Indoor and outdoor concentrations of benzene, toluene, ethylbenzene and xylene in some Italian schools evaluation of areas with different air pollution

The air quality of indoor environments is an aspect of great importance and of growing interest, particularly considering the length of time that people stay in confined spaces. The objective of this study was to study the indoor and outdoor concentrations of benzene, toluene, ethylbenzene and xylene (BTEX) in 8 Italian schools, many of which are located in some of the most highly polluted areas in Italy. This wanted to provide useful information for understanding the status of air quality in sensitive indoor and outdoor areas (schools) and to support the development of recommendations and indications useful to territorial administrations in the improvement of environmental quality strategies. The sampling campaigns were performed with passive samplers from 2014 to 2015, studying both the hot and cold seasons. A common sampling and analytical protocol was applied in all the study areas. Passive sampler data were also compared with BTEX measurements from fixed-site monitoring stations selected as references for each school. Our findings showed the prevalence of low BTEX concentrations with relatively high values limited to toluene, ethylbenzene and xylene in a few monitoring sites and periods. The mean concentration values of benzene, toluene, ethylbenzene and xylene varied from 0.10 μg/m3 to 10.75 μg/m3, from 0.10 μg/m3 to 28.18 μg/m3, from 0.10 μg/m3 to 11.1 μg/m3 and from 0.10 μg/m3 to 14.45 μg/m3, respectively. In indoor environments, the concentrations were equal to or higher than the values measured outdoors in most cases, frequently reporting I/O ratios greater than 1.