the $^{214}$Bi, $^{210}$Pb, $^{7}$Be, etc.), several gamma ray peaks were very easily identifiable on auto filters as seen in [**Figure \[fig:autofilter\]**]{}. A plot showing the counting rates of $^{134}$Cs, $^{137}$Cs, $^{131}$I, and $^{132}$Te from the onset of the radiation release in March 2011 through December 2012 is shown in [**Figure \[fig:auto\]**]{}, with corresponding counting rates from natural radioisotopes provided in [**Figure \[fig:autonatural\]**]{}. The counting rates for automobile filters can be converted to true airborne activities using geometrical efficiency calibrations, airflow data, and collection efficiency. However, the data presented here is intended as merely a qualitative demonstration, since mileage information for the full set of filters was unavailable. By comparison to the LBF HEPA filter data in [**Figure \[fig:allfalloutfull\]**]{}, a rough idea of the sensitivity can be established. After approximately the 100 day mark from 3/11/2011, the $^{134}$Cs and $^{137}$Cs activities in [**Figure \[fig:allfalloutfull\]**]{} from HEPA filters dropped below 10$\mu$Bq m$^{-3}$ and as seen in [**Figure \[fig:auto\]**]{}, the same isotopes still had quantifiable counting rates above background in the automobile filters. A second demonstration of detection appeared in a set of filters removed in early September of 2012 in [**Figure \[fig:auto\]**]{} where $^{131}$I reappeared, likely released as a result of a 