2022 Yes https://www.sciencedirect.com/science/article/pii/S004896972106099X?via%3Dihub Faria, T. Europe Exposure Study Elementary (K-5) Particulate Matter (PM) Exposure Dose assessment particulate matter Mass closure Air quality Results indicated that the high contribution of particulate organic matter (POM) indoors indicate high contributions of indoor sources to the organic fraction of the particles. The highest concentrations of PM chemical compounds and the highest Indoor/Outdoor ratios were measured in schools, where the contribution of mineral elements stands out due to the resuspension of dust caused by the students and to the chalk used in blackboards. The contribution of the outdoor particles to inhaled dose (24%) was higher than to the exposure (12%), due to the highest inhalation rates associated with the activities performed outdoor. This study indicates the importance of indoor air quality for the children's exposure and health.