Tidal synchronicity of built‐environment radon levels in the UK

In our recent work on radon in UK homes the authors have observed tidal‐periodic variations in built‐environment radon levels and here report results from our ongoing investigations. These tidal variations have been quantified using a variety of analytical techniques, including a novel correlation technique developed as part of this investigation. The observed variations are cyclic at the 14–15‐day tidal period and lag new/full moons by varying periods of days, the magnitude of the variation and lag being dependent on factors such as location, underlying geology and rock/soil hydration. As well as quantification and discussion of tidal effects on radon levels, the potential effects of such phenomena on the reliability of short‐term radon measurements are discussed.