Radon in the environment - opportunities and hazards

One of the many subjects that particle track etching has been applied to is radon, and radon in turn is of interest in many contexts. It is a ubiquitous hazard to human health, concentrated in certain geological settings and further intensified by certain home-construction practices. Radon also acts usefully as a tracer for minerals, underground fluid flow, and stresses within the earth. Track methods of radon and radon-daughter measurements are surveyed. Applications are given to measurements of both indoor and outdoor radon for health physics, and an approach is noted to the knotty problems of retrospective studies of individual exposures. Numerous results show evidence of fluid flow through pore spaces in the ground. This flow transports radon and leads to other applications, such as locating subsurface uranium ore, and oil and natural gas deposits. Examples of premonitory radon signals from seismic events are also given. (author)