FIGURE 2.2 Generic multistage architecture.

release region, alerting nearby staff to note any irregularities, and reducing the personnel traffic into areas that might be affected should the release be confirmed.

If bioaerosol levels far higher than background are observed, or if a rapid identifier operated in parallel yields a positive report, more significant actions can be initiated. These might include evacuations, temporary personal protection measures, movement restrictions, and other actions that will disrupt or halt normal facility operations. Final confirmation of the attack by the most specific detection system will open the door to a full complement of responses, including medical measures and evaluation of the overall scope of the attack beyond the bounds of the facility. Even for very specific detectors, validation of the presence of an attack by a second detection technology may be valuable when the lowest possible false alarm rate is required.

The end-to-end performance of a detect-to-warn architecture will depend on numerous factors, including scenario uncertainties, detection system capabilities, and response effectiveness. Examples of several nominal defenses are postulated and analyzed in Chapter 10. These examples point to the promise of significant defensive capability against some attacks. Many challenging analysis, design, and demonstration tasks remain before this promise is realized, not only for the detection technologies but also for the overall defensive system.