In order to clarify the association between indoor environmental factors and child health problems, epidemiological type surveys for 4th and 5th grade primary school children have been carried out all over Japan. These surveys consist of three Phases including in questionnaire survey and field measurement, and each phase has been proceeded. The 2nd phase is a detailed questionnaire survey to investigate housing characteristics and health problems. From the results of questionnaire survey, it was found that dampness indicator such as condensation and visible mould growth strongly influenced on respiratory symptoms. In this paper, relationship between dampness indicators and indoor environmental factors was analysed statistically for clarifying housing characteristics of damp building affecting children's allergic symptoms. The analysed results are expected to show significant factors which could affect symptoms through the medium of dampness and possible preventions for dampness. Using an unvented heater and a laundry in indoor were defined as the strong factor to dampness indicators due to inadequate ventilation for dehumidification. It is important to keep the ventilation system operating in whole day.
