The Organization for Economic Cooperation and Development (OECD) recently published the following reports:

• Evaluation of Tools and Models Used for Assessing Environmental Exposure to Manufactured Nanomaterials; Functional Assessment and Statistical Analysis of Nano-Specific Environmental Exposure Tools and Models: The objective of the project was to compile available tools and models for the assessment of environmental exposure to manufactured nanomaterials and to conduct an analysis of their applicability for use in regulatory exposure assessment. The project assesses the compiled models by providing a functional assessment, statistical analysis, and performance evaluation of each model. The functional assessment assesses the scope and use of the tools; the statistical analysis quantifies parametric sensitivity and output uncertainty in models from those tools; and the performance evaluation weighs the models against real scenarios where applicable. Finally, the recommendations provide guidance on the applicability of the tools and models in regulatory assessments.

• Evaluation of Tools and Models for Assessing Occupational and Consumer Exposure to Manufactured Nanomaterials — Part I: Compilation of tools/models and analysis for further evaluation: This joint report provides an inventory of models/tools collected under two projects, “Assessing the global readiness of regulatory and non-regulatory models for assessing occupational exposure to manufactured nanomaterials” and “Compilation of available tools and models used for assessing consumer exposure to manufactured nanomaterials and evaluation of their applicability in exposure assessments.” This joint report provides the outcomes of the scope analysis, accessibility, and support examination of models/tools, and the outcomes of sensitivity analysis of models/tools.

• Evaluation of Tools and Models for Assessing Occupational and Consumer Exposure to Manufactured Nanomaterials — Part II: Performance testing results of tools/models for occupational exposure: The report assesses the performance testing of 15 tools (ten nanospecific and five conventional chemical tools recommended by the European Chemicals Agency (ECHA)) for their use for exposure assessment of nanomaterials in occupational environments. The performance testing consisted of comparing the tools’ output with experimentally measured exposure levels. The general strategy for the assessment of the performance testing was to look at the Spearman correlation between output and measured exposure, as well as to quantify the percentage of underestimation. The tools were considered adequate for the assessment of nanomaterials in occupational environments when Spearman correlation was higher than 0.6 and the real measurement concentrations do not exceed the model estimates for more than ten percent of the total comparisons.

• Evaluation of Tools and Models for Assessing Occupational and Consumer Exposure to Manufactured Nanomaterials — Part III: Performance testing results of tools/models for consumer exposure: The performance testing assesses the predictive capability of models/tools by comparing the output of models/tools with measurement data. It determines whether the models/tools tend to overestimate or underestimate the exposure. It also determines the rank correlation between model/tool estimates and measurement data. In addition, the performance testing provides recommendations for consideration where appropriate when conducting studies to collect data relevant to consumer exposure assessment of manufactured nanomaterials.

On December 2, 2021, OECD will host a webinar on how to assess exposure to nanomaterials. According to OECD, scientific knowledge to assess exposure to nanomaterials continues to improve, and new exposure tools and models for nanomaterials are being developed. To promote development in this area further, OECD compiled an inventory of available models and tools for assessing occupational, consumer, and environmental exposure to nanomaterials. OECD initially compiled 54 tools and models, and after in-depth analyses, ten occupational, seven consumer, and six environmental tools/models were recommended or evaluated as suitable for assessing exposure to nanomaterials. Detailed information on the analyses and evaluations are provided in the reports listed above. During the webinar, the researchers will present the key findings of the reports. Speakers and presentations will include:

• Occupational project: Carla Ribalta Carrasco, Ph.D. (Danish National Research Center for Working Environment);

• Consumer project: Mohammad Zein Aghaji, Ph.D. (Health Canada); and

• Environmental project: Marc LaPointe, Mathieu Dextraze (Environment and Climate Change Canada).