Live somewhere? Does it have a ground floor or basement? Then you are at risk for Radon and thus lung cancer. And I recommend you buy the Airthings Wave to find out.

380 people died of Carbon Monoxide poisoning from 2000 to 2009 in Canada, about 38/year. And 3200 died from Radon last year. It kills 100x people as Carbon Monoxide. And CO metres are mandatory, but no one has heard of Radon. Get the news out, forward this blog link!

So I’ve been on a bit of a mission to educate people on Radon of late. If you are already sold on the risk, and just want to measure it, tl;dr: buy the Airthings Wave. But as part of my mission, I’ve run into a set of ‘myths’ that are just not right. And, as I explain to people and they buy the metre and measure, many are finding that they have this problem. So, here’s my PSA.

What is Radon? It is a radioactive gas that is heavier than air and sticks around in your basement.

Myth #1. I tested my house when I moved in.
Fact. Radon is seasonal, it flows with groundwater. So a melt-day in winter is different than the day before.
Fact. You might have a small crack that has formed in your foundation, in your parge-coat, or even in the rock your house is on, it changes over time.

Myth #2. I don’t live in a high-risk area
Fact. Your neighbour might have very low Radon, and you could be very high, its hyper-local. Also, check your local map, but nearly everywhere is at risk

Myth #3. I don’t smoke, or spend much time in my basement
Fact. Radon is the #2 cause of lung cancer in Ontario in non-smokers, and #1 in smokers. 3200 people in Canada die yearly from Radon. 16% of lung cancer deaths (and more of radical life-changing mediation) are caused by it.

Myth #4. I would need some complex industrial system to measure/mitigate, its too complex for me
Fact. Head to Amazon, buy this Airthings Wave. It integrates with your smartphone and gives you easy readings, but, it also works fully standalone. Its run on AA batteries (which are good for a year plus). If you have a problem, its likely just a bit more air circulation is enough anyway.

Myth #5. I don’t know anyone who has this problem, its just a scare tactic
Fact. I now have several readers of this blog who have purchased this item, and found they are over the recommended limit.

Now, you may have seen a map of your Country/County/City, something like the below. Yes, that is true of the average. But, its hyper-local (see myth #2 above). Just because Ontario is less risky than Manitoba, doesn’t mean Waterloo is, or the street I am on. Ontario is 1.6x larger than Texas, that is a big area to average when you are talking about measuring something that varies metre by metre.

So, why do I recommend the Airthings Wave? Well, its really the only one out there that is available that has some easy means of extracting the measurements over time. And over time matters. Its the average exposure that you care about, not the instantaneous. You don’t want the alternatives, the one w/ the LCD screen you check and write down and graph by hand. And the other alternative, the one with the charcoal kit you send away each month? For sure you won’t do that reliably.

But I also recommend it since I bought it, and it works. And it was dead simple.  Insert battery, done. I paired the app from my phone so I can see the pretty graphs, and every once in a while my phone pulls the last N days of values from it, but that’s about it.

Would it be cool if it were WiFi and I had a web page to share? Yes, but it works just great without it.

So, I promise you, if you figured out the technology to open this web page, you can easily buy and use this Radon metre. At best, it will be a bit of money spent that gets you peace of mind and nothing else. At the other end of the spectrum, it could increase you, your children, your pets life expectancy.

If you life in an apartment, well, spend the money on something else 🙂


One of this blog readers recently acquired a Radon detector as I had mentioned earlier. Specifically, the Airthings Wave. And wow, I am glad he did. As you can see from his screenshot, he first put it in one area in his basement (Waterloo, Ontario, Canada), and then relocated it to nearer the sump-hole. And there is a peak of ~1300Bq/m^3 (recall that the ‘safe’ limit is under 200).

Radon is a tricky beast. It moves in ground water (and we had a bit of a thaw yesterday). It comes in through cracks and holes. To check for it, you need to find the worst spot (usually the least ventilated area, and usually near your sump if you have one. Perhaps a cold room as well). And, it takes a bit of time to measure, you can’t just snap it in an hour, it takes days or weeks to get accurate.

Health Canada has a nice FAQ on Radon, and a larger site with more information. 3000 people per year in Canada die from this, but many many more get lung cancer or other affects from it. Don’t be one of them!

It seems BestBuy has removed the product (boo), but you can still get it from Amazon here.

