Objective The use of nanotechnology is growing enormously and occupational physicians have an increasing interest in evaluating potential hazards and finding biomarkers of effect in workers exposed to nanoparticles.

Methods A study was carried out with 36 workers exposed to (nano)TiO₂ pigment and 45 controls. Condensate (EBC) titanium and markers of oxidation of nucleic acids (including 8-hydroxy-2-deoxyguanosine (8-OHdG), 8-hydroxyguanosine (8-OHG), 5-hydroxymethyl uracil (5-OHMeU)) and proteins (such as o-tyrosine (o-Tyr), 3-chlorotyrosine (3-ClTyr) and 3-nitrotyrosine (3-NOTyr)) were analysed from samples of their exhaled breath.

Results In the production workshops, the median total mass 2012 and 2013 TiO₂ concentrations were 0.65 and 0.40 mg/m³, respectively. The median numbers of concentrations measured by the scanning mobility particle sizer (SMPS) and aerodynamic particle sizer (APS) were 1.98×10⁴ and 2.32×10⁴ particles/cm³, respectively; and about 80% of those particles were smaller than 100 nm in diameter. In the research workspace, lower aerosol concentrations (0.16 mg/m³ and 1.32×10⁴ particles/cm³) were found. Titanium in the EBC was significantly higher in production workers (p<0.001) than in research workers and unexposed controls. Accordingly, most EBC oxidative stress markers, including in the preshift samples, were higher in production workers than in the two other groups. Multiple regression analysis confirmed an association between the production of TiO₂ and the levels of studied biomarkers.

Conclusions The concentration of titanium in EBC may serve as a direct exposure marker in workers producing TiO₂ pigment; the markers of oxidative stress reflect the local biological effect of (nano)TiO₂ in the respiratory tract of the exposed workers.