Association of toxic indoor air with multi-organ symptoms in pupils attending a moisture-damaged school in Finland

Abstract

Background: There is an on-going debate on how best to test toxic indoor air. Toxicological methods based on condensed water samples and cell culture technique are newly introduced research tools which were tested in this study. Methods: Pupils (n=47) from a water-damaged and (n=56) healthy schools were interviewed using a questionnaire. Indoor air was collected with a novel condensed water sampling technique and human THP-1 macrophages were exposed to the condensate. The cytotoxicity of cotton wool swab samples was tested using human BJ fibroblasts. Conventional microbiological culture methods were also performed. Results: Gastrointestinal problems (GI) were reported by 51% from the study cohort but only 4% of the control cohort, relative risk RR=14.30. For any neurological or neuropsychological symptoms, the RR was 63.04, muscular-skeletal pain RR=58.28, headache RR=31.00, respiratory symptoms RR=22.64, fatigue RR=21.45, sub febrility RR=15.49, ear infections RR=7.74, skin rash RR=5.96, all being statistically significant (P<0.001). All indoor air (n=7) and cotton wool samples (n=2) taken from the water-damaged classroom or in proximity of the problematic classrooms were toxic in cell culture assays. Low numbers of moisture-damage indicators were recovered from wall, passive air, and swab samples, namely Aspergillus ochraceus species group, Aspergillus, Eurotium species group, Fusarium, Tritirachium, Scopulariopsis genus group and Aspergillus versicolores species group. Conclusions: Indoor air toxicity and dampness-related microbiota recovered from the classrooms were associated with multi-organ morbidity of the school occupants. These results corroborated our previous reports from two adult cohorts i.e. evidence of causality. These new toxicological methods based on condensed water and cell culturing techniques seem to be superior to conventional microbiological methods in correlating with clinical symptoms.