Methodology for qualitative uncertainty characterization

The methodology for qualitatively characterizing the uncertainty of the exposure assessment consists of two basic steps  

These steps are analysed in the sections that follow. 

The three main classes of sources of uncertainty (section 3.2) are scenario uncertainty , model uncertainty (in both conceptual model formulation and mathematical model formulation) and parameter uncertainty (both epistemic and aleatory). The uncertainty of the conceptual model source concentrates on the relationship between the selected model and the scenario under consideration. 

The nature and extent of the qualitative characterization of these sources of uncertainty are necessarily dependent on the objective of the exposure assessment and the appropriate form of output for its intended purpose. Prior to initiating the development of any assessment, its intended purpose must be clearly articulated. 

Each of the three basic sources of uncertainty— scenario , model and parameter —can be further detailed in order to characterize each basic component separately (Table 1). 

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