2017 No https://www.sciencedirect.com/science/article/abs/pii/S0013935116306090 Salin,, JT Europe Exposure Study Teachers Dust Bacteria Fungi Viruses Respiratory symptoms Vision Headaches Building-related symptoms Indoor dust Airborne toxicity Sperm motility Indoor toxicity The Poisson regression model showed that the impact of extracts of surface-wiped school classroom dust on teacher work-related BRS was 2.8-fold (95% CI: 1.6–4.9) higher in classrooms with a toxic threshold EC50 of 6 µg ml−1 versus classrooms with insignificant EC50 values (EC50 >50 µg ml−1); P<0.001. The number of symptoms that were alleviated during vacation was higher in school classrooms with high sperm toxicity compared to less toxic sites; the RR was 1.9 (95% CI: 1.1–3.3, P=0.03) for wiped dust extracts.