04/30/14, Durham, NC., average 31 CPM

Durham, NC, United States
Altitude 500 feet
Geiger Counter Model Model 3007A w/360 Probe
Indoor
Elapsed Minutes 100
Total Counts 3,060
Overall Average CPM 31
10 Minute Average CPM 29
1 Hour Average CPM 30
Minimum CPM 19
Maximum CPM 41