Standards Development

Scope

This document provides rules for workplace sampling and the sample analysis for the detection and characterization of airborne NOAA using electron microscopy and includes:

1) the choice of appropriate samplers and their use for the detection and characterization (e.g. classification of structures and morphology) of airborne NOAA using electron microscopic methods (SEM and (S)TEM).

2) counting rules and criteria for the determination and characterisation (e.g. classification of structures, chemical composition and morphology) of airborne NOAA using electron microscopic methods (SEM and (S)TEM), especially for nanofibers and platelets.

This document is based on extensive laboratory tests for airborne NOAA.

Purpose

There is uncertainty regarding the health and safety issues associated with the handling of nanomaterials and methods to assess exposure in the workplace and characterise hazards are only partially standardised, i.e. the metrics to be used for exposure assessment, the tiered approach to collect exposure measurements, the way to operate the condensation particle counter (CPC), approach to assess dermal exposure to nanomaterials. Electron microscopy (EM) is a unique technique for physico-chemical characterisation of nano-objects and their agglomerates and aggregates (NOAA), including nanofibres (e.g. carbon nanotubes (CNTs), nanoplates (e.g. graphene) and nanoparticles). This includes Scanning Electron microscopy (SEM) and Transmission Electron microscopy (TEM), which are two different techniques with different capabilities, which will be both included in this project. For hazard and exposure (e.g. dustiness testing) assessment, EM methods are used to characterise and (potentially) quantify the airborne concentration of NOAA in addition to real-time online instruments (e.g. CPC, SMPS, ELPI), which have been listed on the OECD guideline (https://www.oecd.org/officialdocuments/publicdisplaydocumentpdf/?cote=env/jm/mono(2015)19 &doclanguage=en), but these EM methods are not harmonized, neither during sampling nor during analysis. In addition, EM methods which can quantify the airborne concentration of nanofibres and nanoplatelets and their agglomerates and aggregates are crucial, but not standardised. Without standardisation, unsuitable samplers and analyses can be used leading to false or conflicting conclusions on occupational exposure and hazard. To further develop and harmonize the use of EM techniques for quantification of airborne NOAA, an evaluation of the collection efficiency of existing EM samplers shall be carried out and sampling and analysis protocols shall be developed and validated.

That new work item proposal comprises of a merging of PWI 00137085 and PWI 00137086 which will be abandoned following acceptance of that new work item.