Exposure to manufactured nanostructured particles in an industrial pilot plant.

OBJECTIVES: Nanomaterial production and the number of people directly in contact with these materials are increasing. Yet, little is known on the association between exposure and corresponding risks, such as pulmonary inflammation and oxidative stress.
METHODS: Condensation Particle Counters, a DustTrak and Scanning Mobility Particle Sizer quantified real-time size, mass and number concentrations in a nanostructure particle pilot-scale production facility, using a high-temperature gas-phase process, over a 25-day period. Temporal and spatial analysis of particle concentrations and sizes was performed during production, maintenance and handling. Number-based particle retention of breathing mask filters used under real-time production and exposure conditions in the workplace was quantified.
RESULTS: The results demonstrate elevated number concentrations during production, which can be an order of magnitude higher than background levels. Average concentrations during production were 59,100 cm(-3) and 0.188 mg m(-3) for submicron particles. Mask filters decreased particle number concentrations by >96%.
CONCLUSIONS: This study demonstrates real-time worker exposure during gas-phase nanoparticle manufacturing. Qualitative and quantitative analysis of emission sources and concentration levels in a production plant is accomplished. These results are important for workers, employers and regulators in the nanotechnology field as they provide information on encountered exposures and possibilities for mitigation measures.