2020 Yes https://doi.org/10.1016/j.scitotenv.2020.138360 Kumar, Prashant Europe Experimental Exposure Study Students Elementary (K-5) Carbon Dioxide (CO2) Particulate Matter (PM) Other Citizen science Smart citizen kits Community engagement Air pollution exposure A co-designed citizen science project with a primary school used smart sensor kits to monitor PM2.5 and CO₂ across drop-off, pick-up, and off-peak hours. Fine particulate levels peaked during car drop-off. Results inform strategies to alter commuting habits and improve school air quality.