title: The Validity and Applicability of Using a Generic Exposure Assessment Model for Occupational Exposure to Nano-Objects and Their Aggregates and Agglomerates.
abstract: BACKGROUND
  Control banding can be used as a first-tier assessment to control worker exposure to nano-objects and their aggregates and agglomerates (NOAA). In a second tier, more advanced modelling approaches are needed to produce quantitative exposure estimates. As currently no general quantitative nano-specific exposure models are available, this study evaluated the validity and applicability of using a generic exposure assessment model (the Advanced REACH Tool-ART) for occupational exposure to NOAA.
  
  
  METHODS
  The predictive capability of ART for occupational exposure to NOAA was tested by calculating the relative bias and correlations (Pearson) between the model estimates and measured concentrations using a dataset of 102 NOAA exposure measurements collected during experimental and workplace exposure studies.
  
  
  RESULTS
  Moderate to (very) strong correlations between the ART estimates and measured concentrations were found. Estimates correlated better to measured concentration levels of dust (r = 0.76, P < 0.01) than liquid aerosols (r = 0.51, P = 0.19). However, ART overestimated the measured NOAA concentrations for both the experimental and field measurements (factor 2-127). Overestimation was highest at low concentrations and decreased with increasing concentration. Correlations seemed to be better when looking at the nanomaterials individually compared to combined scenarios, indicating that nanomaterial-specific characteristics are not well captured within the mechanistic model of the ART.
  
  
  CONCLUSIONS
  Although ART in its current state is not capable to estimate occupational exposure to NOAA, the strong correlations for the individual nanomaterials indicate that the ART (and potentially other generic exposure models) have the potential to be extended or adapted for exposure to NOAA. In the future, studies investigating the potential to estimate exposure to NOAA should incorporate more explicitly nanomaterial-specific characteristics in their models.
authors.affiliation: 1.Division of Environmental Epidemiology, Institute for Risk Assessment Sciences, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands; cindy.bekker@rivm.nl.|2.TNO, Department Risk Analysis of Products in Development, Utrechtseweg 48, 3704 HE Zeist, The Netherlands.
authors.forename: Cindy
authors.initials: C
authors.lastname: Bekker
authors.affiliation: 2.TNO, Department Risk Analysis of Products in Development, Utrechtseweg 48, 3704 HE Zeist, The Netherlands.
authors.forename: Eef
authors.initials: E
authors.lastname: Voogd
authors.affiliation: 2.TNO, Department Risk Analysis of Products in Development, Utrechtseweg 48, 3704 HE Zeist, The Netherlands.
authors.forename: Wouter
authors.initials: W
authors.lastname: Fransman
authors.affiliation: 1.Division of Environmental Epidemiology, Institute for Risk Assessment Sciences, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands.
authors.forename: Roel
authors.initials: R
authors.lastname: Vermeulen
mesh_terms: D000336:Aerosols / Q000032:analysis; D000395:Air Pollutants, Occupational / Q000032:analysis; D004391:Dust / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods; D006801:Humans; D019570:Inhalation Exposure / Q000032:analysis*; D008962:Models, Theoretical; D049329:Nanostructures; D016273:Occupational Exposure; D018570:Risk Assessment; D017132:Workplace / Q000706:statistics & numerical data
chemical_list: D000336:Aerosols; D000395:Air Pollutants, Occupational; D004391:Dust
keywords: NOAA; exposure modelling; validation