Classroom air quality and pupil attendance and attainment in Aberdeen primary schools

Abstract

Background and Aims. In addition to indoor pollutant exposures at home, children are also exposed to many of the same pollutants at school and these have been linked to health outcomes. Few studies from the USA and Europe have reported association between reduced ventilation and poorer educational attainment. However, relatively a paucity of information is available to quantify the association in primary school in UK. At this backdrop, we test the hypothesis that classroom carbon dioxide concentration, as an indicator of ventilation rates are inversely related to child school attendance and educational attainment in a cross-sectional study. Methods. Ventilation rates were derived from concentrations of CO2 which were measured over a 3-5 day period in classrooms of children aged 6-7 and 10-11 years. Ventilation rates were related to the class average annual attendance and proportions attaining a national standard for reading, writing and numeracy. Results. Ventilation rates were calculated for 60 naturally ventilated classrooms. The median (interquartile range, IQR) ventilation rate was 7.1l/s/person (5.4, 9.6) and median (IQR) CO2 concentration averaged over the school day was 1122ppm (592-2115). There were positive correlations between classroom ventilation and attendance (rho 0.491 p<0.001) and reading attainment (rho 0.271, p=0.037) but not writing or numeracy. When socioeconomic factors were considered, attendance rose by an average of 0.18% [95% CI 0.06, 0.30] for each l/s/person increase in classroom ventilation. Conclusion. These results provide support for clear association between elevated level of classroom CO2 concentrations and reduced school attendance and reading score. What is unclear is whether poor ventilation directly affects attendance and cognitive ability or is simply a marker for increases in other indoor air pollutants which may produce these effects. There is a need for an intervention study to examine the benefits of increased classroom ventilation in schools.