2021 No https://doi.org/10.1016/j.scitotenv.2021.147498 Kabirikopaei, Adel North America Observational Exposure Study Modeling Students Elementary (K-5) Middle/Jr High (6-8) High School (9-12) Carbon Dioxide (CO2) Carbon Monoxide (CO) Particulate Matter (PM) Volatile Organic Compounds (VOCs) Ozone (O3) Nitrogen Dioxide (NO2) Test performance Indoor air quality Academic performance Classrooms Student demographics IAQ factors and student test scores were analyzed in 220 U.S. classrooms across seasons. Fine particles, ozone, CO, and ventilation type were linked to academic outcomes. Findings support HVAC upgrades for better learning environments.