How safe is the 4 pCi/L radon “action limit”?
People spend most of their time at home – on average 70%, but more in case of women and particularly, children. Although the 4 pCi/L level has become a benchmark for real estate transactions, it still carries considerable risks – equivalent to getting a chest x-ray or smoking 10 cigarettes each day. (EPA) When relaxing at home, we breathe in radon. It is soluble in blood and circulates through the body and all organs. Some tends to accumulate in fatty issues. Then, almost all is harmlessly exhaled by our lungs or skin until equilibrium is established between the ambient and internal radon concentrations. But radon decay products, radioactive solid particles, much smaller than household dust, float in the air and get trapped in our lungs, trachea, and bronchi. At 4 pCi/L each liter of air contains 70,000 radon atoms. But less than 1% of the inhaled atoms get trapped and we thus accumulate in our airways about 600,000 radioactive particles every hour. When they shoot out alpha particles,
