2024 No Characterization and source identification of fine dust in Seoul elementary school classrooms https://www.sciencedirect.com/science/article/abs/pii/S0304389421004945 Heo, Sujeong Asia Experimental Elementary (K-5) Dust School air quality Particulate matter (PM) fine particulate matter (PM2.5) Emission source Chemical constituent In high-traffic Seoul schools, indoor PM2.5 was lower than outdoors, though carbon levels were higher indoors. Source analysis showed 58.5% of indoor PM2.5 came from outside. Findings inform urban planning to reduce school air pollution exposure. 2021