• Are these changes needed?
    My two cents on ground level discharge.
    I did not work on any of the first PA houses, but there were some pretty funky internal walls that were entry points in those houses. I was involved in all of the next set of houses in Clinton NJ. Those houses were in a neighborhood where houses were in multiple 100's. All homes were built by same builder on a few floor plans so information from one house was then used on the others and there were public meetings so homeowners could use the research houses to mitigate there own. We were in the basement of one of these houses where the mitigation was not getting the radon levels down below 4. There was a concern that there was re-entrainment with discharge behind the shrubs outside the house. Someone put dryer vent on the exhaust to run it past the shrubs and away from the house and we watched the radon level drop on the CRM.
    Bruce Henschel did an amazing job developing the encyclopedic Mitigation Manuals, but models are only as good as the data input into them and need to be used with caution. For almost 20 years the VI folks did not look at pressure driven flow into the buildings even though the radon folks knew it existed. Their models did not show it and as late as 5 years ago the standard radiation models used on contaminated sites still did not include it - only included diffusion through the slab.
    I saw re-entrainment from a high level house with shrubbery around it - it is clearly possible. Will it happen in a house below 10 - maybe not that we can measure, but what radon level is safe for ? Is it a function of the inside radon level or the soil gas number?
    If there is a lot of sealing that results in only slightly elevated radon levels in the home, will we have any idea if the soil gas levels are very high. As with much of radon - it all depends.
    It seems to be an area where significant research could lead to an answer, which might be one thing for radon, where we have good options for real-time monitors and a different answers for VI where we don't. And as discussed above, that may only apply to single family homes with larger lots and not urban/suburban areas where homes are closer.
  • 1990 EPA Radon Citizen's Guide
    The Technical Support Document in 1990 was a Draft - The final version was 1992. As I recall, they did some focus group testing on the communications during this intervening time frame as well. There was a significant concern about moving the default testing location from the basement to lowest living level
    In fact NJ chose to not use the revised Citizen's Guide once released. As a State with many areas of significantly elevated radon levels, their data indicated the likelihood of false negatives was higher in NJ than the national data suggested. They believed that tipped the balance to keeping a basement level test in NJ.
    One of the risk visuals was questioned by a Division Director in Region 2 as being not culturally competent on a final review.
    As a draft document the '1990' version was probably never sent to the archive locations.
  • California's New Interactive Radon Map
    We can all certainly wish that our radon programs had been more effective, but we should be looking at the meaningful numbers to assess our progress. Every household in the US does not need to be mitigated, therefore your less than 2% estimate is irrelevant.

    For example:
    There have certainly been more than 2 million homes tested in the US - NJ had 1.185 million homes tested between 1996 and 2019 which is 35% of their homes. Of the homes tested, 180,000 tested over 4 pCi/l and 48.5% of those homes have been mitigated. The State has made regular progress towards its Healthy People 2020 Goal of getting 50% of the homes over 4 mitigated. This has also been an ongoing progress point for their SIRG grants. These numbers are not estimates, but are based on reported information from their certified testers and mitigators.
  • California's New Interactive Radon Map
    While radon maps can be useful tools, they can be a double edged sword. How areas are labeled is critical. Areas labeled 'low' give the impression that there is no need to test.
    Radon is one of the highest environmental carcinogen risks. In a State where citizens have passed a carcinogen warning statute (Prop 65), it seems inappropriate to have a 'low' rating on anything related to radon as there is still substantial risk below 4pCi/l and it is definitely a carcinogen.
    Particularly in areas with high population density, even in a 'low' area, there could be more homes greater than 4 pCi/l than in some states where the whole states are considered 'high'. So the population risk may not be 'low', but people believe there is no need for action .
    The CA map does not seem to have any indication that only outlined areas have been mapped -which is also very misleading for someone not familiar with the background.
  • Air "Purifiers" and Radon
    As Yogi Berra would say 'Dejevu all over again'. What's old is new again

    1) Stating that air cleaners remove radon because the public does not understand the concept of RDP's does not make it accurate. I had this argument with Dade Moeller and his hassock air cleaner probably at the First Radon Symposium. These days it sounds like an open invitation for a class action lawsuit for fraudulent advertising.

    2) When I did presentations back in the day when the Relocation industry bought into only using WL measurements I always got phone calls after this:
    If you remove the radon - you cannot physically have decay products. If you test WL and something changes you still have radon and have no idea what the risk is.

