Odors in living environments are considered an essential factor related to air cleanliness and air quality. Since indoor air quality issues became more prominent in the 1990s, public awareness of indoor air quality has increased, leading to a growing number of people paying attention to odors in their living spaces. Additionally, there has been an increase in behaviors that actively incorporate fragrances into daily life. As a result, living spaces now contain not only unpleasant odors but also pleasant fragrances, making odors a key element of comfort.

This paper examines the impact of lifestyle changes on odors in living spaces and categorizes different types of unpleasant odors along with their main odorants. Furthermore, it discusses approaches to odor control in indoor environments and presents case studies on odor management in elderly care settings. Additionally, by referencing odor thresholds, the guideline values for indoor air concentration of individual chemicals established by the Ministry of Health, Labour and Welfare, and Architectural Institute of Japan Environmental Standards, Standard of Control and Maintenance of Indoor Odor (AIJES-A0003-2019), this study explores odor perception from both a health and comfort perspective.

The objective of this paper is to clarify the relationship between interior styles and the elements that compose them in residential interiors, and to obtain an index for determining styles that can be used by stakeholders involved in interiors. As a first step, an experiment was conducted in which interior experts judged the interior styles of circulating photographs of residential interiors, and to find out what elements characterize them. The experts performed impression evaluations, style judgments, and regional judgments on the photographed examples. Using the results of the impression evaluations, the examples were classified into six major classification and 11 sub-classification groups through cluster analysis. From the results of the style judgments, the major categories were identified as ‘Simple’, ‘Modern’, ‘Casual’, ‘Country’, ‘Natural’, and ‘Classic’. The explanatory elements that characterize these classification groups were identified, and it was determined that the names were reminiscent of the explanatory elements. Furthermore, to create an index that interprets the explanatory elements on a unified scale, the explanatory elements were aggregated using principal component analysis, and two indices, “urbanity-naturalness” and “everydayness-style,” were derived. The two indices allowed for a quantitative judgment of the major classification groups. Using this relationship, it was possible to achieve a common understanding of interior design between interior design professionals and clients.

This study focuses on “olfactory adaptation,” investigating the decrease in sensory intensity due to continuous exposure to the same odor stimulus. The study investigates the alleviation of unpleasant odor perception in panels after exposing them to a high concentration of skatole, which alters its odor quality depending on concentration, following adaptation to a non-unpleasant low concentration.Odor quality evaluations of high-concentration skatole (odor concentration of 100) were compared between two conditions: an “adaptation” condition, where subjects were exposed to low-concentration skatole (odor concentration of 2) for one minute to induce olfactory adaptation, and a “non-adaptation” condition with normal olfactory sensitivity. The results indicate that, comparing the evaluations of high-concentration skatole between the adaptation and non-adaptation conditions, adaptation results in decreased odor intensity, reduced unpleasantness, and a lower percentage of unacceptable ratings. Despite exposure to the same odor, the pattern similarity rate based on mean value profiles using the Semantic Differential (SD) method was 0.929 between the two groups, indicating that the participants do not perceive it as the same odor. Furthermore, the odor quality evaluation in the adaptation condition felt more “refreshing” compared to that in the non-adaptation condition, indicating that olfactory adaptation induced by low-concentration skatole mitigated unpleasant odor sensations at high concentrations.