2024 Yes Effectiveness of a Protocol to Reduce Children’s Exposure to Particulate Matter and NO2 in Schools during Alert Days https://www.mdpi.com/1660-4601/19/17/11019 Zauli-Sajani, Stefano Europe Exposure Elementary (K-5) Particulate Matter (PM) Temperature Humidity Schools Indoor air quality Prevention particulate matter severe air pollution episodes A classroom protocol using window ventilation and air purifiers on PM₁₀ alert days reduced indoor/outdoor pollutant ratios in a polluted area of Italy. PM₁₀ levels dropped without raising CO₂. Findings support exposure reduction during pollution episodes. 2022