Characterization and source identification of fine dust in Seoul elementary school classrooms

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 PM_2.5 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 PM_2.5 than outdoors. On the contrary, carbons including OC and EC were higher in indoor PM_2.5. As a result of source apportionment analysis, an outdoor emission source was responsible for 58.5% of the classroom PM_2.5. This study can contribute to urban planning and school design to keep children safe from harmful environments.