Dimensional and chemical characterization of airborne particles in schools: Respiratory effects in children

This work reports the detailed characterization of child exposure to particles in three naturally-ventilated Italian schools. Two polluted urban schools and a rural one are considered in this study. Dimensional and chemical analyses of particles were performed by measuring particle number concentrations, particle size distributions, OC/BC concentrations and relative inorganic and organic fractions, both indoors and outdoors. Respiratory function, exhaled Nitric Oxide (eNO) and Prick Skin tests were also performed on 75 children attending the three schools in order to evaluate the effects of such exposure on the children's respiratory systems. Exposure to particles at the urban schools was found higher than at the rural one, from both dimensional and chemical perspectives. Indoor particle number concentrations ranged from 1.95 × 10^4 to 3.49 × 10^4 part./cm^3, whereas indoor black carbon concentrations varied between 1.9-13.9 μg/m^3, with the lowest levels of both measured at the rural school. In contrast to the dimensional and chemical results, the respiratory function and eNO test results were statistically similar among children attending all the three schools: the lung function values were within 20% of the European Community for Steel and Coal predicted ones, with the eNO data for healthy children ranging from 10.1 to 11.5 ppm. Medical outcomes indicate that these levels of school exposure did not significantly affect the children's respiratory outcomes.