2024 No Impact of indoor air pollution in nursery and primary schools onchildhood asthma https://www.sciencedirect.com/science/article/abs/pii/S0048969720345113?via%3Dihub Branco, Pedro Europe Observational Students Elementary (K-5) Carbon Dioxide (CO2) Carbon Monoxide (CO) Particulate Matter (PM) Volatile Organic Compounds (VOCs) Ozone (O3) Nitrogen Dioxide (NO2) Respiratory symptoms children Exposure Inhaled dose Indoor air School Asthma In 1,530 Portuguese children, indoor air pollution showed no direct link to asthma prevalence, but higher NO2, O3, and PM2.5 were associated with wheezing and lung function reduction. Sensitized children had increased asthma risk with particulate exposure, urging mitigation. 2020