Operational systems predict the consequences of atmospheric releases of hazardous materials for real-time emergency response, pre-event planning, and post-incident assessment. Such systems provide federal, state, and local agencies, emergency planners and responders, public health officials, military personnel, and other users with critical information on which to base life-and-death decisions on safe zones for siting of incident command posts, sheltering-in-place or evacuation advisories, the need for protective equipment, and the utilization of hospital and health care resources. A range of operational modeling capabilities is required to support different types of release events, distance scales, and response times. Fast-response deployable models are used to perform hazard assessments and initial response functions, and can serve as a backup when connections to a reach-back center are not available. Higher-fidelity three-dimensional dispersion models, coupled to real-time observational data and numerical weather prediction model output, are used for real-time response and support expert quality-assured predictions and refined assessments. Computational fluid dynamics models, which explicitly resolve urban structures, are used for high fidelity applications including vulnerability analyses and planning studies. This paper will briefly discuss the types and capabilities of models used or under development for emergency response systems, customer products, supporting data, and a few representative examples of operational systems. Some selected research priorities are summarized in the final sections.
