For example, the weather at Ukhaydir was affected not only by the local terrain but possibly also by breezes from several lakes to the north. After running these models, the modeling team had sufficiently detailed information about specific weather conditions for use in the transport and diffusion models. The source characterization was the same as that developed by the CIA for its preliminary modeling, i.e., an instantaneous release of seven gallons followed by a sustained release of 83 gallons over three days. Although the evaporation of agent from the crater would have taken place over a number of days, the decreasing release rate, as well as the generally calm weather conditions, would have limited any potential hazard areas after the first 72 hours. Dosage information determines which parts of the hazard areas represent the greatest potential danger for exposed personnel.
Dosage is defined as concentration integrated over a specific time period of exposure.
DoD used the general population limit to model the area of potential exposure. The general population limit is the average concentration below which the general population, including children and the elderly, could remain indefinitely with no effects. Because there was no specific information about how these mechanisms might affect the amount of agent degraded during transport and dispersion, the modelers used a more conservative approach and did not use them to limit the extent of the hazard areas. The modelers then overlaid the hazard areas produced by these three simulations and used the outermost perimeter of the union to define an ensemble hazard area. Any assessment of the likelihood of exposure of US troops to mustard agent released from Ukhaydir depends on how close the modeled hazard areas came to known troop locations.