In 2014, the German Committee on Hazardous Substances (AGS) significantly lowered the occupational exposure limit (OEL) for the alveolar fraction of granular and biopersistent particles (GBP). Surveillance of new OELs implies new requirements for instruments and is particularly challenging for materials with low material density. Assessment of procedures involving nanomaterials is especially difficult since they mostly occur as agglomerates with sizes above the upper size limit of online measurement devices for aerosols in the ultra-fine range (< 1µm). Therefore, optical measurement devices (e.g. optical particle counter - OPC) are likely to be more adequate.
The objective of this project is a comparison of optical measurement devices operating on the basis of different physical detection principles, under controlled and reproducible conditions. The measured particle number concentrations of the different instruments are compared. In addition, mass concentrations extrapolated from the particle number concentrations are correlated to mass concentrations, measured with the MPG II (reference procedure) on the basis of gravimetry.
This work will generate insights that are important for national and international activities on standardization and harmonization. The expected outcome of the project is the identification of suitable instruments and procedures that allow for a reliable determination of workplace exposure with regard to the lowered OEL for alveolar GBP.
Unit 4.5 "Particulate Hazardous Substances, Advanced Materials"