Home Air Quality Radon Maps Don’t show Radon Levels in a Specific Building

Radon Maps Don’t show Radon Levels in a Specific Building


NATIONAL REPORT—“Radon maps” is a term that frequently crops up when talking about the risk of radon. A radon map provides a general picture of the areas where there is a risk of high radon levels. These maps are available at both national and regional levels. However, the problem with a radon map is the false sense of security it can give regarding a specific building.

Despite this, Radonova is seeing a growing number of cases where private individuals and workplaces are using radon maps to try to determine the radon level in their specific indoor environment.

“Radon maps are designed to be used when you want a more general geographic breakdown of low-risk and high-risk zones. It is, however, very difficult to draw any reliable conclusions from these about radon levels inside a particular building,” says Bill Rounds, President at Radonova. “The relevant authorities and experts often have good knowledge of the applications for which radon maps can be used. Problems tend to arise when the general public draw conclusions from the maps about radon levels in their own home.”

This is why radon maps do not show radon levels in a specific building.

Below are some of the reasons why radon maps are not a reliable tool for determining radon levels in a specific building.

Radon Maps Do Not Show Local Variations

When producing a radon map, very few measurements are performed in a specific area. Radon levels can vary significantly in such a large area and even between buildings on the same street. Indoor radon levels largely depend on the building’s construction and the air permeability of the soil, which can vary locally.

There is No Standard for Production of Radon Maps

To produce a radon map, measurement data is either obtained by measuring ground radon levels or using data from indoor measurements in the area. With ground radon measurements, there are no clear links between the level of radon in the ground and indoor radon levels. There is certainly an increased risk with high ground radon levels, but other factors, such as construction technology, can have a greater impact.

However, if the radon map is based on indoor measurements, then the results are heavily dependent on the type of building structure where the measurement was recorded. This in turn need not be relevant in any way for another building close by.

Radon Can be Emitted by Building Materials

Radon maps use an accumulative average to represent an area’s general risk and cannot account for individual factors. For example, building materials like blue lightweight concrete used in foundations and aesthetic upgrades that incorporate natural stone emit radon and has the potential to impact results. Because this can cause outliers in “low” radon areas, it’s important to measure each building regardless of its location on a radon map.

The Maps Can be Generated from Old Data

Measured radon levels are to some extent “perishable”. A measurement taken from a few years ago, for example, is no longer reliable. A lot may have happened over the years in and around the building in question to change radon levels. Modernizations, changes to ventilation, and groundwork are just a few examples of factors that can have a major impact on indoor radon levels.

“With this in mind, you shouldn’t rely on radon maps if you want to know what the radon levels are in a specific building. Even if you live in an area that is defined on the radon map as a low-risk zone, there may still be very high radon levels indoors. Given that radon, after smoking, is the most common cause of lung cancer, there is every reason not to rely on this type of map when trying to determine radon levels in the home and at workplaces,” concludes Bill Rounds.

Measure in the Building

The only way to get a reliable picture of radon levels in indoor air is to measure them. This can be done in an affordable manner using radon detectors. Radon maps still have a role to play, however, as they can provide the authorities with an overview that makes it easier to prioritize inspection efforts.

For more information on radon and radon measurement visit www.radonova.com.