Indoor climate and moisture problems in Finnish schools.

The purpose of the study was to assess actual ventilation, indoor air quality and also the quality of repairing process in the Finnish schools. The measurements that included ventilation rate, co2 and particle concentrations, and temperature and humidity in the classrooms were carried out in 20 schools. Repairing of schools were studied on the basis of 32 schools. The typical needs for repairing HY AC-systems and building structures and also typical repairing measures and faults were reported. The most common problem was the classrooms' old-fashioned or even missing ventilation devices. The type of ventilation system had a significant influence on the quality of indoor air and on the occurrence of problems. The air change rates were higher and, C02 concentrations and occurrence of draught were remarkably lower in mechanical supply and exhaust ventilation compared to natural ventilation and mechanical exhaust ventilation systems. In general the problems, connected to the ventilation system, were more common than water damage and mold problems. The average concentration of particles was measured in the winter 0, 14 mg/ml and in the autumn 0,07 mg/ml. It is remarkable that the concentration of respirable particles was higher in the autumn when the total concentration of particles was lower than in the winter.