Abstract
In order to clarify IAQ problem of detached houses located in cold climatic region, particularly well-insulated airtight houses, measurements were conducted in the winter since 2001. The formaldehyde concentrations in most houses were found to be lower than 100μg/m^3, but the TVOC concentrations in most houses including a conventional house that has low insulation and airtightness without mechanical ventilation system were higher than 400μg/m^3. Materials used in daily life as well as building materials might lead to emission of VOCs. It was suggested IAQ problem in cold climatic region would be serious in not only well-insulated houses but also ordinary houses.
