The effect of the shoeless course on particle concentrations and dust composition in schools

Airborne particles may effect on indoor air quality in schools. One significant particle source is outdoor dust and soil transported indoors on people's shoes, which may be resuspended, and further inhaled by pupils and teachers. In many Finnish schools, shoes are taken off by coat racks near the classrooms (shoe schools). The new course of action is to take shoes off right when entering the building (sock schools). In this study, particle mass and number concentrations, together with chemical composition of the dust were investigated in sock and shoe schools. According to results, PM₁₀ and PM₁₅ concentrations in corridors were significantly higher in shoe schools compared to sock schools (p < 0.05). The shoeless course did not affect on the particle number concentrations, but the increases in the number concentrations originated from diners. The elemental concentrations (Li, Al, Si, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Ba, Pb) in settled dust were also higher in shoe schools compared to sock schools, and the Zn concentrations differed significantly (p < 0.05). In conclusion, this study showed that by taking the shoes off when entering the school building you can enhance the indoor air quality by reducing the particle mass concentrations.