Estimating the statistics of risk from a hazardous source at long range

Plumes become very convoluted at long range due to the action of the synoptic-scale wind-field, and as a result classical descriptions, in terms of the position of the centroid and the plume width at a given range, no longer apply. This paper offers an alternative statistical description, and goes on to show methods by which the probability distributions of concentration, dosage and deposition may be derived at a receptor some hundreds or thousands of kilometres from the source using this alternative description.