Scientists at the World Health Organization sort substances into groups. Group 1 is the most serious: these are proven human carcinogens. Radon didn’t just make the list — it was chosen first, because the evidence is strong, consistent, and clear. Children are vulnerable to radon because their lungs are still developing and they breathe faster, taking in more radon per body weight; they spend more time indoors where radon builds up. Children may be breathing radon daily. 更多
