Radon poses a health risk as a hazard when it is present as which condition?

• A. Present outdoors in sunlight
• B. Concentrated indoors in enclosed spaces
• C. Exposed to air during ventilation
• D. No risk in buildings

Answer: (B)

Radon becomes a health hazard when it builds up indoors in enclosed spaces. It’s a radioactive gas that seeps from soil into buildings, and long-term inhalation of its decay products increases lung cancer risk. Outdoors or in well-ventilated areas, radon is highly diluted, so the danger is far lower. When radon concentrates indoors, especially in basements or lower levels with cracks and limited ventilation, exposure can reach levels that pose a real health risk. That’s why the correct condition is concentrated indoors in enclosed spaces. Ventilation and testing help reduce these levels, while outdoor presence or no risk in buildings do not reflect the actual hazard.