Mixtures of radon and thoron daughters in underground atmospheres.
D000398:Air Pollution, Radioactive / Q000032:analysis*; D000512:Alpha Particles; D002170:Canada; D006801:Humans; D008906:Mining; D011886:Radon / Q000032:analysis*; D013057:Spectrum Analysis; D013910:Thorium / Q000032:analysis*; D014501:Uranium
D014501:Uranium; D013910:Thorium; D011886:Radon