Studying the efficiency of air cleaners at removing various indoor air impurities in classrooms and the relation to pupils’ symptoms
Hanna Leppänen, Annika Viljamaa, Martin Täubel, Anni-Mari Pulkkinen, Arto Pennanen, Tarja Yli-Tuomi, Timo Lanki, Taina Siponen, Raimo O. Salonen and Anne Hyvärinen