Abstract

To determine the main pollutants influencing classroom environments and examine their relationships with ventilation effectiveness, student density, and school location characteristics, this study was carried out to assess the IAQ in primary schools in Baghdad's Al-Karkh district. To reflect a range of building ages, structural designs, and levels of exposure to nearby traffic, twelve elementary schools were chosen at random. Calibrated portable instruments were used to measure the concentrations of carbon dioxide (CO₂), carbon monoxide (CO), fine particulate matter (PM₂.₅), inhalable particulate matter (PM₁₀), total volatile organic compounds (TVOCs), temperature, and relative humidity within the classrooms during the wet season of 2025 (the first academic semester). The findings revealed that numerous schools had pollution levels beyond the international recommended standards. PM₂.₅ varied from 24 to 95 μg/m³, PM₁₀ varied from up to 191 μg/m³, TVOCs varied from 442 to 521 μg/m³, and CO₂ concentrations varied from 1,000 to 1,525 ppm. On the other hand, in rooms with inadequate ventilation, the CO concentrations were near the threshold levels but remained within tolerable bounds (1.5–6 ppm). During the cooler months, the mean inside temperature was approximately 19 °C, which was marginally warmer than the outdoor readings. The relative humidity averaged 67%, which indicated limited air exchange and the buildup of pollutants. These results offer compelling evidence that inadequate ventilation exacerbates indoor air deterioration in classrooms, especially when paired with outside traffic pollutants and poor thermal-humidity conditions. To safeguard children's respiratory health and to create safer and healthier learning environments in Baghdad's schools, this study concludes that improved ventilation techniques, regular IAQ monitoring programs, and the application of sustainable preventive measures are crucial.