Highest Radon Reading?

Top this, guys:
Athol, ID:


  • Radon Test Result = 54.0 pCi/L

  • Test Started 12/21/06 at 11:00 am

  • Test Ended 12/26/06 at 11:00 am

I did one this year and got a 135.0
Called Sun Nuclear, and they said it was the highest reading they’d ever heard of, so they recommended rerunning along wth charcoal canisters as a control.
Ran the test again along with with two canisters and got a 128.4 with my meter and 119.0 with the canisters.
Took the lab awhile to get me my report…when I called they said their program wouldn’t go to 4 digits, and they didn’t know how to write it :slight_smile:

Average Radon Concentration: 135.0 pCi/L
Here are the readings from the monitor:
Data in pCi/l
Time Interval 1 Hr
T 110 T 131 134
129 151 132
123 111 118
126 148 147
130 132 135
140 108 88.0
113 143 142
169 166 177
176 174 165
166 152 159
130 140 123
108 129 132
130 120 121
133 133 110
88.0 107 103
131 121 138
Overall Avg.=135
EPA Protocol Avg.=135

Not the Highest I have ever recorded.

Highest in this Particular Zip Code. (19073)


(Using Sun Nuclear 1027)

23.0 44.0 50.0
44.0 50.5 46.5
50.5 55.5 55.0
49.0 48.0 41.5

44.0 47.5 49.0
30.5 28.5 26.0
22.0 28.5 24.5
26.0 23.0 31.0

31.0 33.0 41.0
26.5 25.0 27.5
31.5 38.5 38.0
40.0 42.5 54.0

64.0 54.0 68.5
77.0 86.5 91.0
80.5 92.5 105
95.5 92.0 79.0

93.5 78.5 72.5
72.0 76.5 87.0
63.5 68.5 60.0
61.5 48.0 38.5

35.0 32.0 23.5
27.5 17.5 20.5
13.5 16.5 17.5

EPA Protocol Avg.=49.8

So what do you do when your house has a reading of 134? I think I would panic and sleep with all the windows open and call a radon mitigation company right away. Is it possible for a true reading to be that high?

Hi Russ
Ill let you know some time next this next week. i set one this last wed. Hopefully i can get through the snow in Castle Rock. With all the snow it should be high. Radon is always higher during a storm.

You betcha.

No need to sleep with the windows open -
Just wire a dosimeter to your alarm clock and go fishing before work, if need be . . .

Yes, recommend mitigation…apparently there’s no reading too high that mitigation cannot take care of.

This was in a high granite area…which are known to have high readings of Radon…like the Blue-ridge mountain area…or is it smokey hills? Can’t remember.

I had a house earlier this year that measured 119pCi/l. I rechecked after running an equipment test, and the test was 111pCi/l. The mitigation contractor put in 2 systems, and the level is now 1.7 pCi/l. This was a 2300 sq.ft. walkout, about 30 years old.

[FONT=Arial]Hi Gents:[/FONT]
[FONT=Arial] [/FONT]
[FONT=Arial]I found the current thread interesting since it underscores a discussion we had already, but, one which some folks rejected. As a refresher, I was pointing out that the radon results from short term monitors (which don’t actually measure radon at all) had HUGE errors associated with them. I gave an example of a data set (which I carefully made up) and used that to explain the point. Some HIs on this board (and I don’t mean the kooky ones) argued that the example set wasn’t a reflection of reality.[/FONT]
[FONT=Arial] [/FONT]
[FONT=Arial]And yet here, in this very thread, is exactly the same data set but using real data. [/FONT]
[FONT=Arial] [/FONT]
[FONT=Verdana][FONT=Arial]If you will recall, my example data set had a mean value of [/FONT][FONT=Arial]47 pCi/l; it had a max of 91 pCi/l and a min of 2 pCi/l and I argued that the actual data set from radon in an house was lognormally distributed just like my pretend data set. Remember also that I told you I had selected the mean value of 47 pCi/l for a VERY important reason. [/FONT][/FONT]
[FONT=Arial] [/FONT]
[FONT=Arial]The gravamen of my argument was that there was only about a 5% chance that the radon concentration you report was actually the annual mean radon concentration in the house. Some of you howled and cried foul, and tried to complain that “It just ain’t so.” [/FONT]
[FONT=Arial] [/FONT]
[FONT=Verdana][FONT=Arial]But let’s look at some real data that has been presented in this thread. If you look at the values that were provided by Mr. Hagarty we see that the mean value Hagarty reported is 50[/FONT][/FONT][FONT=Verdana][FONT=Arial] pCi/l (hmmmm), his data set has a max of 105 and a min of 13 (hmmmm).[/FONT][/FONT]
[FONT=Arial] [/FONT]
[FONT=Arial]The data (as predicted) is lognormally distributed (hmmm) with a whopping GSD of about 1.7! (For those want to know the Shapiro - W statistic test point of Hagarty’s data is 0.9680, and the goodness of fit for the lognormal distribution is 0.9804). [/FONT]
[FONT=Arial] [/FONT]
[FONT=Arial]So you may think you can just take an average and report it – but look, the standard deviation of the data is 24pCi/l and therefore, any value you report is actually plus or minus 47 pCi/L. That is why you use the EPA protocol – so you don’t get sued if an industrial hygienist is hired to find out what the real radon concentration is in an home, and it turns out that your reported value wasn’t even close (not that it will ever happen, since most Industrial Hygienists recognize that the risk associated with radon in homes is sooooo vanishingly small it makes dying from peanut butter exposure look like an impending threat!)[/FONT]
[FONT=Arial] [/FONT]
[FONT=Arial]Based on Mr. Hagarty’s data, I will again reiterate: 1) The EPA protocols for measuring radon in an house were NEVER intended to be used to determine the concentration of radon in any one house; 2) there is a only 5% chance that the result from a short term “radon” measurement is the actual annual mean value of radon in the house; 3) radon monitors don’t measure radon; 4) The results from radon monitors cannot be used to estimate the risk or hazard posed by the actual SLRDs in the home, since, using the EPA protocol one is forced to throw reality, physics, epidemiology, and basic math out the window.[/FONT]
[FONT=Arial] [/FONT]
[FONT=Arial]I’m not saying don’t measure radon. I’m just letting you know that “It just ain’t so” Gents, “It just ain’t so.”[/FONT]

Caoimhín P. Connell
[FONT=Arial]Forensic Industrial Hygienist[/FONT]

(The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, agency, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.)