2024 Yes Description of air quality and environmental characteristics in primary school classrooms in the Community of Madrid https://doi.org/10.1016/j.anpedi.2025.503792 Pérez-Moneo, Begoña Europe Observational Exposure Students Staff Elementary (K-5) Particulate Matter (PM) Volatile Organic Compounds (VOCs) Carbon Dioxide (CO2) Temperature Humidity Child Schools Indoor air quality particulate matter A longitudinal study measured PM2.5, CO2, VOCs, temperature, and humidity in four Madrid schools. PM2.5 and VOCs exceeded thresholds in a large share of samples, underscoring the need for improved indoor air quality management in schools. 2025