Relation between ventilation and the learning skills of pupils in classrooms.

Goal of the study was to investigate the relation betweenthe level of ventilation and the performance of school children in classroomsIn one school in two classrooms the same ventilation system was installed. The two classrooms were located at the same faade. The system had a possibility of supplyingfull outside air to the classroom or the position with full recirculation of air. The temperature in the classroom was kept as constant as possible.The performance of two groups in the age of about 12 years was studied.The pupils had to carry out four different tests: comparing symbols the position of the legs of the clock spelling language calculationThe weeks before the real test the pupils already had carried out the same type of test to overcome the effect of adaptation to these type of tests.The average CO2 concentration at the beginning of the tests was approximately: conditioned classroom 738 ppm unconditioned classroom 1267 ppmThe average CO2 concentration at the end of the tests was approximately: conditioned classroom 747 ppm unconditioned classroom 1870 ppmThe results of the tests are roughly that no significant effect was found for the more visual related tests such as comparing symbols and the legs of the clock. For the more cognitive tasks such as spelling and calculationsignificant effects were found. The improvement in relative score for the tests made under CO2 controlled conditions was in the order of about 15%.