干旱区生态环境知识资源中心

Continuous measurements of the concentration of atmospheric Rn-222 and Rn-220 decay products in the ground-level air have been made over a period of 1 yr in the Qena desert. The variation of the isotopes level was observed continuously throughout the period. The measurements include gamma-spectroscopic analysis of samples of air collected three times per day. A distinct seasonal variation is noted for the mean values of the Rn-222 and Rn-220. The average value of Rn-222 and Rn-220 levels was (199 +/- 19 and 49.5 +/- 4.3) x 10(-5) pCi/cm3 with ratio 4.02:1.