2024 No Risk of illness-related school absenteeism for elementary students with exposure to PM2.5 and O3 https://doi.org/10.1016/j.scitotenv.2022.156824 Zhang, Ting Asia Epidemiological Observational Students Elementary (K-5) Particulate Matter (PM) Ozone (O3) Absenteeism Fine particulate matter Ozone Children's health Illness-related school absenteeism Hospital visit record Analyzed 687,748 illness-related absences from 2,564 Chinese elementary schools. PM2.5 and O₃ exposure increased risk of absence, with home care cases undercounted in hospital data. Supports pollution control and school-based illness tracking. 2022