Average Airborne Gross Beta Concentrations (n) | |||
Year | 5 States (18 Sites) | 5 States (10 Sites) | Other U.S. |
March 15-April 30 | |||
2010 | 0.005112 (190) | 0.005130 (132) | 0.008527 (401) |
2011 | 0.033016 (225) | 0.029563 (138) | 0.020204 (378) |
2011/2010 Ratio** | 7.345 | 5.253 | 2.397 |
Other Dates January 1-October 4 | |||
2010 | 0.006027 (853) | 0.006184 (660) | 0.009573 (1810) |
2011 | 0.005526 (858) | 0.005550 (564) | 0.009670 (1679) |
2011/2010 Ratio** | 0.983 | 0.0889 | 1.018 |
3/15-4/30 ratio/ | 7.472 | 5.909 | 2.355 |
Other Dates ratio |