Counts Per Minute CPM
Micro Sieverts per hour uSv/hr
Milli Sieverts Per year
Background Radiation Level Guide for
detections 1 meter above ground
12 0.10 0.88 Average background, pre Fukushima
Japan .081 uSv/hr, Australia .17 uSv/hr,
25 0.21 1.83 0.23 uSv/hr world average, USA average
0.34 uSv/hr,
50 0.42 3.65 It is normal to occasionally get short
duration peaks above normal background
for any location.
60 0.5 4.34 Larger peaks of longer duration indicate
detection of a hot spot, or a cloud of
radiation is passing through!
100 0.83 7.3 Larger peaks of longer duration indicate
detection of a hot spot, or a cloud of
radiation is passing through!
150 1.25 10.95 Detections 1.0 uSv/hr and above you are
getting into the very dangerous area of
detection, shelter or leave immediately!
500 4.17 36.5 Even more dangerous, shelter or leave
immediately!
Know what your local average background radiation level was
