Introduction
under-appreciated determinant of radon-induced lung cancer risk , and support a need for targeted radon testing and reduction in rural communities .
Article Open access09 December 2022
Introduction
Radioactive radon ( 222 Rn ) exposure is an indoor air environmental carcinogen that is among the most prevalent non-tobacco causes of lung cancer , alongside 2.5-micron particulate matter ( PM 2 . 5 ) air pollutants , arsenic metalloids , and severe lung inflammation from infectious disease and / or silicate exposure1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 . The inhalation of gaseous radon and its solid radioactive progeny increases the relative lifetime risk of lung cancer by emitting alpha particle radiation that damages lung epithelial cell DNA , raising the likelihood of cancer-causing genetic mutations12 , 13 , 14 , 15 , 16 . Radioactivity from decaying radon ( and radon progeny ) in indoor air is measured in Becquerels ( Bq ), equating with one alpha particle emission per second , per cubic metre ( m 3 ) of air , with a total of four alpha particle emissions occurring as 222 Rn decays into stable 210 Pb over time16 . For large populations , there is a 16 % increase in relative lifetime risk of lung cancer per 100 Bq / m 3 of radon exposure that , based on the documented activity pattern of a typical North American adult , equates to an absorbed dose of ~ 4 millisieverts ( mSv ) per year ( mSv / y ) of particle radiation17 , 18 , 19 , 20 , 21 . Understanding excess radon exposure is important because a substantial number of people diagnosed with lung cancer that do not meet current inclusion criteria for early cancer detection programs ( e . g ., 40 % of Canadian patients ), as they have used tobacco to only a limited extent (~ 20 % of patients ), or have never used tobacco at all ( another ~ 20 % of patients ) 22 , 23 , 24 , 25 , 26 , 27 , 28 .
At a population and individual level , radon exposure arises from a complex convergence of geologic , built environment , demographic , lifestyle , and behavioural factors19 , 20 , 21 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 . In Canada , evolving building practices over the 20th to 21st century have increasingly and unintentionally captured , contained , and concentrated alpha radiation emitting radionuclides from radon within the residential built environment to unnaturally high and unsafe levels29 , 31 , 37 . Radiation doses from radon inhalation are also a function