Airthings, the company behind digital sensors that detect radon gas, has built a global map based on frequently updated data pulled from its distributed network of devices installed in customers' homes. Though the precise location of the sensors is hidden to protect users' privacy, the map does break localized regions into areas that Airthings deems lower, medium and high risk to radon gas.

Radon is a colorless and odorless radioactive gas belonging to the group of noble gases. It occurs as an intermediate step as the radioactive elements uranium and thorium decay into lead in the Earth's crust. Even in its most stable form it has a half-life of only 3.8 days. However, as it rises up from the Earth it can build up in enclosed spaces, including buildings.

Studies suggest that high concentrations of radon can cause lung cancer, with the US Environmental Protection Agency (EPA) citing radon as the greatest cause of lung cancer after smoking. It's thought to cause 21,000 cancer deaths per year in the States, 2,900 of which are among non-smokers.

Airthings posits that, because radon levels can fluctuate over time, radon detectors are a useful way to monitor risk. Indeed, the EPA makes radon test kits available from its website.

The company's own detectors start with the Wave – a €199 (US$230) device that you literally wave at for a visual indication of radon concentration in your home – green being good (under 100 Bq per cubic meter), red being bad (over 100 Bq per cubic meter), and amber meaning "temporarily high" (with readings somewhere in between). It can also feed more detailed results to a smart phone. The company makes a Wave Plus sensor, too, which additionally monitors carbon dioxide and volatile organic compounds.

But because these devices are networked, Airthings has been able to pull data to create this global radon map. The map is most heavily populated with data in Europe and North America, where there is clearly a good distribution of Airthings devices. The data from remaining continents is very sparse indeed, though.

It's important to take this for what it is: a tech demo rather than a scientific endeavor. The methods Airthings use to obfuscate the data to protect users' privacy may mean a lone sensor reading is the basis for an entire region. Airthings itself notes that concentrations can vary from home to home, let alone across the large minimum areas the map uses to break down the data.

Perhaps more intesting is how we're starting to see connected, smart devices in the home being used to build a global picture – in this case of radon concentrations, but this could just as easily be for energy consumption, robot vacuum user base, or Alexa voice queries for recipes including yam.

A red block on the map covering your part of the world may not be reason alone for undue alarm, if it helps to raise awareness of the risks posed by radon then that's no bad thing – even if Airthings does clearly stand to gain.

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