Key sources of imprecision in radiological emergency response assessments.

In the first few hours after an accidental release of radioactivity to the atmosphere it is likely that limited measurements of radioactivity in the environment will be available on which to make decisions concerning protection measures and radiation monitoring activities, and that monitoring data will be supplemented by the predictions of models. There will be imprecision associated with these predictions, partly resulting from lack of knowledge (for example, about the nature of the release and the actual state of the weather), partly due to imprecision in the models themselves and partly due to intrinsic imprecision associated with the accuracy of the measurements. This study considers the relative importance of the key parameters influencing assessment imprecision and discusses the implications for emergency response systems.