From Name
Phil Price

White et al., Steck et al., Klotz et al., and several other groups whose names escape me at the moment, did lots of work on the relationship between short-term concentrations, short-term measurements, long-term concentrations, and long-term measurements. I agree with Steck's assertion that "SHORT-TERM SCREENING TESTS correlate poorly with ANNUAL AVERAGE RADON CONCENTRATION IN LIVING SPACES" --- this is a proven fact, not speculation. Researchers (including Steck himself) have analyzed plenty of data and this is definitely true. Dr. Steck, thank you for weighing in.
I also agree with Cohen's suggestion that where it is possible to adjust for seasonal variation on average, one may as well do so...but of course this will mostly help with bias, it will not substantially improve the correlation between short- and long-term tests.
Here are some things we know about radon measurements:
1. Temporal variability in most houses is very large at the scale of days: the radon concentration often varies by a factor of 2 from one 3-day period to the next.
2. Temporal variability at the scale of weeks is not small: radon concentration can vary by a factor of 1.5 or more from one week the next.
3. Temporal variability at the scale of months is not small: a home's radon concentrations averaged over a season can vary by a factor of 1.5 from one season to another.
4. Within many parts of the country, seasonal variability is fairly predictable because it is associated with climate.
Putting it all together:
Seasonal corrections can, as Cohen suggests, remove the seasonal bias in measurements from a collection of homes (because of item 4 above), but even if you remove the bias there is still a lot of variation between a short-term measurement in a home and the long-term-average concentration in that home (because of items 1 and 2 above). Whether that variation is too large for short-term measurements to be useful for mitigation decisions is not obvious.
All of the stuff above is factual, and is the basic information that I hope everyone involved with radon will remember and internalize.
The following paragraph is my personal opinion, which I expect many people on this listserv disagree with.
Given the poor correlation between short-term measurements and long-term exposure, I used to be bothered by the widespread use of short-term measurements, but for a variety of reasons I am less bothered by it now. If someone buying a $300,000 house ends up spending an extra $1000 for unnecessary mitigation and an extra $50/year to run the system (or whatever the numbers are), it's not that big a deal. If someone incorrectly thinks their long-term average concentration is 3 pCi/L where in fact it's 6 pCi/L, and thus doesn't get a system that they would have been willing to install, that is also not that big a deal. But in both cases, I think it would be much better if the homeowners based their decisions on long-term measurements, and I wish the radon industry would push in that direction.
Phil Price
Lawrence Berkeley National Laboratory.
On Jun 17, 2011, at 1:04 PM, Steck, Daniel wrote:
> --------
> WARNING: At least one of the links in the message below goes to an .exe file,
> which could be malicious. To learn how to protect yourself, please go here:
> http://www.lbl.gov/cyber/services/suspicious-links.html
> --------
> None of my short-term data from the Upper Midwest are based on open-faced charcoal devices. The participants were directed to follow the EPA screening protocol which would preclude open windows. They were also given an 800 number to call if they had questions about deploying detectors or following the protocol. They did both 2 day and 4 day screening tests in each season.
>
>
>
> According to 1992 and 1994 articles by White, the devices used in the EPA surveys were split between open and diffusion barrier charcoal adsorption detectors.
>
>
>
> From: Bernard L. Cohen [mailto:blc@pitt.edu]
> Sent: Friday, June 17, 2011 11:30 AM
> To: Steck, Daniel
> Cc: RADONPROFESSIONALS@LIST.UIOWA.EDU
> Subject: Re: [RNPROF] Short versus long-term measurements for mitigation decisions
>
>
>
> --All of this discussion ignores the difference between a short term charcoal adsorption test with a diffusion barrier and a short term charcoal adsorption test without a diffusion barrier. The former gives a much longer time averaging (3-5 day vs 1-2 day average) at very little extra cost. Another issue is whether windows were kept closed for the short term measurement. Our recommendation was to add 30% to a Summer measurement to estimate the annual average. With attention to these matters, our studies have shown that a charcoal adsorption measurement with a diffusion barrier and with closed windows gives much better results than those described here. Why not make those simple steps standard?
>
> On 6/17/2011 11:05 AM, Steck, Daniel wrote:
>
> 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
>
> ------------------------------------------------------------------------------
> SECURITY/CONFIDENTIALITY WARNING: This message and any attachments are intended solely for the individual or entity to which they are addressed. This communication may contain information that is privileged, confidential, or exempt from disclosure under applicable law (e.g., personal health information, research data, financial information). Because this e-mail has been sent without encryption, individuals other than the intended recipient may be able to view the information, forward it to others or tamper with the information without the knowledge or consent of the sender. If you are not the intended recipient, or the employee or person responsible for delivering the message to the intended recipient, any dissemination, distribution or copying of the communication is strictly prohibited. If you received the communication in error, please notify the sender immediately by replying to this message and deleting the message and any accompanying files from your system. If, due to the security risks, you do not wish to receive further communications via e-mail, please reply to this message and inform the sender that you do not wish to receive further e-mail from the sender.
> ==============================================================================
>
>
>
> ********** RN PROF (Subscription changes - archives) - http://list.uiowa.edu/scripts/wa.exe?SUBED1=RADONPROFESSIONALS&A=1 ***********
>
>
>
>
>
> --
> Bernard L. Cohen
> Physics Dept., University of Pittsburgh
> Pittsburgh, PA 15260
> Tel: (412)624-9245 Fax: (412)624-9163
> e-mail: blc@pitt.edu web site: http://www.phyast.pitt.edu/~blc
> ********** RN PROF (Subscription changes - archives) - http://list.uiowa.edu/scripts/wa.exe?SUBED1=RADONPROFESSIONALS&A=1 ***********
********** RN PROF (Subscription changes - archives) - http://list.uiowa.edu/scripts/wa.exe?SUBED1=RADONPROFESSIONALS&A=1 ***********