Study on the Classroom AIr Environment in Elementary and Secondary Schools in Ward X of the Tokyo Before and After the Covid‑19 Pandemic Using Administrative Data

Using the results of air environment measurements from school environmental hygiene inspections conducted in Ward X of Tokyo, we analyzed long-term changes in CO2 concentration, indoor temperature, and the opening length of windows and doors. Before the outbreak of COVID-19 in 2020, the 95th percentile of indoor CO2 concentrations in elementary and junior high school classrooms during winter and summer was approximately 2000–2500 ppm, exceeding the school environmental hygiene standard of 1500 ppm. After 2020, the 95th percentile decreased to below 1500 ppm.