Guidelines for ranking uncertainties in atmospheric dispersion

A literature review has been conducted to investigate the extent to which the uncertainty on atmospheric dispersion models’ various input variables has an effect on the models’ outputs, and in particular to determine which input variables are most influential in the sense of giving rise to the largest uncertainties on those outputs.

The wide range of models, parameters and scenarios uncovered in the review meant that it was difficult to make a meaningful comparison among them; however, certain patterns were apparent. Consequently, rather than determining a quantitative ranking, parameters have been grouped into approximate categories according to the influence their uncertainties might have on modelling results.