Radon is a natural radioactive gas accounting for approximately one in
ten lung cancer deaths, with substantially higher death rates in
sub-Arctic communities. Radon transport is significantly reduced in
permafrost, but permafrost is now thawing due to climate change. The
effect of permafrost thawing on domestic radon exposure is unknown. Here
we present results from radon transport modeling through soil,
permafrost and model buildings either with basements or built on piles.
We find that permafrost acts as an effective radon barrier, reducing
radiation exposure to a tenth of the background level, while producing a
ten-fold increase in the radon activity behind the barrier. When we
model thawing of the permafrost barrier, we find no increase in radon to
the background level for buildings on piles. However, for buildings with
basements the radon increases to over one hundred times its initial
value and can remain above the 200 Bq/m3 threshold for up to seven years
depending on the depth of the permafrost and the speed of thawing. When
thawing speed is taken into account, radiations remains higher than the
threshold for all scenarios where 40% thawing occurs within 15 years.
This new information suggests that a significant sub-Arctic population
could be exposed to radon levels dangerous to health as a result of
climate change thawing of permafrost, with implications for health
provision, building codes and ventilation advice.