The following comments are submitted as individual’s comments and do not necessarily reflect the views of Health Canada.
General comment:
It is clearly stated in paragraph (a) of Executive Summary and in paragraph 8 of Introduction, the objective of the present Publication is to describe ICRP system to the protection against radon-222 and radon-220. However, the proposed upper limit of 300Bq/m3, the associated radon dosimetry as well as pooled epidemiological studies are clearly only valid for radon-222. How can the objective be achieved for both radon-222 and radon-220?
Specific comments:
Page 7, line 234-240: construction industries’ responsibility should be included.
Page 7, line 260: It is not always reasonably achievable to reduce indoor levels below a reference level. The sentence “… ALARA below the national reference level” should be modified as follows: "In both cases the process is implemented through the management of buildings which should aim to achieve radon concentrations in ambient indoor air as low as reasonably achievable below the national reference level, recognising that some buildings may still be above the reference level following optimisation. “
Page 8, line 281: I am not sure why incentive and helping provisions should be mentioned in ICRP document. In many countries, there are other health protection/prevention issues having much higher priority than protection against indoor radon.
Page 9, line 320: add “evaluated”; The national action plan should be periodically reviewed and evaluated including …”
Page 9, line 340: add “repeat radon measurement after major reconstruction or renovation”.
Page 22, line 703: why cite UNSCEAR 2000 report when a newer report of 2006 is available.
Page 24, line 753: there is no need to mention the poor solubility of radon in water without further explanation on this issue. What matters is the radon concentration in water which varies considerably.
Page 24, line 765: “The average world value” should be “The world average value”
Page 25, line 805: the equilibrium factor also depends on indoor aerosol properties, this should be added.
Page 25, line 806: the “typical” value of F=0.4 has been challenged recently, see recent publications, such as: Radiat. Environ. Biophys. 50:597-601 (2011), Health Phys. 102:459-462 (2012).
Page 25, para (31): The paragraph starts with “The dose received by the lungs will depend on the PAEC …”. It ends with “the dose correlates better with the radon concentration than with PAEC”. Does it make sense? Should the last sentence be specified for special cases?
Page 26, line 852-858: all numbers cited here are population specific. Please clearly specify the population, UK or Europe?
Page 27, line 905: this paragraph too heavily addressed individual behaviour. Naturally occurring radon becomes a public health concern due to human construction activities. Protective/preventive construction should be added here not only for individuals but also for human society as a whole, as mentioned later in paragraph 46.
Page 38, Fig.5: The illustration for prevention applies to most cases. However, in some high radon areas, the optimisation could start from above the reference level.
Page 39, line 1398: add a word “aimed” between ALARA and “below the national reference levels”. As shown in Fig. 6, to reduce radon below reference level is not always reasonably achievable.
Page 44, Fig.7: For dwellings, the proposed approach requires radon in every home being below 300Bq/m3, even repeatedly through ALARA process. I don’t think this is what ALARA really means. In some cases, homeowners may already tried various mitigation techniques and spent considerable amount of dollars, however, their homes could still have radon above 300Bq/m3 (may be significantly lower than before). For those individuals already tried their best and applied ALARA, asking for repeatedly going through ALARA process associated with financial expenses is, in my view, not reasonable.
Page 45, paragraph 121: The second sentence contradicts with the last sentence.
Page 49, line 1795: The first half of the sentence is wrong. Radon maps can NOT be used for searching for homes with high radon concentration. Only measurement can tell whether a home has high radon or not.
Page 51, line 1899: the word “elevated” should be added in front of “radon”, because everyone is exposed to radon of varying concentration.