The Validity and Applicability of Using a Generic Exposure Assessment Model for Occupational Exposure to Nano-Objects...

Area of Science:

• Occupational hygiene
• Nanotechnology safety
• Exposure modeling

Background:

• Control banding is a first-tier assessment for worker exposure to nano-objects, aggregates, and agglomerates (NOAA).
• Quantitative exposure estimates require advanced modeling, but nano-specific models are lacking.
• This study assesses the Advanced REACH Tool (ART), a generic model, for occupational NOAA exposure.

Purpose of the Study:

• To evaluate the validity and applicability of the Advanced REACH Tool (ART) for quantitative exposure assessment of nano-objects, aggregates, and agglomerates (NOAA).
• To determine if a generic exposure model can be adapted for predicting occupational exposure to NOAA.

Main Methods:

• The predictive capability of ART was tested using 102 NOAA exposure measurements from experimental and workplace studies.
• Relative bias and Pearson correlations were calculated between ART estimates and measured concentrations.
• Model performance was analyzed for dusts, liquid aerosols, and individual vs. combined nanomaterial scenarios.

Main Results:

• Moderate to very strong correlations were observed between ART estimates and measured NOAA concentrations.
• ART showed better correlation with dust aerosols (r=0.76) than liquid aerosols (r=0.51).
• ART consistently overestimated NOAA concentrations (factor 2-127), with higher overestimation at lower concentrations; individual nanomaterial correlations were stronger than combined scenarios.

Conclusions:

• The Advanced REACH Tool (ART) is not currently suitable for precise occupational exposure estimation of NOAA.
• However, strong correlations for individual nanomaterials suggest ART and similar generic models can be adapted for NOAA exposure assessment.
• Future models should explicitly incorporate nanomaterial-specific characteristics for improved accuracy.