2019 Yes http://psasir.upm.edu.my/id/eprint/76439/1/2019121207382616_MJMHS_0413.pdf Pakpahan, Sasnila Asia Observational Epidemiology Study Exposure Study Students Middle/Jr High (6-8) Carbon Dioxide (CO2) Particulate Matter (PM) Volatile Organic Compounds (VOCs) Fine particulate matter (PM 2.5) Respirable particulate matter (PM 10) Carbon dioxide (CO2) Formaldehyde School health Air quality (PM₂.₅, PM₁₀, CO₂, HCHO) was assessed in 3 Indonesian junior high schools; PM exceeded safe levels, posing health risks. Policy implications include improved school air quality monitoring.