RESUMO
To evaluate the level of fine particulate matters in elementary schools located in a high traffic area of Seoul and verify the emission source, a field study on the classrooms was conducted under the uncontrolled condition. The indoor PM2.5 was lower than that of the outdoors as indicated by an I/O ratio of 0.52-0.92 based on mass concentration, and it was maintained below the National Guideline. Heavy metals such as Cr, Mn, Ni, Cu, Zn, As, Sn and Pb were lower in indoor PM2.5 than outdoors. On the contrary, carbons including OC and EC were higher in indoor PM2.5. As a result of source apportionment analysis, an outdoor emission source was responsible for 58.5% of the classroom PM2.5. This study can contribute to urban planning and school design to keep children safe from harmful environments.