Consider a house into which radon is emitted through cracks in the base-ment. The total volume of the house is 650 m3 (assume that it is well mixed throughout). The radon source emits 250 pCi s-1 (pCi, or picoCuries, is a unit proportional to the amount of radon gas, and indicates the amount of radioactivity of the gas). Air inflow and outflow can be modeled as a flow of clean air into the house of 722 m3 h-1 , and an equal air flow out. Radon can be considered to be conservative in this problem.
(a) What is the retention time of the house?
(b) What is the steady-state concentration of radon in the house? Express your answer in units of pCi/L.