Validity of building characteristics and dorm dampness obtained in a self-administrated questionnaire

A self-administrated questionnaire used in a cross-sectional study on associations between environmental factors and allergies was validated by building inspections and physical measurements. The agreement was good between the reports from occupants and inspectors regarding technical characteristics, such as type of surface materials etc., but a poor to slight agreement (kappa < 0.2) regarding on assessments of moisture damages, such as mould or damp spots, and a mouldy smell, between occupants and inspectors. Dampness problems reported by occupants were associated with health effects (case status), while such problems observed by inspectors were not. The air relative humidity was slightly higher, during winter time, in rooms with condensation on windowpanes. The results indicate that questionnaire surveys give valid data regarding most technical characteristics. With regard to moisture damages, occupants reports seem more relevant than inspector reports, in a study of health.