What is radon gas and why is it a health concern?

Radon is a naturally occurring radioactive gas that forms when uranium in soil and rocks breaks down. It’s invisible, odourless, and can accumulate in buildings, especially in poorly ventilated areas. Long-term exposure to high levels of radon increases the risk of lung cancer, making it the second leading cause after smoking. Because it builds up gradually, many people are unaware of its presence until testing is done.