Collecting Radon Data In The Name Of Science And Safety


When [Chris Nafis] built an addition onto his historical home he found that a Radon problem, previously mitigated with plenty of concrete, seemed to rear its ugly head yet again. He eventually resigned himself to installing a Radon fan and detector – the latter of which offered no way to store measurement data. He wanted to get a better feel for the short and long-term Radon measurements in his house, in hopes of finding some correlation between temperature, moisture levels, and the total amount of Radon emitted from the ground.

To do this, he disassembled a pair of Radon detectors located in different parts of his house, each of which he wired up to an Arduino. Using his oscilloscope to determine which PCB leads controlled the different LED segments on the displays, he quickly had the Arduinos scraping measurement data from the sensors. [Chris] figured the best way to keep track of his data was to do it online, so he interfaced the microcontrollers with Pachube, where he can easily analyze his historical readings.

An additional goal he set for himself is to trigger the Radon fan only when levels start rising in order to save a little on his electric bill. With his data logging operation in full swing, we think it should be a easy task to accomplish.

32 thoughts on “Collecting Radon Data In The Name Of Science And Safety

  1. Sure, radioactive gas comes into the house… lol.

    No, seriously that’s the first time i hear about something like this.
    Is this a real problem ? Where does that happen ?
    Isn’t it dangerous ?

    1. It happens – radon is naturally present in the soil. Being somewhat heavier than air it accumulates in basements or underground places. Not in choking concentrations ofcourse, but still enough to increase the risk of cancer. See wikipedia for more details on health risks.

    2. Radon is quite dangerous over a long term exposure, and while different parts of the country can have varying levels of radon, you’ll be hard-pressed to avoid it. An installed Radon fan system is a small investment for a substantial benefit. *Any* home can have radon. (Heck, any home can have termites too, but that’s for a different post)

  2. Ok, electricity is dirt cheap. I would not skimp on whatever fan he uses just for a couple extra cents. I always tell everyone that Nuclear Power and whatnot is safe (cause it is), but you do NOT mess with radiation. haha

  3. This is the first time I hear about this, but I don’t live in USA. Having some background would not really hurt this story. Is this something a lot of people have to worry about? Is it specific to some region, or type of terrain?

  4. Radon and Radon Remediation systems are very common here in Wisconsin. Any time the ground is disturbed (to dig a basement) the chance that radon will be detected is quite high. Sometimes it is only in new houses and dissipates after a few years, sometimes it is there forever.

    Remediation systems are simple – a 3″-4″ hole is drilled into the basement floor, a PVC pipe inserted, sealed with caulk and a fan connected to it. Any other holes in the slab, such as a sump must be sealed as well. The exhaust is run up above the roof. The fans are designed to run 24/7 and suck air from the rocks under the slab and exhaust above the roof.

    The fans don’t use a LOT of electricity, but certainly use some. They also have the advantage of drying out the area under the slab and help keep basements a little dryer.

    1. I’d imagine they use a small enough amount of electricity you could get away with using solar power and some batteries to run it, with the occasional topping-off from mains (off-season, bad weather etc)

  5. hey, how easy is it to collect and concentrate it? can we extract electricity from the decay? maybe flow it across some solar panels, or other semiconductors?

    how much electricity could we generate with the ‘radon wells’? enough to run a night light?

    it would be a shame to let all that energy halflife into waste heat…

  6. Radon evacuation fans are not meant to be powered on and off. This excessive cycling will wear out and kill the fan prematurely. The electricity cost will be nothing compared to the $250 for a replacement fan.

    By all means data log the radon measurements, to determine if they only need it on in certain seasons, but don’t have it control the fan itself.

    1. You can pay alot of money to have a radon inspector come by. Or you google for those radon detection kits that you place in your basement for a week or do, then send it off to their lab for analysis.

      They have electronic detectors, but what you need to understand is instantaneous levels are not indicative of a problem, and only an average measurement over a few days to a week is relevant.

