Ventilation Rates in Schools and Learning Performance Zs. Bakó-Biró 1 , N. Kochhar 1 , D.J. Clements-Croome 1 , H.B. Awbi 1 and M. Williams 2 1 School of Construction Management and Engineering, The University of Reading, Whiteknights, PO Box 219, RG6 6AW Reading, United Kingdom 2 School of Psychology and Clinical Language Sciences, The University of Reading, Harry Pitt Building, Earley Gate, RG6 6AL Reading, United Kingdom Corresponding email: z.bakobiro@reading.ac.uk SUMMARY Associations between classroom ventilation and pupils’ performance were investigated in primary schools in the United Kingdom. The concentration of carbon dioxide and other parameters were monitored for three weeks in two selected classrooms in each school. A direct air supply system through the windows was used to alter the ventilation rates in the classrooms. The system was set either to provide outdoor air or to re-circulate the classroom air while all other physical parameters were left unchanged. Computerised Assessment Tests and Paper-based Tasks were used to evaluate pupils’ performance. Pupils’ perceptions about the classroom environment, comfort, general mood and hunger were assessed on subjective scales. The present paper shows preliminary results obtained for one primary school out of eight being studied. Due to the intervention the fresh air supply increased from 0.3-05 to 13- 16 L/s per person that increased pupils’ work rate by ~7% in addition (p<0.036) and subtraction (p<0.052). INTRODUCTION Former reviews on the subject of school environments emphasised that ventilation is often inadequate in classrooms causing increased risk for asthma and other health-related symptoms among school children [1], [2]. Mendell & Heath [2] proposed that throughout the life of each existing and future school building immediate measures should be taken for the provision of adequate outdoor ventilation, control of moisture, and avoidance of indoor exposures to microbiologic and chemical substances considered likely to have adverse effects. The current ventilation standards and guidelines [3], [4] recommend a minimum fresh air supply rate of 8 litres/s per person for occupants in all teaching facilities. The recently published Building Bulletin 101 refers to proposed performance based standards limiting the level of carbon dioxide (CO 2 ) concentration to 1500 ppm over a full school day from 9:00 to 15:30 and specifies a minimum supply of external air at least 3 L/s per person in all teaching and learning spaces when they are occupied. Furthermore, a ventilation rate of 8 L/s per person for the normal number of occupants should be achievable under the control of occupants, although it may not be required at all times if occupancy level decreases. However, according to recent studies the average CO 2 levels in classrooms often exceed the above limit and ventilation rates are often below the minimum requirement of 3 L/s per person [5], [6]. The negative effects of poor ventilation rates on work performance in office buildings have been widely investigated [7]. Knowing the outcome of poor ventilation rates for the adult population it could be expected that not only the comfort and health, but also the learning performance of school children are affected by the poor environmental conditions in classrooms [2]. Following the earlier studies suggesting correlation between pupils’ health Proceedings of Clima 2007 WellBeing Indoors