for further investigation. After determining the true presence of an isotope of concern, routes from logbooks can be determined and teams could be scrambled somewhat quickly to perform more thorough sweeps of areas looking for potential sources of radioactivity simply by driving vehicles and quickly analyzing filters upon return, or perhaps with more sophisticated portable filtration and detection systems. Second, in the event of a large-scale disaster, networks of automobiles could be deployed to determine the level and extent of contamination across large regions and could be analyzed via a large network of existing detectors at laboratories and universities nationally.

The Low Background Facility at LBNL obtains automobile filters from the Berkeley Police Department every few weeks. At regular maintenance intervals, air filters are removed and (ideally) the odometer readings are recorded. In the LBF pilot program, the filters are initially screened at the vehicle maintenance shop using a First Response Detector (FRD) composed of a 2x2 NaI detector within a 2 inch thick steel shield. Here, only gross counts of filters are noted. If any filters were to exhibit gross counting rates above background, such filters would take priority in screening. In this study no filters have ever registered 