Consider a house where radon is emitted through cracks in the basement. The total volume of the house is 650 m² (assume that the volume is well mixed throughout). The radon source emits 250 pCi/s (A picoCurie [pCi] 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 m²/h and an equal airflow 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 (units of p Ci/L)?
