2024 Yes Evaluation of Low-Cost Mitigation Measures Implemented to Improve Air Quality in Nursery and Primary Schools https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5486271/ Sá, Juliana P. Europe Review Elementary (K-5) Carbon Dioxide (CO2) Particulate Matter (PM) Volatile Organic Compounds (VOCs) Indoor air Mitigation measures evaluation Nursery schools Primary schools Air pollutants were monitored before and after low-cost mitigation in nursery and primary schools. CO₂ levels improved post-intervention, but PM and formaldehyde often exceeded health guidelines, indicating further actions are needed. 2017