Indoor air pollution with benzene, formaldehyde, and nitrogen dioxide in schools in Osijek, Croatia

Exposure to air pollution and poor indoor air quality is associated with a variety of adverse health outcomes, especially in schoolchildren. This paper presents results of the pilot study of the formaldehyde, benzene, and nitrogen dioxide measurements in classrooms and at outdoor sites in two schools in Osijek, Croatia, carried out by the Institute of Public Health for the Osijek-Baranya County and WHO. Concentrations of formaldehyde and nitrogen dioxide in classrooms (formaldehyde average weekly concentration = 8.48 μg/m 3 , SD = 2.33; NO 2 average weekly concentration = 11.12 μg/m 3 , SD = 2.49) were below the WHO guideline values for indoor air. The concentration of benzene in indoor air in one school (0.44 μg/m 3 ) was similar to the level of this chemical in ambient air (0.65 μg/m 3 ) while the data for another school (1.63 μg/m 3 ) suggested the presence of indoor sources of benzene. The highest concentration of formaldehyde was observed in a room where mold, dampness, and condensation contamination were visible. School power plants and road traffic affected higher values of indoor air NO 2 concentration.