Avoiding typical conflicts in risk communication

Communication of the results of exposure assessment uncertainties to the different stakeholders should reflect the different needs of the audiences in a transparent and understandable manner. 

Part 1 of this IPCS Harmonization Project Document describes, characterizes and provides guidance for uncertainty analysis in routine exposure assessment work. It also discusses challenges and limitations, as it cannot answer all the questions that may be posed in uncertainty analysis rather, it demonstrates that uncertainty analysis is a dynamic process. 

An uncertainty analysis gives the assessor the opportunity to re-evaluate the scenario, model approaches and parameters of the analysis and to consider their influence in the overall analysis. The practical impact of uncertainty analysis is illustrated within the annexed case-studies, which also clarify how uncertainty analyses follow a systematic methodology, based on a tiered approach, and consider all possible sources of uncertainty. The first step in uncertainty analysis consists of a screening, followed by a qualitative analysis and two levels of quantitative analysis, using deterministic and probabilistic data. The assessor should be aware that an uncertainty analysis cannot answer all the questions, which, moreover, may lead to new questions. 

Finally, the results of the uncertainty analysis should be adequately communicated, together with the results of the assessment. Addressing the uncertainties of the exposure assessment enables the risk assessor to distinguish risk characterization and risk assessment. Further, the results of the exposure assessment enable the risk manager to identify the key factors that influence exposures and risks. 

Key guiding principles for uncertainty analysis are identified throughout the text and provided together in the Executive Summary. These guiding principles are considered to be the general desirable goals or properties of a good exposure assessment. 

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