I tested my home and found a radon level of just under 4 pCi/l. Is that safe?
Four picocuries per liter of air has been identified by EPA as the recommended action level. There is no absolutely safe level; there is some level of risk associated with all levels of radon. EPA estimates that for an annual average to 4 pCi/l of radon, the risk or lung cancer is 2 per 1,000 persons exposed for non-smokers, and 29 per 1,000 persons exposed for smokers.