The thumbnail may be misleading, see this page for affected products:
Consumers who have these affected products should immediately stop using them and dispose of them in accordance with municipal electronic waste requirements.
Consumers should only purchase electronic radon monitors that have passed performance testing by the Canadian National Radon Proficiency Program (C-NRPP), the Canadian radon certification program recognized by Health Canada. Health Canada provides guidance for measuring radon in homes: Guide for radon measurements in homes - Canada.ca.
To learn about ways to measure the radon gas level in their home with an approved radon detector and how to reduce the radon level if it is high, consumers should visit the following website: Take Action on radon.
how so? never heard of it before.
This is a good start to learn about it
https://cancer.ca/en/cancer-information/reduce-your-risk/know-your-environment/radon
These are approved devices
https://c-nrpp.ca/approved-radon-measurement-devices/
There are cheaper options where you just leave a test item in a specific area for 90 days and then ship it to them to be analyzed, or there’s more expensive electronic options that give quicker readings. It’s possible a local library or other community spot might have electronic ones available to rent/borrow as well.
Generally you want to measure over an extended period of time as the amount of Radon that is present can vary over time. It is also worse in the winter as we keep our doors/windows closed more often giving it a better chance to build up, and measuring in the basement is best as thats where it would build up the most.
If your home happens to be in a spot where there’s too much radon, you’d have to install a system that exchanges the air between the inside/outside at some frequency.
You probably won’t find a house with 0 radon, it’s just a matter of how much is present and if it’s too much.