initial arrival, comparable to natural radioisotopes that are always present, but fell much below natural background activities quickly. In addition, it is also worth noting that only $^{210}$Pb and $^{7}$Be were plotted, and there are many other $^{222}$Rn daughters such as $^{214}$Bi not shown in [**Figure \[fig:pbbe\]**]{} since most $^{222}$Rn daughters are quite short lived. The measurements of airborne fallout activities presented here are also in reasonable agreement with the results of another local group at UC Berkeley who made measurements in the area [@Bandstra2011].

![A HPGe gamma ray spectrum from an air filter exposed March 23-24, 2011 at the LBF facility at LBNL containing both natural and fission nuclides. This spectrum represents a full 24 hour exposure period and was counted for a livetime of 1250 minutes immediately upon being removed from the air sampler. More information on the peaks displayed here are listed in [**Table \[tab:isotopes\]**]{}.[]{data-label="fig:airfilter"}](26099-AirFilter){width="\linewidth"}

![Long term airborne concentrations fission products from March 11, 2011 to the end of 2012 as measured on HEPA filters at the LBF in Berkeley, CA. Horizontal error bars, when visible, represent filter exposure periods. Missing error bars are smaller than the visible data marker. Plotted uncertainties seen here are statistical only, 