Radon is a natural radioactive gas that comes out of the ground. It has no smell, colour or taste, and it is the second biggest cause of lung cancer after smoking. Outdoors it disperses harmlessly, but indoors it can build up, especially in ground-floor rooms, cellars and basements.
The Channel Islands are among the places where that matters most. Much of Jersey and Guernsey sits on granite, one of the rocks that gives off the most radon, and both islands’ homes were surveyed for radon alongside each other in 2012.
How common is high radon in Jersey?
Jersey’s radon guidance estimates that at least 12% of island homes may have radon at a level that needs action, and it recommends that homes with a ground floor are tested. In the 2012 survey, 11 of the 64 Jersey homes tested were above the UK Action Level, and a further 12 were between the Target Level and the Action Level.
Radon varies a great deal from one building to the next, even between neighbours, so the only way to know a building’s level is to measure it.
What the radon levels mean
Radon is measured in becquerels per cubic metre (Bq/m³). The islands use the same levels as the UK:
- 100 Bq/m³ is the Target Level for homes: the level to aim for when reducing radon.
- 200 Bq/m³ is the Action Level for homes: above it, action to reduce radon is recommended.
- 300 Bq/m³ is the reference level for workplaces, as an annual average, under the Ionising Radiations Regulations 2017.
There is no completely safe level. The risk rises with the concentration and with the time spent breathing it.
Testing with a passive detector
The usual first step is a passive detector: a small plastic unit left in a living room and a bedroom for three months, then posted to a laboratory. Jersey’s guidance points to the low-cost measurement packs from UKradon. It is cheap and gives a validated average to compare with the Action Level, and for a single home it is a good place to start.
Its limits are that you get one number, weeks after the test ends, and nothing about what happens in between.
When to monitor continuously
A continuous radon monitor measures around the clock and shows the result as it happens. It is worth it when:
- A test came back high. You can see when radon peaks (often overnight, and in winter when the heating is on and windows are shut) and which rooms are worst, before deciding on a fix.
- You have had remediation done. A radon sump or extra ventilation can be checked within days, instead of waiting another three months.
- You manage many buildings. Landlords, housing providers, schools and employers can watch every monitored room from one dashboard, with an alert when a level is passed.
- It is a workplace. Employers need to assess radon risk, and continuous readings show exposure during working hours, not just a 24-hour average.
A wireless radon monitor made for this
We have had our own wireless LoRaWAN radon monitor developed for exactly these jobs. It runs for five years and more on its battery, with no power or data cable, so it can go in the cellar, ground-floor room or office where the reading needs to be taken, rather than next to the nearest socket. Readings go over LoRaWAN, so it needs no Wi-Fi, and they appear on a dashboard with alerts by email or SMS.
We run LoRaWAN networks across the Channel Islands, so we can supply the monitors on their own or with connectivity, dashboards and alerts. See the radon monitor, read about continuous radon monitoring, or ask us for a quote.