Objectives

The project aims to improve metrological traceability and reduce uncertainty in number-concentration measurements of relevant engineered particles and pollutants, by delivering validated, traceable, standardised approaches for the determination of particle density and refractive index.

1. Develop at least three representative test materials (RTMs) which include industrially relevant or polluted particles, covering sizes (1 nm -1000 nm) and concentrations (10³–10¹⁴ g⁻¹), complete with characterised density and refractive index.

2. Assess and verify particle counting and ensemble methods (e.g. spICP-MS, PTA, SAXS, MADLS, CLS, UV-Vis, Raman spectroscopy) on RTMs. Develop new sample preparation protocols and run an interlaboratory comparison (ILC).

3. Develop traceable methods to reduce concentration measurement uncertainty to 20%. Define density and refractive index uncertainty requirements. Use a range of measurement techniques including TGA, CLS, XRD, FCM, UV-VIS, FFF-RI, and light scattering. 

4. Validate in silico modelling for material parameters in measurement and develop a roadmap for traceability and standardisation of refractive index for particles.

5. Engage with standards bodies and users (CEN, ISO), contribute to revising and drafting standards, and initiate three new documentary standards on particle density and refractive index, and absolute number concentration by microscopy.