Fixed station ambient monitoring

Although a number of papers have commented on the possible deficiencies of ambient fixed-station monitory networks, (17-19) more recent papers have recognized the primary difficulty as a failure to identify what questions are being asked that the monitoring and assessment program is supposed to answer (20-24). 

Most of the atmospheric oxidant and ozone data—as well as the experimentally determined exposure data for v tation, animals, and humans—have been obtained with analyzers that sample and record the ambient concentrations almost continuously during the period of observation. The response times are usually acceptable for fixed-station monitoring, because data describing hourly averages are sufficient. Faster responses are needed, however, for studying chemical reaction rates, retention on inhalation, sampling while in motion (as from aircraft), and expediting calibrations. The response times required are therefore a function of the resolution needed. 

The PROTECT architecture consists of sensors deployed in various subway stations, complemented by closed-circuit television (CCTV) cameras that have automated and manual pan-tilt-zoom capabilities. These sensor and camera combinations provide data continuously to a centralized chemical-biological emergency management information system (CB-EMIS developed by Argonne National Laboratory) located in a centralized WMATA operations control center. In addition to the sensor and video data from the stations, train operation data and ambient meteorological data are also ported to the CB-EMIS system. Under normal operations, CB-EMIS can provide operator access to the multiple fixed and movable cameras throughout the metro system to assist law enforcement officers or firefighters. It also monitors the status of the sensor systems deployed in the metro. 

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