radon
/ˈreɪdɑn/
noun
- A radioactive gas that has no color or smell, formed from the decay of radium, and can be harmful if found in high levels in buildings.
- Many homes are tested for radon to ensure safe air quality.
- Long-term exposure to radon increases the risk of lung cancer.
- Radon can seep into basements through cracks in the foundation.