title: Results of simultaneous radon and thoron measurements in 33 metropolitan areas of Canada.
abstract: Radon has been identified as the second leading cause of lung cancer after tobacco smoking. (222)Rn (radon gas) and (220)Rn (thoron gas) are the most common isotopes of radon. In order to assess thoron contribution to indoor radon and thoron exposure, a survey of residential radon and thoron concentrations was initiated in 2012 with ∼4000 homes in the 33 census metropolitan areas of Canada. The survey confirmed that indoor radon and thoron concentrations are not correlated and that thoron concentrations cannot be predicted from widely available radon information. The results showed that thoron contribution to the radiation dose varied from 0.5 to 6% geographically. The study indicated that, on average, thoron contributes ∼3% of the radiation dose due to indoor radon and thoron exposure in Canada. Even though the estimated average thoron concentration of 9 Bq m(-3) (population weighted) in Canada is low, the average radon concentration of 96 Bq m(-3) (population weighted) is more than double the worldwide average indoor radon concentration. It is clear that continued efforts are needed to further reduce the exposure and effectively reduce the number of lung cancers caused by radon.
authors.affiliation: Health Canada, Radiation Protection Bureau, 775 Brookfield Road, Ottawa, Canada, K1A 1C1 jing.chen@hc-sc.gc.ca.
authors.forename: Jing
authors.initials: J
authors.lastname: Chen
authors.affiliation: Health Canada, Radiation Protection Bureau, 775 Brookfield Road, Ottawa, Canada, K1A 1C1.
authors.forename: Lauren
authors.initials: L
authors.lastname: Bergman
authors.affiliation: Health Canada, Radiation Protection Bureau, 775 Brookfield Road, Ottawa, Canada, K1A 1C1.
authors.forename: Renato
authors.initials: R
authors.lastname: Falcomer
authors.affiliation: Health Canada, Radiation Protection Bureau, 775 Brookfield Road, Ottawa, Canada, K1A 1C1.
authors.forename: Jeff
authors.initials: J
authors.lastname: Whyte
mesh_terms: D016902:Air Pollution, Indoor / Q000032:analysis / Q000706:statistics & numerical data*; D000398:Air Pollution, Radioactive / Q000032:analysis / Q000706:statistics & numerical data*; D002170:Canada; D002947:Cities / Q000706:statistics & numerical data*; D006798:Housing / Q000706:statistics & numerical data*; D011834:Radiation Monitoring / Q000706:statistics & numerical data*; D011886:Radon / Q000032:analysis*
chemical_list: D011886:Radon
references.citation: J Radiol Prot. 2012 Dec;32(4):419-25
references.pmid: 23031835
references.citation: Radiat Prot Dosimetry. 2009 Jun;134(2):75-8
references.pmid: 19386773
references.citation: Radiat Prot Dosimetry. 2011 Nov;147(4):541-7
references.pmid: 21216734
references.citation: J Radiat Res. 2013 Jul 1;54(4):597-610
references.pmid: 23297318
references.citation: Radiat Environ Biophys. 2005 Dec;44(3):193-9
references.pmid: 16283349
references.citation: Am J Epidemiol. 1994 Aug 15;140(4):310-22
references.pmid: 8059766
references.citation: Radiat Prot Dosimetry. 2008;130(2):253-6
references.pmid: 18230769
references.citation: Radiat Prot Dosimetry. 2011 May;145(2-3):189-93
references.pmid: 21493608
references.citation: Radiat Prot Dosimetry. 2010 Oct;141(4):322-7
references.pmid: 20966201
references.citation: Radiat Prot Dosimetry. 2012 Nov;152(1-3):243-6
references.pmid: 22927648