2024 Yes The effect of the shoeless course on particle concentrations and dust composition in schools https://www.sciencedirect.com/science/article/abs/pii/S0048969719362680?via%3Dihub Leppänen, Maija Europe Experimental Exposure Elementary (K-5) Particulate Matter (PM) Indoor air quality Aerosol respirable particulate matter (PM10) Elemental analysis Finnish study compared particle levels in schools where shoes were removed at entry vs. near classrooms. PM10 and PM15 were lower in sock schools, suggesting that early shoe removal can reduce indoor dust and improve school air quality. 2020