Radon is a potent and preventable lung cancer risk
Radon is the second-leading cause of lung cancer in Canada and the leading cause among non-smokers, linked to more than 3,200 deaths per year (
Chen et al., 2012). As shown in
Figure 1, the lifetime excess cancer risk from radon is orders of magnitude greater than other known carcinogens that can be present in indoor air. Recent Ontario research identifies radon as the second-leading cause of cancer from environmental sources (
CCO and PHO, 2016). Reducing radon in indoor environments is a sound strategy for reducing the overall population risk of lung cancer.
The World Health Organization recommends radon levels in homes should be under 100 Bq/m
3. In Canada, the guideline level is 200 Bq/m
3. Health Canada estimates long-term exposure at the 200 Bq/m
3 level poses a 2% risk of lung cancer for a non-smoker, and a 17% risk for a smoker; risk estimations increase with increased concentration and time exposed (
Health Canada, 2014). While epidemiologic evidence of disproportionate radon risk for children is emergent, it is well established that, for radiation in general, exposures in utero and in childhood pose a greater risk than for adults given the vulnerability of developing systems through rapidly dividing cells (Agency for Toxic Substances and Disease Registry
(ATSDR), 2010;
US EPA, 2005). Moreover, the World Health Organization states that key elements of any national radon program should include radon control measures in any building where people spend a lot of time, including child care settings (
World Health Organization, 2009).
Radon in child care settings
More than half of parents with young children in Canada report using child care, with most of these children (ages 0–4 years) spending at least 30 hours a week in care (
Sinha, 2014). Many child care programs are in residential settings or in public spaces (schools, churches, community centres). A considerable proportion of these are at ground level or in basements where radon levels tend to be higher (
Health Canada, 2012).
Knowledge of radon levels in child care settings is limited, with only a few systematic testing efforts conducted to date. In British Columbia, a radon awareness program was led by the Interior Health Authority. In 2010, a letter promoting testing was sent to every licensed child care facility. In early 2014, free test kits were mailed to 800 licensed child care providers, followed by repeat contact to many. The voluntary program met with challenges associated with child care staff capacity and responsiveness. To date, 850 facilities were mailed a detector, with fewer than half of the detectors (392, or 46%) returned for laboratory analysis. Nevertheless, the testing results are cause for concern. Nearly 11% (43) of the analyzed detectors recorded radon levels above the Canadian guideline, with 9 facilities (2.3%) measuring above 600 Bq/m3, of which 5 (1.3%) were above 1,000 Bq/m3 (G. Baytalan, pers. comm., January 27, 2017). This initiative resulted in lessening radon exposure for many children through successful mitigation or relocation (G. Baytalan, pers. comm., May 29, 2017).
In Quebec, a radon testing initiative was conducted in child care facilities in two regions of the province. Unlike in BC, nearly all of the recruited facilities (which also received free test kits and guidance) successfully completed the testing. The fact the testing program was carried out under the auspices of the provincial Ministry of Health and Social Services in collaboration with the Ministry of Families—the ministry that oversees child care facilities—likely contributed to its success. The other notable feature was the up-front commitment to fund remediation if elevated radon levels were detected (P. Poulin, pers. comm., November 27, 2015). This commitment removed a barrier that many facilities encounter when considering whether to test. Two of the 36 child care centres (5.5%) had at least one test result above the Canadian guideline (
Gagnon et al., 2016). As part of the federal building radon testing program led by Health Canada, approximately 144 buildings in six provinces and territories that contain child care and (or) preschool facilities had been tested. Of these, almost one in ten (9%) had radon levels at or above the Canadian guideline (K. Bush, pers. comm., January 26, 2017).
These results, which reveal elevated radon in some child care facilities, run counter to the public’s and parents’ expectation all such facilities are rendered safe through the licensing process. Given the significant time young children spend in child care environments combined with the cumulative nature of radon exposure, ensuring radon levels are below the guideline in all early learning settings would be well justified.
Recent experiences suggest, however, that we are far from attaining such a goal.