Using air dispersion modeling as a key tool for reentry decision making following an accidental release of chemical warfare agent

Public Law 99-145 was passed in 1985 to rid the United States of aging stocks of toxic chemical munitions at eight US Army installations. The Chemical Stockpile Emergency Preparedness Program (CSEPP) was established in 1989 to develop plans for minimizing health and safety risks to the public while carrying out the stockpile destruction. A key element of CSEPP is the development of sampling strategies to aid to making reentry decisions in the unlikely event that an area becomes contaminated from a release of chemical warfare agent. Following such an event, it will be important that monitoring teams sample in a manner that maximizes success in identifying the extent and distribution of agent in a timely and cost-effective manner. These data will be used to prevent access to areas containing toxic concentrations while allowing access to areas where human health is not threatened. The successful development of a sequential sampling plan will depend, in part, on accurately predicting the agent`s deposition pattern over a given area. This paper examines methods in which the US Army`s Personal Computer Program for Chemical Hazard Protection (D2PC) can be modified to provide reasonable deposition predictions for a sequential sampling plan. D2PC, a Gaussian plume airmore » dispersion model, is designed with chemical agent characteristics, release conditions, and meteorological conditions as input. However, the model does not account for effects of terrain and vegetation on the deposition pattern. This paper focuses on the development of a geographic index that modifies the deposition pattern predicted by D2PC to account for these important factors.« less