2024 Yes Diurnal variation and potential sources of indoor formaldehyde at elementary school, high school and university in the Centre Val de Loire region of France https://www.sciencedirect.com/science/article/pii/S0048969721073472?via%3Dihub Hu, Dawei Europe Exposure Students Elementary (K-5) Middle/Jr High (6-8) High School (9-12) Volatile Organic Compounds (VOCs) Indoor air quality Formaldehyde School classrooms Seasons Formaldehyde levels in French schools ranged 11-18 μg/m³, below WHO limits. Ventilation reduced levels by 25-38%. Tobacco smoke and cleaning products increased formaldehyde via secondary emissions. Controlling these sources is key to reducing indoor exposure. 2022