Feel free to add in the comments if you have a Radon measuring system in place, and what your avg/peak is. And please remember, move it around a bit to find the worst area (least circulation/most moisture usually). E.g. don’t place it beside the air-exchanger on your furnace and feel secure 🙂

So an update on the earlier radon gadget. I received the BLE sniffer widget, but, wow, its a bit complex to use. Keeping an eye on the basement Radon, and you can see, it fluctuates quite a bit. We are well under the ‘safety’ limit (which there is some discussion on, some being of the opinion there is no safe limit, others that if its similar to the outdoor levels you can’t do much better).

In Europe, the consensus seems to be 100Bq/m^3 is the threshold to start mediation. Here in Canada the consensus is 200Bq/m^3. My peak is 53Bq/m^3, with an average around 30. So good so far. But its deep-winter here, once spring starts and ground-water flows, maybe I’ll have an issue.

So, worried about your basement? A little more bluetooth gadgetry and you can know for sure. And yes, that test you did once years ago is meaningless, you need to test all the time, see my results.

OK, so i ran the Airthings Wave for a few weeks, I ended up with an average of ~20-30Bq/m^3, which is below the Health Canada worry line of 200Bq/m^3. Now, its time to look at how to make this integrate with my Home Assistant. The device uses Bluetooth Low Energy (BLE), and is integrated via an app on the phone. I have ordered a BLE sniffer, but while I wait for that, I have decided to try the ‘hci snoop debug’ mode on Android. This outputs the HCI frames (in a way that wireshark can read?). On Android Nougat and later it does not output this as a separate file (/sdcard/bt_snoop.log), but instead puts it in the general ‘generate a bug report’ log. The method is in the code here. Inside the larger log file you get a chunk that looks like this:

--- BEGIN:BTSNOOP_LOG_SUMMARY (85476 bytes in) --- 

You would be forgiven for thinking (like me) that this is uuencode. Its not. Going back to the code that generates it, it does:

push preamble to buffer
deflate buffer
base64 buffer
printf footer

OK, so it uses zlib. I should be able to rip the headers off, run it through base64 -d, and then run zlib-flate -uncompress, right? Sadly, that gives some error on the decompression.

And you would think this would be an obvious google search “android unpack bug report logs”. But I must be missing something. It must be this or this (btsnooz, see here). But that gives me the same error. Hmm.

Ah, i see, its this one here, Got it. And here is the file (and you can open this in wireshark) btsnoop. OK, who wants to help decode it? I unpaired, started capturing, paired, let it run for >1 hr to get a radon measurement, and dumped this file. You can see the two devices (Pixel 2 XL <-> TexasIns) talking.

OK, put on your peril-sensitive sunglasses, crack open that wireshark, and open the log file. Race you.


Earlier this week someone brought up Radon gas. He was somewhat surprised that we all knew about it, but we didn’t know enough it turns out. Health Canada has a great resource on it here, including a survey of the prevalence in homes. Radon is the leading cause of lung cancer in non-smokers, and the #2 in smokers, causing ~21000 deaths in the US last year. In a nutshell, natural uranium & thorium decays to lead, and enroute, produces Radon gas.

Now, i was of the impression that since I tested when I bought the house (home inspection), that I was not at risk. Turns out its seasonal (since it follows groundwater). Also, you need to test over a much longer period than I did (~90 days vs the 2 days I did). Ooops. The recommended maximum Radon is 200Bq/m^3, and 6.9% of Canadian homes are there!

Now, I had thought this was more of a regional thing, but it turns out its not. Your neighbour can be fine, and you can be at risk. So, we have carbon monoxide detectors, but why not Radon? The normal test is to take a box of charcoal, but it in your basement for 90days, then ship it to a lab to sniff it. Well, this is a bit of a pain for ongoing metrics.

Enter the Airthings Wave. Designed in Norway, Assembled in Tunisia, fulfilled by Amazon, and delivered by Canada Post. And now the subject of some hacking by me!

OK, so this is bluetooth only. Hmm. So it logs locally, and periodically you open an app on your phone and fetch the stats. For some reason you need an online account with a password. OK, we’ll hack the bluetooth stream later and figure out how to integrate with Home Assistant. But first lets see whats inside. Hmm, deep-recessed pentalobe security screws, obviously don’t want me in here. No problem, just need to find the right bit… we’re in.

OK, below some pictures, I’ll post more once I start in on it. After the pairing and the requisite firmware update for the device, we end up with a fairly nice-looking (if basic) app. It measures temperature/humidity/radon. And it syncs periodically to the device when you ask it to.

OK, lots of pictures of the naked innards. It is using a TI MSP430 as the processor and a LSR SaBLE-X for the BLE (probably this TI reference design of the TI SimpleLink CC2640). Enjoy!