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.

为了评估位于首尔交通繁忙地区的小学中的细颗粒物水平并验证排放源，在不受控制的条件下对教室进行了现场研究。I / O比（基于质量浓度）为0.52-0.92，表明室内PM _2.5低于室外PM _2.5，并保持在国家准则以下。室内PM _2.5中的重金属，例如Cr，Mn，Ni，Cu，Zn，As，Sn和Pb低于室外。相反，室内PM _2.5中的OC和EC等碳含量较高。通过源分配分析，室外排放源占教室PM _2.5的58.5％。。这项研究可有助于城市规划和学校设计，以确保儿童免受有害环境的伤害。