Ultrafine aerosols and nanoparticles at the workplace

Together with biotechnology and information technology, nanotechnology is regarded as one of the driving forces behind a new industrial revolution which will impact upon the lives of all people in various ways. According to estimates, nanoscale products or products manufactured with the aid of nanotechnology will account for trade to a value of US$1 trillion by 2015. Compared to larger particles of the same material nanomaterials and nanoparticles by virtue of their new properties enable new products with either significantly better performance or completely new characteristics.

What are nanoparticles?

"Nanoparticles" is the colloquial term for objects with two or three dimensions of between 1 and 100nm and manufactured specifically for their particular material properties.

What are ultrafine dusts?

Ultrafine dusts likewise exhibit particle sizes in the range from 1 to 100 nm. They are however produced unintentionally, for example during thermal processes (engine exhaust fumes, welding processes, domestic heating, candlelight) or the machining of materials. Particles with dimensions of 1 to 100 nm can also be found in aerosols in the natural environment. The precise definition of nanoparticles and ultrafine particles is contained in the ISO/TS 27687 prestandard, "Terminology and definition for nano-objects".

Agglomerates and aggregates

Both nanoparticles and ultrafine particles may occur as either agglomerates or aggregates. In these cases, many much smaller particles are combined to varying degrees to form larger structures. The question of whether nanoparticles may be released from agglomerates or aggregates in the human body, and if so under what conditions, is the subject of intensive research.

The surface is responsible for the effect

The new, desired properties of nanoscale materials prompt the question of whether the existing methods for the toxicological testing of substances are also appropriate for nanoscale particles. Nanoparticles can be expected to penetrate barriers in the body and to enter organs inaccessible to larger particles.

Both the desired and undesired effects of nanoparticles are partly attributable, independent of their chemical nature, to their surface area and particle number, which are greater by orders of magnitude than those of coarser particles of the same composition. If we imagine dividing a cube with an edge length of 1 cm and a surface of 6 cm² into cubes with an edge length of 1 nm, the result is 10²¹ cubes with a total surface area of 6 000 m². The total mass and volume of the cubes remains unchanged, however.