The possible release of engineered nanomaterials was investigated based on a previously developed but now refined methodology. Data from altogether eight industrial work areas in production plants of nanostructured TiO2 and Al2O3 particles were obtained and used to test the methodology and to derive a first assessment of possible exposure of workers. Particle size distributions were determined in work area environments with concurrent measurements at a comparison site. Data from the comparison site were used to estimate the particle background level in the work area and distinguish it from potentially released nanomaterial. The analysis is based on the comparison of time resolved data from the work area and the comparison site as well as data determined during periods with and without work activities in the work area. The data analysis method introduced delivers size-resolved information on the potential nanoparticle exposure of workers.
A significant release of particles in the size range 100–562 nm was observed in the work area of bagging aluminum oxide and is stemming from damaging or overfilling of bags, and the necessary activities during the cleaning of the work area. The maximum particle diameter of these particles was around 340 nm. At all other investigated locations no significant releases of particles in the size range 100–562 nm were determined. Also, no significant release of particles < 100 nm was observed in all work areas.
The average PM10 exposure during the work activities varied from 48 to 1,330 µg/m3 in the different work areas. The maximum concentrations of aluminum were 118 µg/m3 and 58 µg/m3 for PM10 and PM1, respectively, during the bagging of Al2O3 in small bags. In comparison, the maximum concentrations of titanium were 550 µg/m3 and 434 µg/m3 for PM10 and PM1, respectively, during the bagging of TiO2 and indicate a significant release of coarser particles.