There are also communities of hobbyists that track radioactivity with custom or home-brew stations. While less sophisticated in what they measure they can be an

There are also communities of hobbyists that track radioactivity with custom or home-brew stations. While less sophisticated in what they measure they can be an another point of reference. One of the oldest around is http://radioactiveathome.org/map/ http://radioactiveathome.org/map/ another is http://www.uradmonitor.com/ http://www.uradmonitor.com/