Individuals living in of about 1 percent of newly built or recently renovated homes in Japan suffer symptoms of sick building syndrome, and high humidity probably increases the risk, the health ministry said Monday.
The estimate is based on a ministry survey deemed the first comprehensive nationwide research on the mysterious syndrome and its correlation with living environments.
The suspected cause of sick building syndrome is an "increase in allergen because of mold and mildew, and chemical substances dissolved from building materials," said Hokkaido University graduate school professor Reiko Kishi, who led the survey.
Kishi said it is possible to improve conditions through appropriate humidity control.
In the survey, which drew responses from some 2,300 households in six cities across the country, the ministry panel defined sick building syndrome as a condition in which someone regularly suffers symptoms including headaches and itchiness in the eyes and nose and such symptoms improve when a sufferer leaves home.