Sampling and counting rules for the characterization of airborne NOAA in the workplace by scanning and transmission electron microscopy

  • Project number: F 2524
  • Institution: Federal Institute for Occupational Safety and Health (BAuA)
  • Status: Ongoing Project
  • Planned end: 2024-07-01


Nanoscale fibers, e.g. Carbon nanotubes (CNT) and inorganic nanofibers are used more and more frequently today. In order to protect employees who are exposed to such fibers in the workplace, there is an urgent need for measurement methods that are valid throughout the EU to record the concentration of nanofibers.

For this purpose, two European Standards (CEN) are being created in the project:

  1. CEN for air sampling at the workplace
  2. CEN for an exposure assessment for nano objects and their agglomerates and aggregates (NOAA) (in particular high aspect ratio particles, i.e. fibers.)

The standard creation will be based on counting rules for sample evaluation using electron microscopy (EM).

The project utilizes insights from the BAuA research project nanoGRAVUR (F 2332, founded by the Ministry for Research and Education): Here, BAuA has developed a new measuring method for determining exposure to nanoscale fibres at workplaces. This method is currently being tested in project F 2445 funded by the German Social Accident Insurance (DGUV).

The workplace measurement procedure from BAuA includes personal or stationary aerosol sampling on gold-coated nuclear pore filters as well as the subsequent scanning electron microscopic analysis for the determination of the average workplace concentration of nanoscale fibres. The aim is creating an exposure assessment method based on a recommended exposure level of 0.01 fibres/ml according to the German Code of Practice TRGS 527.

After the preparation of a standard operating procedure for the new measuring and analysis method, which has been agreed upon by the project partners, it will be tested in practice by means of an interlaboratory test and subsequently by means of joint workplace measurements.

Further information


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