From nano to micrometer size particles – a characterization of airborne cement particles during construction activities

Abstract Although, photocatalytic cement contains nanosized TiO2, a possibly carcinogen, no exposure assessments exist for construction workers. We characterized airborne nanoparticle exposures during construction activities simulated in an exposure chamber. We collected some construction site samples for regular cement in Switzerland and Thailand for comparison. Airborne nanoparticles were characterized using scanning mobility particle sizer (SMPS), portable aerosol spectrometer (PAS), diffusion size classifier (DiSCmini), transmission electron microscopy (TEM), scanning electron microscope energy dispersive X-ray spectroscopy (SEM-EDX), and X-ray diffraction. Bagged photocatalytic cement had 2.0 wt% (GSD ± 0.55) TiO2, while TiO2 in aerosols reached 16.5 wt% (GSD ± 1.72) during bag emptying and 9.7 wt% (GSD ± 1.36) after sweeping. The airborne photocatalytic cement particles were far smaller (approximately 50 nm) compared to regular cement. Cutting blocks made from photocatalytic cement or concrete, resulted in similar amounts of airborne nano TiO2 (2.0 wt% GSD ± 0.57) particles as in bagged material. Both photocatalytic and regular cement had a geometric mean diameter (GMD)