Suppose the soil under a single-story house emits 1.0 pCi/m-s (a Curie (C) is a measure of radioactivity, and p is for pico is 10-12). As a worst-case scenario, assume all the gas finds its way through the floor into the house. The hose has 250 m of floor space, and average ceiling height of 2.6 m, and an air change rate of 0.9 ach (ach = number of air changes per hour). The decay rate of radon is 7.6-10 hr. Calculate the steady-state concentration of radon in the house in units of pCi/L.