Background: Little previous research has analysed the relationship between schools' indoor air problems and schools' social climate. In this study, we analysed a) whether observed mould and dampness in a school building relates to students' perceptions of school climate (i.e. teacher-student relationships and class spirit) and b) whether reported subjective indoor air quality (IAQ) at the school level mediates this relationship.
Methods: The data analysed was created by merging two nationwide data sets: survey data from students, including information on subjective IAQ (N = 25,101 students), and data from schools, including information on mould and dampness in school buildings (N = 222). The data was analysed using multilevel mediational models.
Results: After the background variables were adjusted, schools' observed mould and dampness was not significantly related to neither student-perceived teacher-student relationships nor class spirit. However, our mediational models showed that there were significant indirect effects from schools' observed mould and dampness to outcome variables via school-level subjective IAQ: a) in schools with mould and dampness, students reported significantly poorer subjective IAQ (standardised β = 0.34, p < 0.001) than in schools without; b) the worse the subjective IAQ at school level, the worse the student-reported teacher-student relationships (β = 0.31, p = 0.001) and class spirit (β = 0.25, p = 0.006).
Conclusions: Problems in a school's indoor environment may impair the school's social climate to the degree that such problems decrease the school's perceived IAQ.
Keywords: Class spirit; Dampness; Indoor air quality; Indoor environmental problems; Mould; Multilevel analysis; Teacher-student relationships.