Performances of the Radiello® diffusive sampler for BTEX measurements: Influence of environmental conditions and determination of modelled sampling rates

Radiello® diffusive samplers filled with a thermally desorbable adsorbent (graphitised carbon Carbograph 4) have been evaluated for the monitoring of BTEX according to the European standard EN 13528-2. Blank values and analytical recovery rates were in agreement with the requirements of this protocol. The sampling rates have been estimated under various controlled atmospheres in order to evaluate the effects of some environmental factors on the performances of the Radiello® sampler: concentration levels, temperature, exposure time, humidity and wind velocity. The effects of back diffusion and a mixture of 37 VOC have been determined. According to the whole of these results, modelled sampling rates have been set up. These experiments in exposure chamber showed that, for a medium level of concentration in air (5 μg m−3 for benzene), the expanded uncertainties were between 20% for benzene and 27% for m/p-xylene under environmental indoor conditions and between 19% for benzene and 31% for m/p-xylene under environmental outdoor conditions. The result for benzene is conform to the requirements of the future European Directive for benzene which define the maximum of uncertainty to 25% for annual concentrations near 5 μg m−3.