Risk Assessment

Classically, occupational exposure to airborne particles has been characterised in terms of the mass of material present per unit volume (mg/m3). Measurements are based on the workers breathing zone and are taken using personal samplers developed using guidance on inhalable, thoracic, respirable fractions provided in ISO 7708 (1995). Measurement of high aspect ratio particles such as fibres is however based on a different approach and requires counting of these particles to achieve a number concentration.

Although there is not yet sufficient evidence to clearly identify which metric should be measured to assess exposure to nanostructured particles (NP), current published information support the concept that surface-area metric could be relevant when surface (area, shape, chemistry, reactivity…) is involved in biological interactions. In recent years, there are direct-reading instruments that have been designed to provide NP surface-area concentration measurement by means of the rate at which positive ions diffuse to NP.

Handling of powders generates dust causing potential exposure of workers. Handling scenarios can vary greatly making it difficult to determine and compare dustiness properties of different materials of different primary particle sizes. Bench-scale dustiness tests subject the test material to a standard challenge and very reproducible results can be obtained. We have used a specially developed rotating drum dustiness tester that requires only 6 g of test material per run.

In the literature, European and North-American studies have reported increased risks of nasal, throat and skin symptoms correlated to exposure to printers. In addition, recently significant relationships with the general symptoms such as headache and fatigue, chronic bronchitis, breathlessness, and tonsillitis and middle ear infections were found. In fact laser printers and copiers are suspected to emit toner dusts and Volatile Organic Compounds (VOCs) and, thereby, to represent a health risk.

The recent development of nanotechnologies allows a careful and aimed risk assessment within workers are involved. To achieve such goal a specific risk assessment model has been drawn up with reference to the workplaces where nanoparticles are present. This model allows to identify and quantify the health hazards for workers. The risk assessment is implemented for each workplace and for the work activity typology; it is based on the following factors: numerousness of the exposed workers, frequency of exposure, dimensions of the nanoparticles, nanoparticles behaviour (ex.

Nanotechnology enables the production of structures and materials with new properties and with predicted huge benefits for society. Simultaneously, there are concerns that nanomaterials may introduce new risks to humans and the environment. Therefore, in the Communication Towards a European Strategy for Nanotechnology from 2004, the European Commission states that R&D and technological progress need to be accompanied by scientific investigation and assessment of possible health or environmental risks associated with nanotechnology.