2024 Yes Assessment of indoor air quality and risk of COVID-19 infection in Spanish secondary school and university classrooms https://www.sciencedirect.com/science/article/pii/S0360132322009477 Rodríguez, Diana Europe Exposure Modeling Middle/Jr High (6-8) High School (9-12) Carbon Dioxide (CO2) Particulate Matter (PM) Ozone (O3) Nitrogen Dioxide (NO2) Classrooms Ventilation Indoor air quality Hygrothermal comfort Airborne transmission COVID-19 infection risk Ventilation and indoor air quality in Spanish secondary and university classrooms were evaluated during COVID-19. Mechanical ventilation improved air quality and reduced transmission risk. Controlled ventilation and mask use are vital to limit airborne infections in schools. 2022