for the evaluation of a sensational climate. These indices were calculated using the weather data observed at 154 cities and towns where the principal observatories are located. Result showed geographical distribution of and the annual fluctuations of outdoor climate of the typical 10 sites out of 154 cities. In summer, Ta in Naha was highest throughout a year as compared with other cities, but PCCs in Matsuyama and Kyoto were -0.5 clo vs -0.25 clo in Naha. In winter, there were significant differences of Ta between Niigata, Shinjo and Karuizawa, but their PCCs were little differences. This indicates that air temperature may be a principal variable but may not evaluate the effect of outdoor climate properly with regard to the human thermal sensation and demonstrates that the newly developed index, PCC may be a powerful tool for evaluating outdoor climate.

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In this study, local evaporation rates (msk) at chest, front thigh and forearm were measured with local calorimeters and local sweat rates (msw) were simultaneously measured with ventilated capsules at the same regions while a subject was exposed to the heat (46-48°C) for one hour. During the first 30-40 minutes, msk increased progressively with msw and became appreciably less than msw after the skin region was fully wetted with sweat. Thus, the critical msk value can be clearly identified during the heat exposure so as to determine local evaporative heat transfer coefficients. The results showed that the he values for chest, front thigh and forearm were 5.5, 6.1 and 7.3 (kcal/m2.h.mmHg), respectively.

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