Radon concentration is measured as the amount of radon radioactivity in each cubic metre of air (expressed as becquerel per cubic metre; Bq per m3). International guidance suggests that radon levels should be reduced if they are more than 100–300 Bq per m3.

Although radon is present in most buildings, especially in ground-floor rooms and those immediately above or below ground floor, there will be a range of radon levels in homes in any area, and most will be low. Some may be higher, though, this depends partly on the local geology.

Your country may have maps (often available online) that you can use to see whether homes in your area are at more or less risk of having high radon levels. If your home is in an area of increased radon risk, you are advised to have your home tested for radon levels.

Figure 2: Radon risk mapping – the picture shows the patchwork of results from radon measurement campaigns across Europe


Source: Reproduced from Dubois G (2005). An overview of radon surveys in Europe. EUR 21892 EN, EC. Luxembourg: Publications Office of the European Union. © European Communities, 2005.

To determine the radon level in a particular home, it is necessary to measure the concentration of radon in the indoor air. Radon is often measured using small plastic detectors that are placed in the home for several weeks to properly measure the average radon concentration. Most radon measurements require the detectors to be returned to a laboratory for analysis.

Figure 3: Radon detector

radon detector

Source: Reproduced with permission from www.ukradon.org/article.php?key=measureradon.