A cross-sectional study of schools for compliance to ventilation rate requirements

The use of continuous data logging instruments recorded levels of carbon dioxide (CO2) exhaled by students in schools. This allowed a check of a large data set in order to determine ventilation rates from the rate of its decay (ΔCO2). Data collected on CO2 levels through time was a useful tool for determining the effect of mechanical equipment to ventilation rates as part of a larger study on indoor air quality. Calculation of the air exchange rate (AER) used ASTM tracer gas methods applied to a regression analysis where the data showed a logarithmic decay rate. Ventilation measured in this study was total ventilation including mechanical ventilation from heating ventilation and air conditioning (HVAC) units, replacement air from exhaust fans and infiltration through outside walls.