Thread by @jljcolorado

1/ INTERCOMPARISON of AFFORDABLE HOME RADON SENSORS

[TDLR: they compare well]

Radon:
- invisible odorless radioactive gas
- Rises from ground & accumulates indoors
- 2nd leading cause of lung cancer
- EPA link for more background

epa.gov/radon

#TestFixSaveALife

2/ Radon is more of a problem in some places than others, depending on the rocks in the soil. Places with granite are worst. There are maps such as from EPA or Airthings.

November is lung cancer awareness month, EPA promotes hashtag: #TestFixSaveALife

radonmap.com

3/ Radon in homes can be mitigated a limited cost:

- Put a plastic film over the ground
- And a fan that runs all the time (ours uses 75 W, not much). Sucks soil gas and expels outdoors.

#TestFixSaveALife

epa.gov/radon/radon-re…

4/ Unfortunately, radon mitigation is NOT required in most places, e.g. in the US.

It is voluntary. Construction & rental industries resists because of cost

E.g. student rental apts. next to us: high radon, NO mitigation system ==> higher lung cancer rates

#TestFixSaveALife

5/ A radon test is required when you buy a home in some places.

Typically a radon test kit, measures once (e.g. firstalert.com/us/en/products…)

Problem: radon changes all the time. A single point test may be low and radon may still be high at other times (example: our house)

6/ In the last decade some affordable real-time radon measurement devices have been commercialized

I've bought several to monitor our home and to learn about them.

One is from Airthings, cheapest one is $199:

airthings.com/wave-radon

[No conflicts of interest on my part]

7/ Another one is from EcoQube from @EcosenseInc (right now $169):

#TestFixSaveALife

[Again no conflict of interest on my part. I only wish they replied to my emails to technical support!]

ecosense.io/pages/ecoqube

8/ As an experimentalist, knowing quality of such home devices can vary a lot, wondered how well they work

A way to learn: intercompare. Did that in our house. Turned OFF radon fan during travel

Radon up when fan was off, down when on --> mitigation works!

#TestFixSaveALife

9/ So it seems that the RELATIVE response of the @EcosenseInc sensor is good.

What about the ABSOLUTE response? I.e. how much radon is there?

- Harder to do rigorously
- Shortcut: intercompare @EcosenseInc with @airthings sensor

10/ Trick: both report every 1 h. But @airthings applies 24 h rolling average to reduce noise

[This is really annoying, I asked @airthings for an option to remove it, they refused]

So to compare, apply 24 h rolling average to @EcosenseInc data

Done in plot, COMPARE WELL!

11/ I want to stress that this is VERY GOOD for consumer-grade devices.

I have seen a lot worse (e.g. ALL the CO2 sensors that are NOT NDIR = non-dispersive infrared DO NOT WORK!)

12/ For the scientists in the audience, this is the scatter plot

Given short period, and that I am not sure I am exactly duplicating the @airthings processing algorithm for the @EconSenseInc data (dominates high values for tall short spike), this is VERY GOOD

#TestFixSaveALife

13/ These results are consistent with a recent scientific paper (dx.doi.org/10.3390/su1403…), where they tested RadonEye (also from @EcosenseInc) and the @airthings wave.

However, they didn't know about the Airthings 24 h running average, so they reach the wrong conclusions.

14/ Conclusion: portable lower-cost (not really "low-cost" $170-$200) radon sensors work!

Libraries in high radon regions (e.g. @boulderlibrary) should loan these. So people can test for 1 month without having to buy

This is starting to be done for CO2: cbc.ca/news/canada/to…

15/ It is true (as @DavidElfstrom reminds us) that one time radon tests are cheaper (e.g. $15 for this one: amazon.com/-/en/Professio…)

BUT, radon levels change. And 1-hr measurements let you test different rooms, basements, crawl spaces etc. very quickly.

https://twitter.com/DavidElfstrom/status/1595810371687923714

@DavidElfstrom 16/ Radon follows air currents.

But yes, should be more of a problem for basements or ground floors

Not impossible it is a problem in a higher floor if there is an air path (just like for COVID transmission dx.doi.org/10.1093/infdis…), not very likely

https://twitter.com/JustineKirby/status/1595796705219338240

17/ Question from a scientist colleague.

Good idea. Have not tested it against the integrated cheap tests

A colleague (R. Volkamer) has some professional Durridge RAD7 meters that we are now intercomparing. I may bring them home for a wk, do all

https://twitter.com/TimothyHBertram/status/1595816122598973441

18/ I've copied this thread over to Substack, so that it doesn't get lost if Twitter goes kaputt.

Not easy, time consuming, lots of manual tweaking and formatting. @SubstackInc: can you make this more automated?

[If anyone knows how to improve, LMK)

jljcolorado.substack.com/p/lower-cost-r…