Radon is a gas that comes up through the ground. You can't see it or smell it. But when you're exposed to it, especially for many years, it can be harmful. It's a leading cause of lung cancer.
Where does radon come from? It's made by the decay of radioactive elements in the ground. It often comes from uranium, a silver-grey metal. Uranium is a common element that's found around the world.
How do you get exposed to radon? When the gas rises up from the ground, it enters cracks and gaps in basements and lower floors of buildings. It can be trapped inside homes and buildings that don't have good ventilation. Then, you breathe it in. Radon can also get into water sources that come from underground. So if you drink water from a well, you could be exposed.
When you breathe in radon, radioactive particles become trapped in the lining of your lungs. It gives off very low levels of radiation. Over many years, this radiation can damage your lung cells. It can cause lung cancer.
To protect yourself from radon, have your home tested. If the radon level is high, take steps to fix it. There are systems that can be installed to vent radon gas outside, where it won't be harmful to you.