Key factors determining indoor air PM10 concentrations in naturally ventilated primary schools in Belgrade, Serbia

Indoor air quality (IAQ) is rated as a serious public health issue. Knowing children are accounted as more vulnerable to environmental health hazards, data are needed on air quality in schools. Methods A project was conducted from 2007 until 2009 (SEARCH, School Environment and Respiratory Health of Children), aiming to verify links between IAQ and children’s respiratory health. Study was conducted in ten primary schools on 735 children, in 44 classrooms. Children were randomly selected. Research tools and indicators used for children’s exposure to school environment were indoor and outdoor pollutants, two standardized questionnaires for school and classroom characteristics. In both classroom air and ambient air in front of them we measured, during a 5-day exposure period for continuous 24h measuring: carbon monoxide, carbon dioxide, indoor air temperature, relative humidity, and PM[10] during classes. Results PM[10] concentrations were significantly most frequent in an interval of ≥80.1μg/m[3], that is, in the interval above 50μg/m[3]. Mean PM[10] value was 82.24±42.43 μg/m[3], ranging from 32.00μg/m[3] to of 197.00μg/m[3]. Conclusion The increase of outdoor PM[10] concentration significantly affects the increase of indoor PM[10]. A statistically significant difference exists for average IAQ PM[10] concentrations vs. indicators of indoor thermal comfort zone (p