    Having subsequently worked in Indoor Air as well as radon, it is very clear that not all buildings large and small, particularly schools are not always well maintained. Any risk reduction system for a deadly carcinogen needs to be robust and as foolproof as possible.
  • RRNC soil gas matt performance data needed for code approval in Denver
    I would check with the folks on the vapor intrusion side. They tend to have more research dollars and might have some data. Obviously Tom Hatton - but other folks only doing VI as well.
  • Alarms are mandatory now on radon systems
    Fascinating discussion. First to clarify some history. The initial push to move away from band joist exhausts was because we actually saw re-entrainment of exhaust - not leaking from an older style fan within the basement. These were very high homes - in the 100's of pCi/l and the researchers could not get the radon levels down. They attached some dryer hose to the outlet so that the exhaust was past the foundation shrubbery and we could watch the radon levels drop on the CRM.
    As far as I know the re-entrainment issue has not been well researched since then.
    Is it only an issue in very high homes?
    What happens as a home ages and foundation plantings fill in?
    What happens when the driveway is shoveled or plowed for snowing front of exhaust?
    Are lower cost CRM's available now an opportunity to re-visit this idea?
    Would a band-joist exhaust with a CRM actually provide a cost-effective and more aesthetic alternative. Would there be re-entrainment on living levels when windows are open? Has
    Canada ever looked at this?
  • Old Post Mitigation National Survey

    There were formal grant reports on this project. I scanned a bunch of these before I retired. I will see if I can find this them this week now that I have access to my old laptop and flash drives. I will also check with Anita Kopera at NJDEP.
  • Old Post Mitigation National Survey

    NJ did a Follow-up study on Mitigated homes. Then they looked at ones that failed and that was the basis of a training course and update for the manuals. I think Camroden and Bill Brodhead were involved. I may have a copy home that I could access during the week.
  • US Preventative Services Task Force Lung Cancer Screening Recommendations Public Comment
    Unfortunately I do not believe they will include this because the detailed studies that were done to add this screening did not include radon, only smoking. That is why the specific ages and pack years are included as those are the only ones that showed decrease in mortality.
    One option might be to try to add something about radon levels in the research area to get some new data which could justify adding radon to future screenings.
    This Task Force is extremely data driven and without data on specific interventions, they will not recommend.
  • Percentage of radon testing for real estate transactions
    Some of the regulated states may have this information -I know that NJ does through their mandated reporting. I don't know if they can be reached in the current situation.
  • reasons for mounting the fan and exhaust piping outside building envelope in US
    Terry Brennan did do a number of studies on radon in NJ, including at least one that looked at detailed measurements of radon in soil levels around houses. The start of moving away from band joist exhaust was before most of those however.
    During an EPA Office of Research and Development study in Clinton, NJ that Terry worked on they were unable to get the levels below 4pCi/l and finally decided there might be re-entrainment. So they put a hose at the outlet of the band joist and extended the exhaust beyond the foundation plantings and away from the house. We could actually watch on the real time monitor as they levels in the house dropped. These houses were quite high - with many in the 6-800 pCi/l range.
    In public meetings, Terry used to describe the attractive nuisance of a ground level exhaust imagining a kid playing with their parachute man there.
  • I have 2 questions.
    There is a disclaimer for the radon map that is overlooked too often:

    "The Map of Radon Zones was developed in 1993 to identify areas of the U.S. with the potential for elevated indoor radon levels. The map is intended to help governments and other organizations target risk reduction activities and resources. The Map of Radon Zones should not be used to determine if individual homes need to be tested. No matter where you live, test your home for radon—it’s easy and inexpensive. Fix your home if your radon level is 4 picocuries per liter (pCi/L) or higher. Consider fixing if your level is between 2 and 4 pCi/L.

    The Map of Radon Zones was developed using data on indoor radon measurements, geology, aerial radioactivity, soil parameters, and foundation types. EPA recommends that this map be supplemented with any available local data in order to further understand and predict the radon potential for a specific area."

    Most states have updated data and many have updated maps. They should be the first place to get information. One of the problems with maps is their use to downplay the risk and as an excuse for inaction - what is an acceptable level for not venting radon.

  • Solar radon systems
    I attended a Vapor Intrusion training a number of years ago where Bill Brodhead was looking at it for new construction. Sealing was extensive, so only a very low power fan was needed. Of course VI economics are different than for radon mitigation.
  • Pipe Thickness
    In addition to competitive market, the earliest radon work was done by folks whose building experience was in states with no statewide building codes. So it took a while for some of these issues like pipe schedule and garage penetrations to get into practice.
  • and you thought we had problems with radon systems???
    Actually we had to clip a piece out of a video once when the person suggested that # 7 was a way to mitigate for radon.
  • Average post-mitigation levels
    NJ and other states which require the pre and post mitigation results would have this information. However there is potentially a difference between results achieved by certified mitigators and non-certified mitigators. NJ did a study which predates their mandatory program which showed differences between participants in their voluntary program, 'professional' mitigators and homeowners. My recollection is that participants in their program were significantly more effective than other categories.
  • Retirement of Jim Burkhart
    Thanks for all you have done for radon Jim. Hope you enjoy your retirement.

Larainne Koehler

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