Titanium dioxide nanoparticles : occupational exposure assessment in the photocatalytic paving production

Limited data are available regarding occupational exposure assessment to nano-sized titanium dioxide (nano-TiO2). The objective of this study is to assess the occupational exposure of workers engaged in the application of nano-TiO2 onto concrete building materials, by means of a multi-metric approach (mean diameter, number, mass and surface area concentrations). The measurement design consists of the combined use of (i) direct-reading instruments to evaluate the total particle number concentrations relative to the background concentration and the mean size-dependent characteristics of particles (mean diameter and surface area concentration) and to estimate the 8-h time-weighted average (8-h TWA) exposure to nano-TiO2 for workers involved in different working tasks; and (ii) filter-based air sampling, used for the determination of size-resolved particle mass concentrations. A further estimation was performed to obtain the mean 8-h TWA exposure values expressed as mass concentrations (\ub5g nano-TiO2/m3). The multi-metric characterization of occupational exposure to nano-TiO2 was significantly different both for different work environments and for each work task. Generally, workers were exposed to engineered nanoparticles (ENPs;