Subjective Evaluation for Perceived Air Pollution Caused by Human Bioeffluents

The concentration of carbon dioxide is used as an important index of indoor air quality representative of body odor or bioeffluents in Japan. In the construction field of Japan, there is a CO2 concentration standard of a thousand ppm or less. However, property of occupants (such as sex, age and nationality) has non-nogligiblw effect on the room odor environment. Thus the standard of ventilation air volume should be decided suiting up for building use and occupants. In this research, we made the exposure experiments of human bioeffluents caused by occupants and considered the difference between the subjectively reports. Five conditions were set. The first one is “under twenty-five years old under uncontrolled condition” made up of people in the age of twenty-five and without restrictions on clothes and the use of cosmetics etc. The second one is “over thirty-five years old condition” made up of people in the age of thirty-five and the third one is “non-Japanese condition” made up of people with mainly Asian nationality except Japan. The fourth one is “minimum emission condition” made up of people in the age of twenty-five and with restrictions on clothes and the use of cosmetics to limit the body odor derived from pure human body. And the last one is “sweating condition” whose occupants do step up&down aerobics activity to sweat before the experiment. We made panel evaluate using three evaluation scales. Odor intensity, hedonic scale and acceptability. We called into account the influence of olfactory adaptation, so we prepared six occupant panel and six visitor panel separately. As an experimental procedure, we let the occupant panel enter a chamber and the CO2 concentration becomes five thousand ppm by controlling the ventilation rate. Panel evaluate multiple times during the ascent process of body odor and CO2. And in order to identify the components contained in the indoor air, we obtained samples at CO2 concentration of five thousand ppm and did quantitative analyses. And to increase the number of data, the evaluations were conducted three times with almost three minutes intervals. But the statistical reliability is unknown for the multiple evaluation by a small number like this time, so we needed to make a study about that. In particular, we developed a probabilistic prediction method based on normal distribution. As a result of experiments, we confirmed the influence of property of occupants on the subjective evaluation and the difference between evaluations of occupants and visitors. For example, in odor intensity, evaluation of occupants is almost flat throughout the experiment. On the other hand, visitors gained higher evaluation at CO2 concentration increased. And evaluation of occupants is more sensitive on “non-Japanese people condition” than other conditions. It seems that the occupants responded more sensitively to each other’s body odor because people with different nationalities existed in the same place.