  7. nice plots. it would be nice to connect them to local weather data like atmospheric pressure, wind speed, temperature or even furnace use, seasonal ground water levels, etc.

  8. I know there was a few schools that had a huge radon problem where I live where the local government tried to cover it up. I wonder about my university having bad radon levels. Those buildings are 100 years old and they never open the windows.

  9. Cool project. I have the same radon detector unit at my house and am very happy with it.

    Like other people in this comment thread, I would also recommend not turning on and off your radon mitigation fan. As far as I know radon is always coming out of the ground and the detectors have a pretty slow response time, like 2 weeks to get a good reading.
    Basing a feedback loop on one of these detectors, you have no idea how high the radon level really is when your detector reaches a level to turn your fan back on.

  10. The radon levels vary quite a bit as a function of local weather (The earlier suggestion to plot against temperature, humidity, barometric pressure is a good one). when the radon level is naturally low, running a fan vent may not cost a whole lot in terms of electricity, but in northern climates, sucking heat out of the house can be pretty expensive. Think about putting a 4″ hole in your living room and a fast fan sucking air out.. That’s a lot of heat being sucked out.. Turning the fan on and off may not be healthy for the fan (for a variety of reasons), but replacing the fan motor with a DC motor and running it at varying speeds using PWM could maintain a constant radon level, while significancy reducing energy loss.

  11. This is quite interesting. My house is very old, my Grandfather built it 40 years ago. After seeing this post, I grabbed my CD V-700, I gone to the basement and started measuring. I really noticed that the radio-activity is a little higher in the basement than in the attic. Or it’s just placebo effect?

    1. the higher radiation is not necessarily a problem, it’s really just a problem if it is radon.
      brick/concrete houses have a higher radiation count than wooden houses and i guess a concrete basement would also have a higher radiation than the attic even without much radon present.
      as an (external) radiation source radon would also be a harmless alpha radiator. the problem with radon is that you breathe it in, also it decays fairly quickly into radioactive lead and can accumulate.
      quite nasty actually: the uranium in the soil would be harmless, but as radon it can enter the house and your lungs.

    2. Radon gas is heavier than air so it settles in the basement. It also usually comes in the basement thru foundation wall cracks, sump pits, and slab expansion joints.

      When Radium decays into Radon, it expels alpha particles. Radon’s daughter products expel alpha and beta particles

    3. I do not belive CD V-700 can detect Alpha, it’s designed to detect Beta and Gamma. I believe they can be modified to detect alpha, but it’s not trivial. If you see more radiation in the basement, than you do upstairs, or outside, it’s likely because of natural radiation in the stone.

      So you are probably not breathing in the radiation, it’s just getting absorbed by your skin.

      And really, I must take exception to your claim that the your is very old.. 40 years? Gad, we have houses here in upstate NY that were built in the 1600’s. Hmmm and what does that make me, I saw 40 back in.. Say.. I guess I AM OLD.. :)

      A lot of houses up here have dirt floors, and hand laid flagstone walls. Radon just percolates up..

      1. Radon decay series:
        Isotope, half-life, type of decay
        Ra-222, 3.8 days, alpha
        Polonium-218, 3 minutes, alpha
        Lead-214, 27 minutes, beta
        Bismuth-214, 20 minutes, beta
        Polonium-214, 180 microsec, alpha
        Lead-210, 22 years, beta
        Bismuth-210, 5 days, beta
        Polonium-210, 138 days, beta
        Lead-206 (stable)

        It isn’t just the alpha decay of radon that gets you, it is the fact that when it decays, it turns from a noble gas into a (radioactive) heavy metal. This is especially significant when it happens in your lungs.

        Normally an alpha emission isn’t noteworthy because of the very low penetration, but when it happens in your lungs, “very low penetration” is still hitting your cells. And once Radon decays, the heavy metals stay in your lungs, where they continue to decay (in your lungs).

