From Name
Steck, Daniel

My thanks to those who continue to think that this is an important  issue worthy of discussion. I have been reluctant to respond to the numerous recent posts since I feel that this discussion list is an inadequate forum for a debate of
the complex issue of the performance of the current EPA screening protocol. However, it is an important issue that deserves a thorough, fact-based discussion before a large audience. I am trying to organize such a discussion.
 
In the meantime I do want to respond to some of the statements using as a basis my research and the current scientific literature on the performance of short-term screening tests in (a) making mitigation derisions and (b) the related issue
of predicting the annual average radon concentration in living spaces. (The latter is usually taken as an adequate standard for judging long-term radon exposure even though year-to-year variations can be substantial.) I don’t claim to have all the answers
but I have spent almost 30 years trying to establish some scientific information about the situation in the Upper Midwest to compare with other research and experience.
 
Rest assured that I want the fragile radon industry to survive and expand but I also want their customers and clients to be well served.  Shot-tem measurements can be useful and I often recommend them for certain applications or to supplement
long-tem measurements (two seasonal). Short-term measurements can provide temporary relief from radon anxiety, catch a few of those extreme cases that Phil J described and also may be fine for post-mitigation tests. (based on ~100 cases).
 
However, SHORT-TERM SCREENING TESTS correlate poorly with ANNUAL AVERAGE RADON CONCENTRATION IN LIVING SPACES , not just in the Upper Midwest, but in national surveys conducted for the EPA (look at the 1994 publications from White et al.), 
ANNUAL AVERAGE RADON CONCENTRATION IN LIVING SPACES  predictions based on  SHORT-TERM SCREENING TESTS are no better than about
a multiplicative factor of 2 to 3. 
 
Is this good enough for a mitigation decision? If the house has a ANNUAL AVERAGE RADON CONCENTRATION IN LIVING SPACES below  1 pCi/l (as many US houses do) then a factor of two uncertainty will not lead to many poor mitigation decisions. 
But, in a radon prone region many people who should mitigate don’t because their SHORT-TERM SCREENING TESTS came back under 4 pCi/L when their ANNUAL AVERAGE RADON CONCENTRATION IN LIVING SPACES was above 4 pCi/L. In my 2005 study, reported at the  AARST conference,
ONLY  SHORT-TERM SCREENING TESTS BELOW about 1 pCi/L reliably predicted (95%)  ANNUAL AVERAGE RADON CONCENTRATION IN LIVING SPACES  below 4 pCi/L.  It took SHORT-TERM SCREENING TEST result of around 6 pCi/L to reliably predict  ANNUAL AVERAGE RADON CONCENTRATION
IN LIVING SPACES  above 4 pCi/L.  If you look at the national data (table 2 White 1994) you see a similar pattern of increasing failure rates of SHORT-TERM SCREENING TESTS as the house measurements approach 4 pCi/L. So  SHORT-TERM SCREENING TESTS may only
fail a few percent of the time when applied to a national sample but fails at a an unacceptable rate in radon regions and for homes whose ANNUAL AVERAGE RADON CONCENTRATION IN LIVING SPACES  is near the action level. Depending on your values, you may be more
tolerant of a false positive failure (mitigating a house whose ANNUAL AVERAGE RADON CONCENTRATION IN LIVING SPACES  is less than 4 pCi/L) than a false negative failure (not mitigating a house with ANNUAL AVERAGE RADON CONCENTRATION IN LIVING SPACES   greater
than 4 pCi/L). We need to find a way to incorporate uncertainty to reduce the decision-making failure rate for homes “near” the action level.
I think that we, as a professional community, can improve mitigation decision making without great economic damage to measurement companies or unnecessary disruption of consumer confidence. However,   progress will require effort, resources,
and respectful cooperation of researchers, industry, and (hopefully) government agencies. I hope you think it is a worthwhile task.
 
 
Sincerely
Dan
 
 
 
Daniel J. Steck, PhD.
Professor, Physics Department, St. John's University
Director: Schaefer Environmental Radiation Laboratory
 
109 PENGL Science Center
Collegeville, MN USA 56321
320-363-3186 or 800-820-3209    FAX 320-363-3202
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