Meteorological influences upon the radon‐content of soil‐gas

Abstract

This paper is a continuation of one given at the Twenty‐Fifth Annual Meeting of the American Geophysical Union, in June, 1944, on “A study of the radoncontent of soil‐gas” [see 1 of “References” at end of paper]. The present paper covers the period from May 17, 1944, to March 25, 1945. Its main purpose is to consider the meteorological influences upon the radon‐content, such as barometricpressure changes, wind‐velocity effects, and temperature‐variations.Four depths, 25, 75, 150, and 200 cm, were investigated. In the course of 177 days of actual investigation during this period, covering 642 Individual readings, the radon‐content of the soil‐gas was measured.Ionization‐chambers connected with a Wulf bifilar‐electrometer were used, and the amount of radon was calculated in (curie/cc) X 10−14 , after calibrating the apparatus by means of a standard solution of radium.From the results obtained the following conclusions can be drawn:(1) Dry ground produces constant values of the radon‐content at each depth and shows an increase of the content with depth.(2) A long period of snow‐and‐ice‐coverage of the ground causes all pipes to approach the same value. Frozen ground gives the highest values for the year.(3) Barometric pressure causes, at least to a depth of 200 cm, a variation such that an increasing pressure tends to decrease the radon‐content, while a decreasing pressure produces an increase in radon‐content. This effect is most pronounced at the 25‐ and 75‐cm levels.(4) A high wind‐velocity over a number of hours will noticeably reduce the radon‐content in the top layers of the ground.(5) Ground‐temperature changes have apparently no great effect upon the radoncontent of soil‐gas.