In the 1990s, the so-called ‘sick house syndrome’ became an area of public concern. Consequently, the Ministry of Health, Labour and Welfare of Japan established Indoor Air Guidelines for 13 compounds as a preventive measure against sick house syndrome. In recent years, lower concentrations of the 13 chemicals in newly built houses diminished the health risk from those chemicals. As a result, instead of the regulated chemicals, unregulated chemicals such as methylcyclohexane, dichloromethane and acetone became common in building materials. These chemicals have also been found to cause sick house syndrome. Thus, in addition to the regulation of individual chemicals, it is now believed that it is necessary to minimize the total amount of volatile organic compounds (VOCs) in order to diminish the health risk from indoor air chemicals.
