A nonsmoking woman develops bronchogenic carcinoma. Her house is built over granite bedrock in an area where indoor air measurements reveal accumulation of a radioactive gas seeping from soil through cracks in the foundation. The gas responsible is:
- A Krypton-85
- B Radon ✓
- C Carbon dioxide
- D Formaldehyde
Correct answer: B. Radon
Explanation
Radon-222 is an odourless radioactive noble gas produced by decay of uranium-238 in soil and rock such as granite. It accumulates in poorly ventilated buildings, especially basements, and its alpha-emitting daughters damage bronchial epithelium. Radon is the second most common cause of lung cancer overall and the leading cause among nonsmokers, as established in studies of uranium miners. Formaldehyde is a respiratory irritant linked to nasopharyngeal cancer, krypton is not a soil-derived indoor hazard.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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