Correlation between carbonaceous materials and fine particulate matters in urban school classrooms

Abstract

Airborne carbonaceous substances in the school classroom cause an adverse effect on young children. This study attempted to find a correlation between carbons and fine particulate matters in 24 urban schools, focusing on class hours during which students can be exposed. Sampling and measurement of particulate pollutants were carried out without intentional control of classroom conditions to assess general indoor air quality. Statistical evaluation of the entire dataset showed that the average PM_2.5 and PM₁₀ concentrations in classrooms (22.7 μg/m³ and 43.3 μg/m³) were lower than outdoors (34.0 μg/m³ and 54.3 μg/m³) on a gravimetric basis. Organic carbons in the classroom were 13.7 times higher than elemental carbons. Indoor black carbon (mainly introduced from outside), of which mean concentration monitored in real-time was1.04 μg/m³, showed a high correlation coefficient (0.755) with 0.6 μm. Schools adjacent to large roads with high traffic were more vulnerable to black carbon exposure (1.3 to 2.2 μg/m³) than residential areas (0.3 to 0.8 μg/m³). Thus, careful environmental considerations are needed when managing indoor pollution and building new schools, particularly in developing and populated countries.