Perceived dryness in houses and adverse health effects during winter in Japan

Abstract

In recent years, as houses have become more insulated and airtight, indoor environments in Japan have tended to become low-humidity in winter, making dryness a problem. The relationship between the perception of dryness indoors and low indoor humidity is unclear, though it has been suggested that other environmental factors may influence perception of dryness and adverse health effects. It is essential to clarify the association between the indoor environment and human responses related to the perception of dryness. A questionnaire survey regarding indoor thermal environment, air quality, living environment, resident characteristics, resident behaviour, and health-related symptoms was conducted throughout Japan in the winter of 2022. The paper first describes the findings of this survey on resident characteristics, building characteristics, indoor humidity sensation, operating patterns of humidifiers and other devices, and resident health problems related to indoor dryness. Next, multiple regression analysis was used to identify the factors influencing the impact of dryness on health problems at various sites.