EPA recommends that all homes should be monitored for radon. If testing shows levels less than 4 picocuries radon per liter of air (160 Bq/m3), then no action is necessary. For levels of 20 picocuries radon per liter of air (800 Bq/m3) or higher, the home owner should consider some type of procedure to decrease indoor radon levels.[1] For instance, as radon has a half-life of four days, opening the windows once a day can cut the mean radon concentration to one fourth of its level.