Across much of the Northern Hemisphere, autumn marks the start of a useful period for measuring radon in homes and workplaces. As buildings are heated and windows tend to stay closed, a long-term measurement can provide a clearer picture of indoor radon levels.
Radon is a naturally occurring gas that can enter buildings from the ground. It cannot be seen or smelled, and concentrations can change with the weather, ventilation and the way a building is used. Measuring over a longer period helps account for those variations and provides a better basis for assessing exposure.
The recommended measurement period varies by country. In Sweden, it begins in October; in Finland, the designated season begins in November. Other countries define the heating season differently. For example, Spain considers the heating season to run from 1 October to 31 May. Countries such as Ireland and the UK do not have a designated measurement season. Instead, they apply seasonal correction factors to measurements carried out throughout the year.
Some countries also recommend longer measurements than others. The practical starting point is therefore to check local guidance before deciding when and for how long to measure.
“Radon levels can differ considerably between neighbouring buildings, so a previous result from the area cannot tell you what the level is in your own home or workplace,” says Karl Nilsson, CEO of Radonova Laboratories. “A long-term measurement gives you a sound basis for deciding whether anything needs to be done. If levels are elevated, the next step is to investigate the cause and decide what mitigation is needed.”
“The current EU Basic Safety Standards Directive has helped introduce radon measurements and measurement periods in workplaces in many European countries. This will also help drive an increase in workplace radon measurements, since the Directive covers both workers and members of the public,” says José-Luis Gutiérrez Villanueva, Specialist Radon Measurement Advisor at Radonova Laboratories.
For larger buildings and workplaces, autumn is also a good time to plan which rooms should be included and how the measurement will be carried out. Whatever the size of the building, using an accredited laboratory helps ensure that the result can be relied on.
