Iodine-131 data from CTBTO monitoring stations

I found these two interesting graphics on the website of Germany’s Federal Office for Radiation Protection.

The first graph shows the concentration of airborne Iodine-131 at monitoring stations around the northern hemisphere. It is very interesting to see how quickly the Iodine-131 concentration reached relative equilibrium across the northern hemisphere (with the exception of Japan):
 
The second image shows the spatial-temporal detection of Fukushima origin radionuclides at each testing station. Unfortunately no associated data for each station is being published yet.

In addition, the U.S. EPA has published detailed data for a number of radionuclides (*PDF*) from its RadNet monitoring network for western U.S. monitoring stations. Interestingly, the data for Dutch Harbor, Alaska show cartridge based monitors have detected I-131 an order of magnitude greater (2.8 pCi/m3) than that detected by filter based monitoring equipment (0.20 pCi/m3) at the same location and date (both values are very small). No explanation for the discrepancy is provided, but similar trends are apparent from other stations using both types of equipment.