Indoor Air Quality in Tehran’s Primary Schools: Seasonal Variations and Impact of External Pollution Sources on Pollutant Concentrations—A Comprehensive Analytical Study

The children’s sensitivity to high concentrations of pollutants in schools has led to increased attention to indoor air quality in recent years. Hence, the study was aimed at determining the concentration of air pollutants in primary school classrooms in Tehran during one academic year. For this purpose, the research team identified and evaluated primary schools in different regions of the Tehran megacity. Schools with similar characteristics were selected to sample CO₂, PM₁, PM_2.5, and PM₁₀ pollutants in the indoor air of Tehran primary school classrooms. A total of 30 classrooms were sampled in five schools during the autumn, winter, and spring seasons of one academic year, spanning from September 2016 to May 2017. Data analysis was conducted using Python-based tools, including Seaborn and Matplotlib, to generate visual insights. The results showed that the concentration of the pollutants studied differs significantly in winter compared to autumn and spring in the indoor air of the classrooms. The highest CO₂, PM₁, PM_2.5, PM₁₀, and PM_Total concentrations were observed in the north, center, south, south, and south of Tehran, especially in the ground-floor classrooms, respectively. The results of distance from green space, private space, and floors in winter emphasize an internal source of pollution; conversely, in spring and autumn, they show the influence of external sources on the concentration of pollutants inside the classrooms in various areas of Tehran. To summarize, the results of this study showed that the indoor air quality of primary school classrooms in Tehran requires careful investigation and urgent measures to reduce pollutants and improve environmental conditions to maintain the health and comfort of students and school board members.