Radon does not build up in a residence over time due to its short half-life (3.8 days). Many conditions could affect the measured radon concentration over time in a residence. ... Indoor radon concentrations tend to be higher during seasons when the home is closed up, i.e., winter in colder climates.

How long does it take for radon to build up?

Radon gas can damage cells in your lungs, which can lead to cancer. Radon is responsible for about 21,000 lung cancer deaths each year in the United States, though it usually takes 5 to 25 years to develop.

What time of year is radon highest?

The reason that radon levels in the home can be higher in the summer and winter is two-fold. During the winter, the air in your home tends to be much warmer than the outside air, and this temperature difference creates a vacuum within your home.