        Some studies show that the risk from Radon is compounded in smokers.

        As previously stated, Radon accumulation is highest in poorly-ventilated areas. It doesn’t take much air exchange to clear it out, though. And really, you can often ventilate the area below your foundation, so you aren’t exchanging your centrally-heated air for outside air.

        1. I had commented earlier about the energy loss from venting the basement.. Your point about venting below the foundation is well taken.

          The decay chain has several alpha emissions, from a detection standpoint, are they all the same?

          I suppose that there is not much generating alpha in my basement besides Radon, so all the detection will be from radon or it’s progeny. The trick is to convert detected decays into radon level.

      2. Uranium-238, after several decays, leads to Radon-222, which continues on with the decay chain I described above.

        When you have one radioactive isotope in your minerals, you have several, because of the many decay products going on.

        Bottom line, if there is Uranium anywhere near you, you probably have radon. Whether or not your Radon is a problem is a much more complicated matter (geology and specific site conditions, construction methods/materials, etc.)

        *most granites contains 10 to 20 ppm Uranium.

  12. Radon lessons learned the hard way:

    We lost a sale of our home when the buyer’s inspector found radon, and then we couldn’t finance purchase of a home in Florida when *our* inspector found radon there and the bank’s underwriter wouldn’t approve the loan, all this costing us much $$$ and time. Here’s what to do:

    For your current home, buy yourself a “Safety Siren” radon detector ($125 from Amazon; there may be other makes/models available by the time you read this.) Find out if you have radon *now*. In the short term, you may be able to reduce environmental radon by just turning ceiling fans and opening windows. Longer-term (and certainly prior to sale, since you must disclose radon) in most localities “sub-slab depressurization” (SSD) is relatively inexpensive (~ $1000). (Florida, where radon is often *in the building materials*, can require a more expensive heat-exchanger ventilation system (~$3,000).

    For your next home, you may not be able to use your meter to inspect the property (it takes 2 days for a reading), but you can hire an inspector to do the test. It’s worth hiring a pro here, because they can tell you how difficult it will be to remediate. If radon is found, think twice about telling your bank/mortgagee. You might get the seller to pay for the remediation, but it will turn up in the closing papers, and the bank’s underwriter may become a bigger obstacle than the radon mitigation itself.

  13. guys,. I’m a certified Radon inspector in California. The “action level” is set at 4 pCi/L. This is a joke..! more people will DIE this year from homes that measure from 2.0 to 4.0 than will from homes above 4.0!. That’s a statistical fact (at least that’s what we were taught in class). It is VERY easy to get a home down to about 2.0 but difficult to get much below that in some cases. This is a much longer topic. The EPA used to give out free radon test kits but stopped that. there is an inexpensive online test kit you can get that’s like 12 dollars or so. its accurate. Ill re-post that link when I see it. Just follow the directions. send in the canisters and go online for your results. easy enough.

    IF YOUR home has concentrations of 2.0 of above, simply install a radon fan and you can find several youtube videos on this. its dead bang easy. There are all sorts of legal requirements for flow indicators and the like, but essentially if you are doing it yourself, you can easily accomplish this. Its a no brainer. I prefer and use Solar powered fans for my radon mitigation but only for my own home. if someone needs help I’m happy to assist. BUT JUST BECAUSE YOU ARE BELOW THE ACTION LEVEL OF 4.0 DON’T IGNORE THIS. It is a totally political issue why the level is 4.0 and not 2.0. its easy to fix.

  14. We recently decided to install a radon mitigation fan in our house and had a monitor much like the one described here running before and after the installation so you can directly see how much difference the mitigation fan has made.
    As several people have already mentioned above, the levels are highly variable so one-off measurements can be misleading in either direction. Before mitigation installation our readings ranged between 1 and 10 pC/L with a long term average around 3pC/L. It is going to take a few months of logging to be sure of the results. Of course this is only our particular case and anyone else’s installation might be more or less effective.

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