Sensitivity of Air Model Results to Input Parameter Selection

摘要

The recently released US EPA Office of Solid Waste protocol for performing human health risk assessments (HHRAP) recommends the EPA-developed ISCST3 air dispersion model for determining ambient air concentration and wet and dry deposition rates of emitted contaminants of potential concern (COPC). Several input parameter values are specified by the modeler from the literature and model user guides. HHRAP recommends values characteristic of typical sites without requiring site-specific data collection. However, modelers may collect site-specific data to refine results. This sensitivity analysis compares modeled results using HHRAP recommended values to results using upper and lower range values from the literature. Fifteen elements are evaluated based on availability of information, experience on risk analyses, and theoretical impact on modeled results. A qualitative summary of the study results is provided. 'Slight' variations are less than 10% between the element range limits and the HHRAP recommended values. 'Moderate' variations are less than 50% between results. 'Severe' variations are greater than 50%. Seven elements produce slight or no variations. Two elements produce moderate variations. Six elements produce severe variations. For severe variations, the modeler should use the methods in the HHRAP with site-specific data to select representative input parameters.