Introduction Nanotechnology expresses great potential as enabling technology but there are still uncertainties about the health risks for workers potentially exposed to nano-objects and their agglomerates and aggregates (NOAA). Different methodological approaches to measure airborne NOAA in the workplace have been proposed. This study finalised a systematic review on this theme with the aim to identify techniques of exposure measurement to be recommended even in contexts with low resources, such as Low- and Middle- Income (LMI) countries.

Materials and methods We collected scientific papers reporting techniques of NOAA exposure measurements in the workplace and we summarised the data for each eligible technique according to PRISMA guidelines; then we rated the quality of evidence following an adapted GRADE approach.

Results We found 69 eligible studies to be included in qualitative synthesis: the majority of studies reported a moderate quality and only 2 studies demonstrated the use of a high quality exposure measurement technique. The review demonstrates that a basic exposure measurement, i.e. evidence for the presence or absence of NOAA in the workplace air, can be achieved with moderate (40 techniques) to high quality (2 techniques); 13 of these techniques are defined as comprehensive, since they allow also the quantification of NOAA in the workplace.

Conclusions This systematic review allowed identifying criteria for a reliable measurement of exposure to NOAA to be recommended in LMI countries. The findings of the study defined a list of requirements that must be fulfilled by an effective measurement technique (either basic or comprehensive), and highlighted the main weaknesses that need to be tackled for an effective affordability evaluation.