Indoor air quality investigation of the school environment and estimated health risks: Two-season measurements in primary schools in Kozani, Greece

Results indicated that indoor air concentrations of the measured pollutants were within accepted limits with indicative ranges 1.5-9.4 μg/m3 for benzene, 2.3-28.5 μg/m3 for formaldehyde, 4.6-43 μg/m3 for NO2 and 0.1-15.6 μg/m3 for O3. Emissions from building materials seem to have a significant contribution to the indoor air quality. Very low ventilation rates (0.1-3.7 L/s per person) were observed, indicating inadequate ventilation and possible indoor air quality problems requiring intervention measures. The estimated average lifetime cancer risks for benzene, formaldehyde and trichloroethylene were very low.