Autonomous Detection Systems (ADS), also called biohazard detection systems or autonomous pathogen detection systems, are designed to monitor air in an environment and to detect the presence of airborne chemicals, toxins, pathogens, or other biological agents capable of causing human illness or death. These systems monitor the air continuously and send real-time alerts to appropriate authorities in the event of an act of bioterrorism or biological warfare. History In the United States, an ADS system (BDS) was developed for the U.S. Postal Service following the 2001 anthrax attacks. The first detection systems in U.S postal services were installed in 2006. To counter such problems in the future, the United States federal government set up a program called BioWatch, which operates in more than 21 cities in the US. BioWatch The BioWatch program is funded and supervised by the Department of Homeland Security (DHS). The BioWatch program has three main components: sampling, analysis, and response. Each of these components is handled by three different agencies. The Environmental Protection Agency (EPA) handles the sampling component: the sensors that collect airborne particles. The Centers for Disease Control and Prevention (CDC) coordinates the analysis and laboratory testing of the samples. Local authorities are responsible for the public health response to positive findings. The Federal Bureau of Investigation (FBI) is designated as the lead agency for the law enforcement response if a bioterrorism event is detected. (Shea and Lister, 2003) Mechanism APDS monitors the air for the three types of biological threat agents: bacteria, viruses, and toxins. The autonomous detection system is capable of (1) rapidly processing and accurately analyzing aerosol samples with a high level of confidence; (2) automating and integrating the major system functions into the detector, including aerosol sample collection, preparation, analysis, and analytical results reporting; (3) operating in its intended indoor and outdoor environments; and (4) disseminating and archiving analysis results and system operational data via the C3 network, known as the BioWatch Gen-3 Operations Support Service. APDS operates continuously; the system can detect low concentrations of bioagents that might go undetected by a system that is triggered only when the overall number of particles in the air is high. APDS collects samples, prepares them for analysis, and tests for multiple biological agents. This automation reduces the cost and staffing that would be required to manually analyze samples. As APDS collects air samples, it first runs them through an immunoassay detector.