2022 Yes https://www.sciencedirect.com/science/article/pii/S143846392100225X Miranda, M.T. Europe Observational Exposure Study Ventilation rates Temperature Humidity Carbon Dioxide (CO2) Ventilation Thermal comfort Carbon dioxide (CO2) Ventilation rate Indoor air quality As the main results of the study, ventilation conditions were generally adequate in all the tests carried out, regardless of the ventilation strategy used, with average CO2 concentration levels of between 450 and 670 ppm. The maximum CO2 concentration value recorded in one of the tests was 808 ppm. On this basis, the limit for category IDA 2 buildings, corresponding to educational establishments, was not exceeded in any case. However, these measures affected the thermal comfort of the occupants, especially when the outside temperature was below 6 °C, with a dissatisfaction rate of between 25 and 72%. Examinations carried out with outside temperatures above 12 °C were conducted in acceptable comfort conditions regardless of outside air supply and classroom occupancy. In these cases, the dissatisfaction rate was less than 10%. The results obtained have made it possible to establish strategies for ventilation in the implementation of future exams, depending on the climatic conditions outside.