Effects on health related symptoms of carpet removal and ventilation improvement in eleven schools - a controlled intervention study

An intervention study was carried out in eleven elementary schools in Trondheim, Norway. Three schools with poor ventilation standard, four schools with carpets, and four reference schools participated. Carpets were replaced by vinyl flooring and the poor ventilation systems were upgraded. Altogether 1100 children aged twelve to thirteen years and 400 teachers were all included in the study. The baseline registration of health related symptoms was performed during January/February 1997. The questionnaires were repeated, after the interventions, in February 1998 and 1999. The questionnaire used corresponds to questions in the rebro questionnaire, but was adjusted to be performed with three repetitions during two weeks. In addition, a questionnaire on symptoms and asthma management to identify hypersensitive children was used in 1998 and 1999. Compared to reference schools the results from the intervention schools showed that the number of health related symptoms were reduced for both children with and without hypersensitivity.