Abstract
The content of radioactive substances in the atmosphere near the ground was measured in Tokyo, and the mean value is 0.9×10-16 curie/cm3 in the daytime and 2.3×10-16curie/cm3 at night. Using these observed values and the coefficient of eddy diffusivity estimated from the method of atmospheric electricity described in the previous paper(1), we calculated the hourly values of the content of radioactive substances. The rate of ion pair production by the α ray emitted by the radioactive substances in the atmosphere is estimated. The earth radiation was measured, and ion pair production by that is (3.0±0.1) J. Using these data, the rate of total ion pair production in the atmosphere are estimated.
