The vertical temperature difference and CO₂ concentration were measured an elementary school classrooms without ventilation equipment. In a first graders’ classrooms, the vertical temperature difference was observed significantly during winter period. On the other hand, typical temperature vertical difference was not obtained in a six graders’ classroom. The 5 percentile value of the estimated ventilation rate per person determined from CO2 concentration was less than 30 ㎥/h during winter.
