ALARA (As Low As Reasonably Achievable)

Our basement had high radon levels when moved in and we've had contractors drilling holes and installing radon mitigation fans to reduce the levels. After all that work, we're now at 3.8 pCi/L. Although the level is now less than 4 pCi/L, we're hoping to get it down even lower. In fact, we're aiming to get the radon ALARA (As Low As Reasonably Achievable) or ALARP (As Low As Reasonably Practicable). There's no point exposing members of my house to radon, the second leading cause of lung cancer. I'm eager to see how low we can go.