Elevated indoor exposure in Chinese carbon brick and cave dwellings

In two rural provinces of China residents are exposed to significantly elevated levels of natural radiation: in Gansu Province millions of people have been living in earth-dug cave dwellings for several generations; in Jiangxi Province several hundred thousand inhabitants reside in carbon-brick dwellings, containing elevated levels of 238U and 226Ra. In a pilot study regional lung cancer mortality rates were investigated in the affected areas and were found to be higher than for control groups in normal dwellings in the same area.